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Engine Specific Info and Questions => IDI Engine => Topic started by: lilpig88 on November 16, 2011, 09:06:50 pm
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Hi,
After reading this forum for years and scouring information on this topic for months, I've finally gotten around to my first post.
I'm looking for, like everyone, the best combo of power and efficiency so after a recent re-ring job of my '86 1.6td I threw on a good k14 I had sitting around. I figured the higher gearing of an ACN tranny with a k14 would be a good experiment for better mileage. However, it doesn't really seem to have helped when compared to the lower geared tranny and t3 I had on it before. So here is my question:
Is it normal to run 10 psi down the highway running 65-70 mph (again, 1.6td ACN and k14)? If so, is there a way (besides going with no LDA) to avoid dumping more fuel than i have to with such high boost? As far as efficiency goes, is there advantage to a large turbo running slightly lower boost at cruising speeds? Maybe most importantly, is there a way to get my cruising manifold pressure down? Some folks say they run only 5 psi boost at 70 mph with a similar setup and I can't seem to get that to happen...would love some help. I've had a recent alignment, newer wheel bearings, good tires with full air so the car rolls fine...
Any suggestions to try will be greatly appreciated.
Thanks!
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I think your problem is tuning. The ACN isn't a lower geared trans it is a high geared trans so you shouldn't be turning the rpms. Take your star wheel and maybe make the spring stiffer so the boost fuel comes on later. I usually have 5psi at 70 on flat cruising, but I am intercooled. Also, when I intercooled I gained about 5mpg. I could stay into the fuel and not waste the heat I could use it.
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Thanks! You're right about the ACN...I wrote it wrongly.
I've put the start wheel almost all the way up so I have no LDA advantage (extra fuel) until more throttle. However, I was thinking if I reach 10 psi then it seems the spring pressure won't matter as it'll still reach the full pin limit in the LDA it just won't be as soon. Maybe I'm wrong on that one. I've got a decent commute today so I'll try a few things.
Thanks again!
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The lda is basically a full throttle stop that acts directly on the governor lever. It doesn't actually add fuel on its own. Your right foot still determines the fuel being added. The lda pin can be all the way down but if your foot isn't asking for more fuel you don't get more fuel. On the turbo side of things, there is an adjustment on the turbo for the wastegate. Someone before you might have played with this. I usually back the adjustment off completely on the k14 and it will regulate the boost to about 10 psi max. I found when this adjustment is cranked up for more boost it ends up limiting how far the wastegate valve can actually open which can translate to more exhaust back pressure that can really affect efficiency. Something else that might be happening is the wastegate might be seized and not able to bypass exhaust gases by the turbine.
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I was thinking maybe it was being tuned to give fuel at less pedal input. If you adjust the starwheel down it can allow the boost to push down on the pin at 1psi. If you give it a little more tension and get it to come on around 5psi he could basically operate it like an NA until he really gets on it. I didn't think about a stuck wastegate, but that would do it too.
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What 410 is getting at is it doesn't really make any difference as to fuel usage - it's not like a gasser where the mixture can be "rich" or "lean" but the engine continues at the same speed. With a diesel the engine spins at the maximum speed it can given the load on it for the amount of fuel being injected. More fuel at same load, engine accelerates. Less fuel, it slows down.
We're talking about steady state cruising here - the LDA can impact your fuel usage under acceleration, but only through altering how fast you can accelerate. If you're cruising along the highway at a constant speed and you aren't ever putting the pedal to the floor, the LDA won't have any impact on your fuel usage whatsoever. But if you frequently are mashing the go pedal and blowing smoke while you fly past someone cutting across 3 lanes, then yes you potentially can reduce your fuel usage by adjusting the LDA / max fuel screw. You can also reduce your fuel usage by not doing that.
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I have the same problem on my K14 AAZ rabbit pickup, have an FN trans, hits 10psi on the freeway just barely stepping on the gas. my mileage sucks (38 to 40 mpg) too. should I back out the set screw on the waste gate and see what happens? it's all stock AAZ except for a 2.25 techtonics exhaust.
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I have the same problem on my K14 AAZ rabbit pickup, have an FN trans, hits 10psi on the freeway just barely stepping on the gas. my mileage sucks (38 to 40 mpg) too. should I back out the set screw on the waste gate and see what happens? it's all stock AAZ except for a 2.25 techtonics exhaust.
have you adjusted the wastegate with the set screw? you shouldnt move the wastegate set screw on K series turbos, a tiny bit of turn will make for a big change in my experiences..
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it maxes out at 12 but it gets to 10 pretty quickly. I'm going to start backing it out little by little and see what happens with it.
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I agree about the LDA not affecting the fueling under boost pressure unless he is pressing the pedal hard enough to get into the range where the LDAs motion would be in effect. But, considering he is cruising at 10 psi, it is very likely that he is into the range where the LDA would be in effect and without it appropriately adding fuel according to boost he is hurting engine efficiency.
I wouldn't suspect an issue with the wastegate as that is functioning or he would be spiking higher (stuck closed) or not reaching 10 psi (stuck open).
Like I said, put the LDA back to functioning properly and fix all the other stuff that is affecting steady state cruise like timing, tires, alignment, brakes, etc, etc, etc.
Again, the LDA can't add fuel without causing the car to accelerate. It is burning precisely the amount of fuel needed to sustain the RPM that he is running at, there is no "richness" or wasted fuel going on. Regardless if the LDA is adjusted well, poorly or unplugged, he will be burning the same amount of fuel to keep the engine turning. All you can alter with the LDA is how much fuel is added when accelerating, it has absolutely zero impact on steady state driving regardless of pedal position. The LDA doesn't have any connection to the accelerator whatsoever inside the pump.
The LDA / max fuel screw set the upper limit of how much fuel can be added. Period. Steady state driving is not utilizing the maximum fuel output of your pump, unless you have it turned down so low that you need to keep the pedal to the floor just to maintain highway speeds; if you have it turned down that low, you will be crawling up hills well under the speed limit.
The only thing on the pump that will alter steady state fuel consumption is timing (both static and dynamic). Internal pump pressure would be a very good place to start looking rather than worrying about the LDA, unless the problem is "massive smoke until the turbo spins up" or "not enough fuel to use all the boost"
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My '92 Eco with a Giles-built LDA pump, intercooler, 2.25 in. exhaust, 3.67 R&P and .71 5th gear with the stock K14 runs 8 to 10 psi boost at 70-75 mph steady speed. I routinely get 46-48 mpg and have hit 50 mpg.
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I understand how diesels work and more specifically how the VE pump with LDA works. If the LDA is tuned to a significantly reduced amount of on-boost fuel, then to meet the demand of the load, the pedal will need to be pushed further and the turbo will need to spool higher in order for the LDA pin to move down a bit more to add the additional fuel that's needed to reach equilibrium for that load at that rpm. That added boost comes at the cost of increased back pressure and so a loss of efficiency.
A properly functioning LDA pump will have the LDA impacting the amount of fuel for a significant range of the pedal's movement. Granted it is the upper *portion* of the pedal's movement, but it definitely affects a whole lot wider range than just totally floored. Before the boost pin has moved, the upper portion (1/3-1/4?? depending on tune of the pump) of the pedal will not add any additional fuel. When boost rises, that upper portion of the pedal is "opened up" proportional to the boost. At a load/fuel setting that is generating 10 psi on a 1.6TD, the pump lever should be in the range where the LDA is adding more fuel. If it is adjusted so it isn't, then it is adjusted inefficiently. Period.
Simple test to the OP...
Please disconnect your LDA hose and try another test drive, and report back...
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I understand how diesels work and more specifically how the VE pump with LDA works. If the LDA is tuned to a significantly reduced amount of on-boost fuel, then to meet the demand of the load, the pedal will need to be pushed further and the turbo will need to spool higher in order for the LDA pin to move down a bit more to add the additional fuel that's needed to reach equilibrium for that load at that rpm. That added boost comes at the cost of increased back pressure and so a loss of efficiency.
A properly functioning LDA pump will have the LDA impacting the amount of fuel for a significant range of the pedal's movement. Granted it is the upper *portion* of the pedal's movement, but it definitely affects a whole lot wider range than just totally floored. Before the boost pin has moved, the upper portion (1/3-1/4?? depending on tune of the pump) of the pedal will not add any additional fuel. When boost rises, that upper portion of the pedal is "opened up" proportional to the boost. At a load/fuel setting that is generating 10 psi on a 1.6TD, the pump lever should be in the range where the LDA is adding more fuel. If it is adjusted so it isn't, then it is adjusted inefficiently. Period.
Simple test to the OP...
Please disconnect your LDA hose and try another test drive, and report back...
you mean disconnect it from the pump and PLUG it before driving it so it won't bleed the boost right? :)
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you mean disconnect it from the pump and PLUG it before driving it so it won't bleed the boost right? :)
What he said!!
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Correct... :)
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I do find this continuous multithreaded proclamation that a diesel doesn't run rich with additional fueling a bit of a nonsense. CADman was wrong.
Any engine that is being driven in a vehicle as opposed to an unloaded bench test bed, will run rich, at varing degrees according to the rate of change of drivers input, [just driving naturally and not the mashing of the pedal mentioned], the response rate of the LDA restriction, and the maximum fuel screw.
Few roads in everyday life are flat and empty of the obsticles which need to be negotiated with changes in pedal position. Each movement changes the fuelling which the engine has to play catchup.
Increased black smoke, I agree, doesn't neccessarily mean the engine isn't running near optimally for the situation, but any carbon particles created are definitely unoxidised carbon. Had this carbon been oxidised then that would be further gas production, and so more work obtainable.
When I'm cruising at 70mph on the flat, then my turbo will operate at 2psi or there abouts. Gentle slopes will add or take away pressure accordingly.
I'd like to be convinced that another vehicle running the same speed, but running at 5 to 10psi is running as economically. If they are then either their turbo is more efficient at extracting energy, or less energy is going to coolant and more out of exhaust. I suspect that mostly it is more fuel being burnt, so as the rate of distance coverage is the same, the engine is less efficient, so effectively running richer.
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wow! Sorry about this haphazard response of thoughts.
Thanks for all of the thoughts...I love the conversation.
The test mentioned about the LDA pin position is something I've done and was surprised to find that, while I definitely noticed the difference in power and where it's accessible, the turbo runs around 10 psi for 65-70 mph whether I have my LDA beginning to come "on" early in boost range or late or even disconnected. It obviously takes more pedal to maintain the same speed with no LDA, but boost is nearly the same. The LDA seems to be functioning properly as I can change the amount of smoke (fuel) or lack of smoke and when it comes in the boost range as I change the pin's orientation and the star wheel for spring rate.
The question was mentioned about other things on the car being taken care or in good shape. The tires are new and at a good pressure, a recent alignment was done, brakes are in fine shape (and calipers), timing is at .041" (around 1.05mm) and the wastegate isn't stuck shut (just put the turbo on and made sure the wastegate was alright as I didn't want to take it off so soon)
Thanks again for all of the ideas and thoughts. I love learning more about how these pumps work and affect boost, etc. As I continue to learn and attempt to tune my pump(s) (this is one of a few td's), I'll see if I can add any insight here.
I am interested in the idea of "lack" of fuel leading to the turbo's boost compensating and therefore backpressure and less efficiency. I'll see what I can do about this theory...I feel I've read a lot on here and elsewhere about how boost comes from the thermal energy which comes from fuel which, I guess, is what had me thinking that high boost at cruising speed might be a sign of "excess" fuel (which then would ONLY? show up as excessive smoke?). Given what this thread has discussed so far, I think I have a lot more thinking and to do.
I'd love to hear more about whether or not my 10 psi at 70 mph (around 3,000 rpm) on flat land is acceptable and any more ideas to try to reduce it. In fact, I don't mind if it runs at 10 psi IF that's fine, but I feel there might maybe possibly be a more efficient way to get this motor tuned.
Thanks!
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Uk, I don't think the rich/lean descriptions are relvant to diesels. What do you mean by "rich"? Your post seems out of place, are you actually responding to this thread or did you post here by mistake? Who are you replying to? The fuel to air ratio is constantly changing in a diesel. When it increases, you could say it is "richer", but there isn't some specific stoich mixture that is ideal and the mixture in the combustion chamber is not uniform at all. You could say that it ranges from extremely rich at the injector to completely lean at the perimeter. Particulate unburned or semi-burned fuel is always present to a certain extent due to the relatively uneven distribution of fuel and air in the combustion chamber. Talking about "rich" on a diesel is like talking about an amount of "cold" when describing temperature.
I guess it was partly VAN's mention of more fuel is more rpm, and partly the 10psi at cruise, and partly something in the general topics... Steady state is rarely happening for most drivers, so why talk about it as if it is happening all the time, whilst actually, the engines are in everyday use, playing catchup the economies are varying, and although with the 'better than a gasser' diesel there is almost always an excess of air, leading to almost no unburnt fuel, there is partially burnt fuel, or incorrectly burnt fuel.
Looking at classing load v BSFC, the diesel is much better than the gasser, but even this 'flattened' response curves up at the ends. How often are we at the ends is the big question?
My definition of richness, is simply if a known trip driven twice as identically as possible results in two different fuel economies, then the lower result is effectively from an engine running richer.
Maybe 'richer' is a better term than 'rich', or perhaps 'relatively inefficently'.
Maybe advancing the injection timing would reduce the 10psi @cruise.
This being the GTD site efficiency isn't the main criteria, it's rubber burning power, which may or may not improve cruise mpg.
Coincidentally I recorded a program last night about the development of explosives, from 8thC in China onwards. Fascinating experiments shown including gunpowder, nitro, gun cotton, and a copper 'tin' funnel that was pushed through a 1ft of steel. Climaxing with the fistful of Uranium in 1945.
Examining residues, showed that gunpowder was one of the last of the explosives to leave behind a carbon powder, which was overcome by combining more oxygen chemically to the molecules.
Comparing this to the diesel, the carbon particulate emissions which can be made to vary, are clearly losses to the combustion. I suppose explosives don't have to cater for NOX levels.
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10 psi at 70 mph (around 3,000 rpm)
Bingo - 3K RPM will spool just about any of our turbos to 10+ PSI, even a K24. What transmission is in this vehicle? My highway cruising RPM is more like 2200 in 5th at that road speed...
It obviously takes more pedal to maintain the same speed with no LDA, but boost is nearly the same. The LDA seems to be functioning properly as I can change the amount of smoke (fuel) or lack of smoke and when it comes in the boost range as I change the pin's orientation and the star wheel for spring rate.
Hey Van, if the LDA ONLY affects the fueling when the pedal is completely floored, then why would this guy have to press the pedal further (partial pedal) to maintain the same speed when the LDA is disconnected??
Obviously I'm wrong!! :) So the LDA does come in to play then. However is the total amount of fuel being injected different because the LDA called for it vs the accelerator pedal, or is it the same?
The test mentioned about the LDA pin position is something I've done and was surprised to find that, while I definitely noticed the difference in power and where it's accessible, the turbo runs around 10 psi for 65-70 mph whether I have my LDA beginning to come "on" early in boost range or late or even disconnected.
So regardless if the LDA is connected or not, he gets the same boost at the same road speed... So will adjusting the LDA make any difference to his fuel consumption?
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If he has disconnected it and still gets 10 psi I would say that he needs to start looking at wastegate for sure now. He said his trans earlier and IIRC final 3.67 and 5th is .75.
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So the LDA does come in to play then. However is the total amount of fuel being injected different because the LDA called for it vs the accelerator pedal, or is it the same? So regardless if the LDA is connected or not, he gets the same boost at the same road speed... So will adjusting the LDA make any difference to his fuel consumption?
I would say that in this case because the LDA is maxed out in either case, the amount of fuel is the same and adjusting the LDA won't change his fuel economy for highway cruising. If he gets the rest of the car dialed in so that he isn't always maxed on boost at freeway speeds, then adjusting the LDA will affect his fuel economy by reducing the amount of boost and back pressure necessary for that load.
Agree 100%... :)
If he has disconnected it and still gets 10 psi I would say that he needs to start looking at wastegate for sure now. He said his trans earlier and IIRC final 3.67 and 5th is .75.
If the wastegate is regulating boost consistently to 10 psi, then it is working properly.
Also agree 100%... Wastegate wouldn't be open till 10PSI no matter what, assuming it is set for the 10-12 PSI factory spec.
I'd like to be convinced that another vehicle running the same speed, but running at 5 to 10psi is running as economically. If they are then either their turbo is more efficient at extracting energy, or less energy is going to coolant and more out of exhaust. I suspect that mostly it is more fuel being burnt, so as the rate of distance coverage is the same, the engine is less efficient, so effectively running richer.
Hey Mark, what is your 70 MPH cruising RPM and what turbo do you have? Both of those are factors too... More heat is going to his turbo than yours, but that can be caused by higher engine speed, retarded timing (we've eliminated that one for him already), dragging brakes, bad alignment, bad wheelbearings, hills, headwinds, etc. You could (theoretically) also have a much more restrictive exhaust than he does, though I'm not sure that would make up for that large a difference.
Actually, was there any change in your cruising boost before/after your new rings?
10 psi at 70 mph (around 3,000 rpm)
This one is confusing me... (the 3K RPM bit)... Based on your transmission code, you'd need to have tires that were only about 21" tall to have that engine speed. Are you running 13" wheels with low profile tires?
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Question to OP: what is your IP timing set to? Timing has a huge effect on fuel economy and will affect boost. Retarded timing=relatively higher boost.
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I am no techie but I have an acn tranny in my 85td with a t3.
I cruise just around 3000 rpm at 70mph in 5th gear. If I attack with the car for hills, etc. I see like 12 psi boost on the gage with stock setup with the pedal floored. But when cruising like that I don't see much boost at all. Everytime I go to temporarily pass and hit the pedal there is a slight delay then it builds up, boost goes up and the car starts to pull. Not very good in 5th gear with this setup and driving around if you don't want to speed.
Also with some mixed driving I seem to have lost a few mpg ever since I took the original leaking setup off and start fresh with another sealed pump and pop tested rebuilt injectors.
Also I have a little issue when comparing smoke patterns to the original shape of the used and abused car. It smokes more with a little steady cloud of dark trail as the boost comes on and doesn't clear up as the boost peaks.
I think the fuel delivery is set fine. Any less and it loses power. Just a touch more and the revs start to hang.
Could an lda setting help me get rid of my smoke?
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Question to OP: what is your IP timing set to? Timing has a huge effect on fuel economy and will affect boost. Retarded timing=relatively higher boost.
yea, timing does have alot to do with it. i used to be able to build almost 40psi boost on my VNT with my old 1.5D running super retarded timing..
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I am no techie but I have an acn tranny in my 85td with a t3.
I cruise just around 3000 rpm at 70mph in 5th gear. If I attack with the car for hills, etc. I see like 12 psi boost on the gage with stock setup with the pedal floored. But when cruising like that I don't see much boost at all. Everytime I go to temporarily pass and hit the pedal there is a slight delay then it builds up, boost goes up and the car starts to pull. Not very good in 5th gear with this setup and driving around if you don't want to speed.
Also with some mixed driving I seem to have lost a few mpg ever since I took the original leaking setup off and start fresh with another sealed pump and pop tested rebuilt injectors.
Also I have a little issue when comparing smoke patterns to the original shape of the used and abused car. It smokes more with a little steady cloud of dark trail as the boost comes on and doesn't clear up as the boost peaks.
I think the fuel delivery is set fine. Any less and it loses power. Just a touch more and the revs start to hang.
Could an lda setting help me get rid of my smoke?
IIRC the ACN trans has a 3.67 ring and pinion. that's your problem, you're geared too tall. You need a trans with a 3.94 ring and pinion, you'll run much better with that.
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I am no techie but I have an acn tranny in my 85td with a t3.
I cruise just around 3000 rpm at 70mph in 5th gear. If I attack with the car for hills, etc. I see like 12 psi boost on the gage with stock setup with the pedal floored. But when cruising like that I don't see much boost at all. Everytime I go to temporarily pass and hit the pedal there is a slight delay then it builds up, boost goes up and the car starts to pull. Not very good in 5th gear with this setup and driving around if you don't want to speed.
Also with some mixed driving I seem to have lost a few mpg ever since I took the original leaking setup off and start fresh with another sealed pump and pop tested rebuilt injectors.
Also I have a little issue when comparing smoke patterns to the original shape of the used and abused car. It smokes more with a little steady cloud of dark trail as the boost comes on and doesn't clear up as the boost peaks.
I think the fuel delivery is set fine. Any less and it loses power. Just a touch more and the revs start to hang.
Could an lda setting help me get rid of my smoke?
IIRC the ACN trans has a 3.67 ring and pinion. that's your problem, you're geared too tall. You need a trans with a 3.94 ring and pinion, you'll run much better with that.
i think 3.67 gears are fine for diesels. i love my 3.67s in my diesel.
they put them behind gassers with NO TORQUE, so why wouldnt they work with a TD with some torque?
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I am no techie but I have an acn tranny in my 85td with a t3.
I cruise just around 3000 rpm at 70mph in 5th gear. If I attack with the car for hills, etc. I see like 12 psi boost on the gage with stock setup with the pedal floored. But when cruising like that I don't see much boost at all. Everytime I go to temporarily pass and hit the pedal there is a slight delay then it builds up, boost goes up and the car starts to pull. Not very good in 5th gear with this setup and driving around if you don't want to speed.
Also with some mixed driving I seem to have lost a few mpg ever since I took the original leaking setup off and start fresh with another sealed pump and pop tested rebuilt injectors.
Also I have a little issue when comparing smoke patterns to the original shape of the used and abused car. It smokes more with a little steady cloud of dark trail as the boost comes on and doesn't clear up as the boost peaks.
I think the fuel delivery is set fine. Any less and it loses power. Just a touch more and the revs start to hang.
Could an lda setting help me get rid of my smoke?
IIRC the ACN trans has a 3.67 ring and pinion. that's your problem, you're geared too tall. You need a trans with a 3.94 ring and pinion, you'll run much better with that.
i think 3.67 gears are fine for diesels. i love my 3.67s in my diesel.
they put them behind gassers with NO TORQUE, so why wouldnt they work with a TD with some torque?
oh I forgot you know better than the engineers at VAG sorry my bad...
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well dude, you tell me why they work so well behind a gasser with 50 ft lbs of torque, but they wont work behind a friggen TD?
your logic is flawed ???
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put 4 people in a mk2 jetta td that has an ACN trans and drive from Oakland CA to Modesto on I-580, afterwards tell me if you wish you had an AGS or any other 3.94:1 R&P in it.
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put 4 people in a mk2 jetta td that has an ACN trans and drive from Oakland CA to Modesto on I-580, afterwards tell me if you wish you had an AGS or any other 3.94:1 R&P in it.
uh, theres this thing called a gear shift, and every 4 and 5 speed manual has one. its used to change gear selection when the one you are in simply wont do what you want it to.. if 5th is too tall for hills, grab 4th gear. its an easy decision.
i would rather have to shift more, and have that taller gear for flatter ground cruising.. i may not be able to go up hills in 5th like you, but i can go more miles on a gallon of fuel when were not in the hills.
and uh, i never put 4 people in any of my cars. if you put 4 people in ANY VW, you definitely feel it.
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put 4 people in a mk2 jetta td that has an ACN trans and drive from Oakland CA to Modesto on I-580, afterwards tell me if you wish you had an AGS or any other 3.94:1 R&P in it.
uh, theres this thing called a gear shift, and every 4 and 5 speed manual has one. its used to change gear selection when the one you are in simply wont do what you want it to.. if 5th is too tall for hills, grab 4th gear. its an easy decision.
i would rather have to shift more, and have that taller gear for flatter ground cruising.. i may not be able to go up hills in 5th like you, but i can go more miles on a gallon of fuel when were not in the hills.
and uh, i never put 4 people in any of my cars. if you put 4 people in ANY VW, you definitely feel it.
well I reckon you're all set then bub, shift away.
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oh I forgot you know better than the engineers at VAG sorry my bad...
VAG engineers also designed the alternator belt drive. Look how well that works. ::) I prefer tall gears, and great mileage, and I get both. No compromise, which is why I love my A2.
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I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Wow has this thread been derailed and trashed any mods here?
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oh I forgot you know better than the engineers at VAG sorry my bad...
VAG engineers also designed the alternator belt drive. Look how well that works. ::) I prefer tall gears, and great mileage, and I get both. No compromise, which is why I love my A2.
the engineers at VAG obviously know better than anyone else!
yes, i mean, come on! look at the alternator drive setup. thats a perfect example. it worked. that was it. it worked long enough to get the cars out of the factory.
if i lived in a hilly area, like say, oh, the top of big bear mountain in california, then yes, i would have nothing besides a close geared 3.94 trans in my car. but i dont live in san bernadino county, and i dont drive up alot of long hills. all the hills around here, i can pull in 5th gear with my diesel. i could pull hills in 5th even with an ACN bolted to my diesel, i make boost 1000revs sooner than a T3 setup..
ive said it before, and i will say it again im sure:
ACN IS MY FAVORITE TRANS VW EVER MADE.
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I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
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I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Wow has this thread been derailed and trashed any mods here?
what brought that up? none of us are around ohio..
dont you know, theres no mods running this forum anymore?
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I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
the AVX is the LOWEST geared trans, not highest. the ACN type, and F type trannies were the highest geared. you could either get a 3.67 with a .75 5th gear, or a 3.89 with a .71 5th gear..
anyways, the AVX should have been screaming at 65mph..
but, point of the story being, that an ACN trans, or something similar is a PERFECTLY GOOD MATCH for a 1.6TD.
ilikevwdiesel is the only user on the forum that says the high geared trannies are no good for the torquey diesels. but they are fine for the gutless 1.8L 8v engines they came stock behind..
theres some flawed logic somewhere in this derailed topic..
-
I am no techie but I have an acn tranny in my 85td with a t3.
I cruise just around 3000 rpm at 70mph in 5th gear. If I attack with the car for hills, etc. I see like 12 psi boost on the gage with stock setup with the pedal floored. But when cruising like that I don't see much boost at all. Everytime I go to temporarily pass and hit the pedal there is a slight delay then it builds up, boost goes up and the car starts to pull. Not very good in 5th gear with this setup and driving around if you don't want to speed.
That's basically the difference between a K14 and a T3/K24 right there. The K14, being a smaller turbo, will spool faster (ie with less exhaust manifold pressure) than the larger T3/K24 would. I don't know if that's what VW were shooting for with the larger turbo on the older engines or not, but they certainly downsized aggressively from there - the last traditional turbo they used on the even larger 1.9s was a K04, much smaller again than even the K14. I'd bet those little turbos are at full boost by 1500-1800 RPM, so basically full time at highway speed. The big laggy T3 needs more fuel to spool up, which is exactly what you are describing.
Just curious, what size wheels/tires are you running? Are they 13"?
Also with some mixed driving I seem to have lost a few mpg ever since I took the original leaking setup off and start fresh with another sealed pump and pop tested rebuilt injectors.
Also I have a little issue when comparing smoke patterns to the original shape of the used and abused car. It smokes more with a little steady cloud of dark trail as the boost comes on and doesn't clear up as the boost peaks.
I think the fuel delivery is set fine. Any less and it loses power. Just a touch more and the revs start to hang.
Could an lda setting help me get rid of my smoke?
Your LDA could be set too aggressively for sure. Assuming you believe your max fuel screw is set correctly, there's three adjustments you can make:
- The 'smoke screw' on top - this sets the initial position of the LDA - if you have smoke before boost kicks in, you can back this off a bit.
- The star wheel - this sets the preload on the LDA. Cranking it up (counter clockwise) increases the spring tension, increasing the amount of boost pressure required to start the pin moving. It will also increase the amount of boost needed to reach any particular point on the pin (I think this is likely where you want to start given the symptoms you are describing)
- Rotating the LDA pin - the pin is cut off center, it can be adjusted to be more or less agressive about adding fuel. Depending if it has been tampered with or not, there is a small 'dot' punched in to the metal plate above the rubber diaphragm. There's also a small notch on the edge of the LDA cover. When that dot is in line with the notch in the cover, the LDA is at its most aggressive ramp. Rotating the dot away from the notch will make the LDA less agressive. Note if anyone has fiddled with the pin, the dot may not be in line with the pin anymore.
Also, what's your timing at? If it's off it can cause lots of smoke.
-
I am no techie but I have an acn tranny in my 85td with a t3.
I cruise just around 3000 rpm at 70mph in 5th gear. If I attack with the car for hills, etc. I see like 12 psi boost on the gage with stock setup with the pedal floored. But when cruising like that I don't see much boost at all. Everytime I go to temporarily pass and hit the pedal there is a slight delay then it builds up, boost goes up and the car starts to pull. Not very good in 5th gear with this setup and driving around if you don't want to speed.
That's basically the difference between a K14 and a T3/K24 right there. The K14, being a smaller turbo, will spool faster (ie with less exhaust manifold pressure) than the larger T3/K24 would. I don't know if that's what VW were shooting for with the larger turbo on the older engines or not, but they certainly downsized aggressively from there - the last traditional turbo they used on the even larger 1.9s was a K04, much smaller again than even the K14. I'd bet those little turbos are at full boost by 1500-1800 RPM, so basically full time at highway speed. The big laggy T3 needs more fuel to spool up, which is exactly what you are describing.
Just curious, what size wheels/tires are you running? Are they 13"?
Also with some mixed driving I seem to have lost a few mpg ever since I took the original leaking setup off and start fresh with another sealed pump and pop tested rebuilt injectors.
Also I have a little issue when comparing smoke patterns to the original shape of the used and abused car. It smokes more with a little steady cloud of dark trail as the boost comes on and doesn't clear up as the boost peaks.
I think the fuel delivery is set fine. Any less and it loses power. Just a touch more and the revs start to hang.
Could an lda setting help me get rid of my smoke?
Your LDA could be set too aggressively for sure. Assuming you believe your max fuel screw is set correctly, there's three adjustments you can make:
- The 'smoke screw' on top - this sets the initial position of the LDA - if you have smoke before boost kicks in, you can back this off a bit.
- The star wheel - this sets the preload on the LDA. Cranking it up (counter clockwise) increases the spring tension, increasing the amount of boost pressure required to start the pin moving. It will also increase the amount of boost needed to reach any particular point on the pin (I think this is likely where you want to start given the symptoms you are describing)
- Rotating the LDA pin - the pin is cut off center, it can be adjusted to be more or less agressive about adding fuel. Depending if it has been tampered with or not, there is a small 'dot' punched in to the metal plate above the rubber diaphragm. There's also a small notch on the edge of the LDA cover. When that dot is in line with the notch in the cover, the LDA is at its most aggressive ramp. Rotating the dot away from the notch will make the LDA less agressive. Note if anyone has fiddled with the pin, the dot may not be in line with the pin anymore.
Also, what's your timing at? If it's off it can cause lots of smoke.
thank you for bringing the thread back to its original topic.
-
I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
the AVX is the LOWEST geared trans, not highest. the ACN type, and F type trannies were the highest geared. you could either get a 3.67 with a .75 5th gear, or a 3.89 with a .71 5th gear..
anyways, the AVX should have been screaming at 65mph..
but, point of the story being, that an ACN trans, or something similar is a PERFECTLY GOOD MATCH for a 1.6TD.
ilikevwdiesel is the only user on the forum that says the high geared trannies are no good for the torquey diesels. but they are fine for the gutless 1.8L 8v engines they came stock behind..
theres some flawed logic somewhere in this derailed topic..
Yes, lowest; you know what I meant. 80 mph tops with a tailwind with the AVX and it sounded ready to gernade. 65 mph up the mountain roads limited by power, not gearing. My point is, even with low gears (ala AVX) the car can still be a dog, which mine was.
-
I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
the AVX is the LOWEST geared trans, not highest. the ACN type, and F type trannies were the highest geared. you could either get a 3.67 with a .75 5th gear, or a 3.89 with a .71 5th gear..
anyways, the AVX should have been screaming at 65mph..
but, point of the story being, that an ACN trans, or something similar is a PERFECTLY GOOD MATCH for a 1.6TD.
ilikevwdiesel is the only user on the forum that says the high geared trannies are no good for the torquey diesels. but they are fine for the gutless 1.8L 8v engines they came stock behind..
theres some flawed logic somewhere in this derailed topic..
Yes, lowest; you know what I meant. 80 mph tops with a tailwind with the AVX and it sounded ready to gernade. 65 mph up the mountain roads limited by power, not gearing. My point is, even with low gears (ala AVX) the car can still be a dog, which mine was.
OH!! gotcha.. yea, makes sense now..
my car has 3.67 gearing, and its quicker now than it was with 3.94's..
lol, 80mph with a tailwind.. that reminds me of driving a n/a w/ a GC 4 spd.. the best my n/a's will do with stock government, is 83mph, down hill, on the governor.
-
I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
the AVX is the LOWEST geared trans, not highest. the ACN type, and F type trannies were the highest geared. you could either get a 3.67 with a .75 5th gear, or a 3.89 with a .71 5th gear..
anyways, the AVX should have been screaming at 65mph..
but, point of the story being, that an ACN trans, or something similar is a PERFECTLY GOOD MATCH for a 1.6TD.
ilikevwdiesel is the only user on the forum that says the high geared trannies are no good for the torquey diesels. but they are fine for the gutless 1.8L 8v engines they came stock behind..
theres some flawed logic somewhere in this derailed topic..
Yes, lowest; you know what I meant. 80 mph tops with a tailwind with the AVX and it sounded ready to gernade. 65 mph up the mountain roads limited by power, not gearing. My point is, even with low gears (ala AVX) the car can still be a dog, which mine was.
OH!! gotcha.. yea, makes sense now..
my car has 3.67 gearing, and its quicker now than it was with 3.94's..
lol, 80mph with a tailwind.. that reminds me of driving a n/a w/ a GC 4 spd.. the best my n/a's will do with stock government, is 83mph, down hill, on the governor.
u guys are so FOS it's pathetic...get a room already.
-
u guys are so FOS it's pathetic...get a room already.
Watch this and learn something...
http://www.youtube.com/watch?v=ZHVXbKD5IPk
Carry on.
-
how much money you have into that rig?
-
I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
the AVX is the LOWEST geared trans, not highest. the ACN type, and F type trannies were the highest geared. you could either get a 3.67 with a .75 5th gear, or a 3.89 with a .71 5th gear..
anyways, the AVX should have been screaming at 65mph..
but, point of the story being, that an ACN trans, or something similar is a PERFECTLY GOOD MATCH for a 1.6TD.
ilikevwdiesel is the only user on the forum that says the high geared trannies are no good for the torquey diesels. but they are fine for the gutless 1.8L 8v engines they came stock behind..
theres some flawed logic somewhere in this derailed topic..
Yes, lowest; you know what I meant. 80 mph tops with a tailwind with the AVX and it sounded ready to gernade. 65 mph up the mountain roads limited by power, not gearing. My point is, even with low gears (ala AVX) the car can still be a dog, which mine was.
OH!! gotcha.. yea, makes sense now..
my car has 3.67 gearing, and its quicker now than it was with 3.94's..
lol, 80mph with a tailwind.. that reminds me of driving a n/a w/ a GC 4 spd.. the best my n/a's will do with stock government, is 83mph, down hill, on the governor.
u guys are so FOS it's pathetic...get a room already.
whats your problem dude? who pissed in your cheerios? you are basically saying that 3.67 gears cant be used with a TD.. or any diesel for that matter! the acn trans is the highest trans VW produced, and came behind the lowest HP engine they ever produced. if it works fine on an engine that has no turbo, and a peak torque at about 3 grand, then WHY THE F**K WONT IT WORK WITH A TD?!
i have a VNT on my engine, i can make boost low enough that i could honestly probably run a TDI trans with its rediculous ratios and still be fine. i could probably still accelerate up any hill..
but seriously? WTF IS YOUR PROBLEM?
you pissed off because we said it can be done?
well guess what, an ACN TRANS IS A GREAT MATCH FOR A TD!!!
you basically claim that a 16v trans is the kind you want behind a diesel.. your F***ING high..
i want high gears, not low gears. i would rather have to shift once in a while, rather than be basically wound out going 80 mph..
anyways, do us all a favor, and remove yourself from this thread. you arent helping it one bit. this is turning into a battle of the opinions..
its been gone over a bazillion times.. the diesels get better mileage with taller trannies, but they suffer some acceleration because of the longer gears. thats mostly only true on stock cars.
anyways, this is completely useless to keep arguing.. i can see you wont accept logic..
what are you trying to accomplish here anyways dude? your just getting all pissed off because we said you are wrong..
you are THE ONLY USER ON THE FORUM, who advises AGAINST using 3.67 gearing. anyone with half of a brain knows that 3.67 gears are better for a diesel. when people ask about tranny swaps, the most common answers are "swap in an ACN/AON/ASF/ACL, because they are easy to find, they came in econo-box jettas and golfs." the next most common response is: "swap in a F series (ff, fn, fh, fj) transmision, they were fairly common in rabbits"
and why are you getting soo mad? an AGS is the almost the same thing as an ACN, but with lower gearing. have you actually ever ran a good running TD with an ACN behind it? because i have, and it is AWESOME. ACN is my favorite stock trans, hands down.
if you are trying to make your diesel feel like a GTI, with short gearing, then by all means, use an AGS, or AVX, or AUG, or whatever..
my diesel was funnest to drive with the AUG in it. but it performed much better with the ACN trans in there. mileage was considerably better too..
-
u guys are so FOS it's pathetic...get a room already.
Watch this and learn something...
http://www.youtube.com/watch?v=ZHVXbKD5IPk
Carry on.
Such a nice car :)
-
I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
the AVX is the LOWEST geared trans, not highest. the ACN type, and F type trannies were the highest geared. you could either get a 3.67 with a .75 5th gear, or a 3.89 with a .71 5th gear..
anyways, the AVX should have been screaming at 65mph..
but, point of the story being, that an ACN trans, or something similar is a PERFECTLY GOOD MATCH for a 1.6TD.
ilikevwdiesel is the only user on the forum that says the high geared trannies are no good for the torquey diesels. but they are fine for the gutless 1.8L 8v engines they came stock behind..
theres some flawed logic somewhere in this derailed topic..
Yes, lowest; you know what I meant. 80 mph tops with a tailwind with the AVX and it sounded ready to gernade. 65 mph up the mountain roads limited by power, not gearing. My point is, even with low gears (ala AVX) the car can still be a dog, which mine was.
OH!! gotcha.. yea, makes sense now..
my car has 3.67 gearing, and its quicker now than it was with 3.94's..
lol, 80mph with a tailwind.. that reminds me of driving a n/a w/ a GC 4 spd.. the best my n/a's will do with stock government, is 83mph, down hill, on the governor.
u guys are so FOS it's pathetic...get a room already.
whats your problem dude? who pissed in your cheerios? you are basically saying that 3.67 gears cant be used with a TD.. or any diesel for that matter! the acn trans is the highest trans VW produced, and came behind the lowest HP engine they ever produced. if it works fine on an engine that has no turbo, and a peak torque at about 3 grand, then WHY THE F**K WONT IT WORK WITH A TD?!
i have a VNT on my engine, i can make boost low enough that i could honestly probably run a TDI trans with its rediculous ratios and still be fine. i could probably still accelerate up any hill..
but seriously? WTF IS YOUR PROBLEM?
you pissed off because we said it can be done?
well guess what, an ACN TRANS IS A GREAT MATCH FOR A TD!!!
you basically claim that a 16v trans is the kind you want behind a diesel.. your F***ING high..
i want high gears, not low gears. i would rather have to shift once in a while, rather than be basically wound out going 80 mph..
anyways, do us all a favor, and remove yourself from this thread. you arent helping it one bit. this is turning into a battle of the opinions..
its been gone over a bazillion times.. the diesels get better mileage with taller trannies, but they suffer some acceleration because of the longer gears. thats mostly only true on stock cars.
anyways, this is completely useless to keep arguing.. i can see you wont accept logic..
what are you trying to accomplish here anyways dude? your just getting all pissed off because we said you are wrong..
you are THE ONLY USER ON THE FORUM, who advises AGAINST using 3.67 gearing. anyone with half of a brain knows that 3.67 gears are better for a diesel. when people ask about tranny swaps, the most common answers are "swap in an ACN/AON/ASF/ACL, because they are easy to find, they came in econo-box jettas and golfs." the next most common response is: "swap in a F series (ff, fn, fh, fj) transmision, they were fairly common in rabbits"
and why are you getting soo mad? an AGS is the almost the same thing as an ACN, but with lower gearing. have you actually ever ran a good running TD with an ACN behind it? because i have, and it is AWESOME. ACN is my favorite stock trans, hands down.
if you are trying to make your diesel feel like a GTI, with short gearing, then by all means, use an AGS, or AVX, or AUG, or whatever..
my diesel was funnest to drive with the AUG in it. but it performed much better with the ACN trans in there. mileage was considerably better too..
I'm not mad...u mad bro?
-
I believe it's pretty flat in NE ohio (like the top of your head maybe?), we're talking about the SF Bay area. Ever been there?
Fisherman's Wharf. Bay Bridge. Yep, been there.
FWIW, I drove the car back from North Carolina when I bought it dead stock with the original AVX trans, which you may know has the tallest of all VW transmission R&Ps: 4.25:1. The car barely got out of it's own way. It was dangerously underpowered; 65 mph with the pedal mashed running up the mountain highways. I vowed right then that I would make it run better, which I have, with help from this site. Gearing is just one performance metric. State of tune is another equally important metric. I've since driven my modded Jetta on those same mountan roads. It easily pulls the tall gears on long, steep grades without downshifiting and runs all day with the left laners at arrestable speeds. Low gears are good for the track or an autocrosser, which that 4.25:1 gear set ended up in.
the AVX is the LOWEST geared trans, not highest. the ACN type, and F type trannies were the highest geared. you could either get a 3.67 with a .75 5th gear, or a 3.89 with a .71 5th gear..
anyways, the AVX should have been screaming at 65mph..
but, point of the story being, that an ACN trans, or something similar is a PERFECTLY GOOD MATCH for a 1.6TD.
ilikevwdiesel is the only user on the forum that says the high geared trannies are no good for the torquey diesels. but they are fine for the gutless 1.8L 8v engines they came stock behind..
theres some flawed logic somewhere in this derailed topic..
Yes, lowest; you know what I meant. 80 mph tops with a tailwind with the AVX and it sounded ready to gernade. 65 mph up the mountain roads limited by power, not gearing. My point is, even with low gears (ala AVX) the car can still be a dog, which mine was.
OH!! gotcha.. yea, makes sense now..
my car has 3.67 gearing, and its quicker now than it was with 3.94's..
lol, 80mph with a tailwind.. that reminds me of driving a n/a w/ a GC 4 spd.. the best my n/a's will do with stock government, is 83mph, down hill, on the governor.
u guys are so FOS it's pathetic...get a room already.
well, from that last comment, it could be interpreted that you are aggravated, because of the name calling. im assuming FOS is some sort of abbreviation for a bad name.. and then saying to go get a room? thats not something you usually say to someone unless you are aggravated with them.. ive never heard the response "get a room" used in any way besides a negative manner..
negative comments get negative responses..
-
u guys are so FOS it's pathetic...get a room already.
Watch this and learn something...
http://www.youtube.com/watch?v=ZHVXbKD5IPk
Carry on.
sounds like your timing belt is a little tight...
-
u guys are so FOS it's pathetic...get a room already.
Watch this and learn something...
http://www.youtube.com/watch?v=ZHVXbKD5IPk
Carry on.
sounds like your timing belt is a little tight...
Only if factory spec is a "little tight." 30K on the belt.
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May I suggest an alternative site for those interested in screaming at eachother in a forum: http://vwvortex.com/
See a few pages back where Dieselstink and I were discussing something? See how I decided I had it wrong based on the evidence? See how neither of us insulted one another, called eachother names or implied anything about one another?
Please feel free to use the PM function if you want to have off topic rants at one another, I'm sure the rest of us would appreciate it.
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u guys are so FOS it's pathetic...get a room already.
Watch this and learn something...
http://www.youtube.com/watch?v=ZHVXbKD5IPk
Carry on.
Such a nice car :)
Thanks. It will be one of the few cars I'll dearly miss if something were to happen to it. That said, I was ready to shove it off a cliff until recently when I finally figured out how to fix the alternator belt drive. The bad part was, it would spin the alternator fast enough to keep the light off, but not enough to adequately charge the battery. The only clue it was happening was that the temp and fuel gauges read a little low. The car stranded me more than a few times. It's been flawless since -- knock on soot.
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Also agree 100%... Wastegate wouldn't be open till 10PSI no matter what, assuming it is set for the 10-12 PSI factory spec.
Actually typical wastegate actators are not binary. If the boost is regulated at 12 psi the begin bleeding off exhaust somewhere below that pressure and should be fully open at 12 psi. That is why the Gillis valve is so popular. No pressure is applied to the WGA until the target pressure is reached, unlike stock set ups.
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I was ready to shove it off a cliff until recently when I finally figured out how to fix the alternator belt drive. The bad part was, it would spin the alternator fast enough to keep the light off, but not enough to adequately charge the battery. The only clue it was happening was that the temp and fuel gauges read a little low. The car stranded me more than a few times. It's been flawless since -- knock on soot.
[/quote]
My lawnmower alternator belt's been fine. Only adjusted it once since I installed it. It's been about 6000 miles and not one squeal with all the elec load I can throw at it, even in the rain!
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I was ready to shove it off a cliff until recently when I finally figured out how to fix the alternator belt drive. The bad part was, it would spin the alternator fast enough to keep the light off, but not enough to adequately charge the battery. The only clue it was happening was that the temp and fuel gauges read a little low. The car stranded me more than a few times. It's been flawless since -- knock on soot.
My lawnmower alternator belt's been fine. Only adjusted it once since I installed it. It's been about 6000 miles and not one squeal with all the elec load I can throw at it, even in the rain!
[/quote]
Excellent! 8)
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So the LDA does come in to play then. However is the total amount of fuel being injected different because the LDA called for it vs the accelerator pedal, or is it the same? So regardless if the LDA is connected or not, he gets the same boost at the same road speed... So will adjusting the LDA make any difference to his fuel consumption?
I would say that in this case because the LDA is maxed out in either case, the amount of fuel is the same and adjusting the LDA won't change his fuel economy for highway cruising. If he gets the rest of the car dialed in so that he isn't always maxed on boost at freeway speeds, then adjusting the LDA will affect his fuel economy by reducing the amount of boost and back pressure necessary for that load.
Agree 100%... :)
If he has disconnected it and still gets 10 psi I would say that he needs to start looking at wastegate for sure now. He said his trans earlier and IIRC final 3.67 and 5th is .75.
If the wastegate is regulating boost consistently to 10 psi, then it is working properly.
Also agree 100%... Wastegate wouldn't be open till 10PSI no matter what, assuming it is set for the 10-12 PSI factory spec.
I'd like to be convinced that another vehicle running the same speed, but running at 5 to 10psi is running as economically. If they are then either their turbo is more efficient at extracting energy, or less energy is going to coolant and more out of exhaust. I suspect that mostly it is more fuel being burnt, so as the rate of distance coverage is the same, the engine is less efficient, so effectively running richer.
Hey Mark, what is your 70 MPH cruising RPM and what turbo do you have? Both of those are factors too... More heat is going to his turbo than yours, but that can be caused by higher engine speed, retarded timing (we've eliminated that one for him already), dragging brakes, bad alignment, bad wheelbearings, hills, headwinds, etc. You could (theoretically) also have a much more restrictive exhaust than he does, though I'm not sure that would make up for that large a difference.
Actually, was there any change in your cruising boost before/after your new rings?
10 psi at 70 mph (around 3,000 rpm)
This one is confusing me... (the 3K RPM bit)... Based on your transmission code, you'd need to have tires that were only about 21" tall to have that engine speed. Are you running 13" wheels with low profile tires?
My Quantum is running the standard 3M g/b. Revs at 70mph are a little over 3000rpm. It used to be a little under, but that was when I used the 13" by 185 tyres. I now only run 13" x 175's I think they are x 60 depth. I found they grip the road better and do not track the ruts so much, which is kind of counter intuitive.
Strangely running tyres at 40psi all round, after they warm up, it may drop a few revs to be almost exactly 3000rpm.
When the engine had ringgaps you could walk through, cruise psi was about the same, possibly slightly higher. What the rering did most was to change my cruise mpg by up to 15mpg, but leaving the town mpg only a few points higher.
The smoke on acceleration has almost disappeared, along with the start up smoke. 5 seconds of bosch glowplug is sufficient. [non Duraterm]
Turbo I think is a KKK. Maxes out at a standard 10psi or so.
Tomorrow I hope to hit near 60mpg [UK], as I'm on a rare long trip of about 160miles. Muddying the waters slightly is that I upped the internal pump idle pressure, from 18psi to 40+ so part of my 'stable' mpg values may have been due to poor dynamic advance.
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I am running stock tires on my car.
I am getting around 43mpg right now with the car. Alignment, all new suspension, etc.
With that acn tranny its a pretty fun car to drive around town in gears 1-4, but then again i am no racer.
25% of that commute is up/down twisty mountain pass and the rest is freeway at 70mph.
On those hills I was very surprised to find that I could pull everything in 3rd gear if I really wanted although a few spots would make the car really lug so I shift. But I don't need to go crazy on that part as far as shifting like I thought I would. 5th gear is doable in traffic on flat ground :)
I can really go nuts with this setup around town and rev the hell out of the car and it seems to pull well.
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I am running stock tires on my car.
I am getting around 43mpg right now with the car. Alignment, all new suspension, etc.
With that acn tranny its a pretty fun car to drive around town in gears 1-4, but then again i am no racer.
25% of that commute is up/down twisty mountain pass and the rest is freeway at 70mph.
On those hills I was very surprised to find that I could pull everything in 3rd gear if I really wanted although a few spots would make the car really lug so I shift. But I don't need to go crazy on that part as far as shifting like I thought I would. 5th gear is doable in traffic on flat ground :)
I can really go nuts with this setup around town and rev the hell out of the car and it seems to pull well.
43 MPG US sounds pretty darn good to me!! That's about 5.3L/100KM Canadian. Better than a Prius... :)
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I am running stock tires on my car.
I am getting around 43mpg right now with the car. Alignment, all new suspension, etc.
With that acn tranny its a pretty fun car to drive around town in gears 1-4, but then again i am no racer.
25% of that commute is up/down twisty mountain pass and the rest is freeway at 70mph.
On those hills I was very surprised to find that I could pull everything in 3rd gear if I really wanted although a few spots would make the car really lug so I shift. But I don't need to go crazy on that part as far as shifting like I thought I would. 5th gear is doable in traffic on flat ground :)
I can really go nuts with this setup around town and rev the hell out of the car and it seems to pull well.
if your trans says ACN on the bottom, and you turn 3k going 60mph, then someone had the 5th gear swapped out at some point, or the whole case has been replaces, and its just an ACN case with a mystery gear set in it.
my gasser with stock 185/60/14s and a stock ACN trans will turn 3k @ ~73mph.. and i get 35 mpg.. not bad for a gasser, but certainly not diesel numbers for sure..
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Thanks again!
Looks like after a little sidetrack the conversation is heading in a valuable direction again. It's a mere 5 degrees F at the moment here in MT but I might head out later to check my timing. Not more than 2 month ago when I put this pump on I set it at 1.05mm. A few folks have mentioned to get my pump "dialed in" which I completely agree with and that's why I began this thread (not expected such a long one). So I'm curious if there are any more recommendations for "dialing in" this pump. There seemed to be a supported thought that maybe I'm a little under-fueled? I can adjust the LDA pin orientation to get smoke under full load (and I've pulled back this setting a bit)...this seems to tell me I've got adequate fuel? maybe? Anything I should try even if it's for experimental purposes for you all to learn something? Max fuel screw?
The car seems to drive wonderfully around town and I like the power but while I can drive 80 down the interstate if need be, I feel it should cruise this speed with a little less oomph than it needs at the moment and without such high boost.
I don't want to go looking for a problem, but am simply trying to figure out how to best tune this thing.
Thanks again!
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something interesting to note:
Maybe it's my imagination as the seat of the pants isn't always the best gauge, but on my way home from work for the last 5 miles or so b/4 getting off I-90, I thought the car was cruising along with less effort than before (around 70 mph or so). I looked at my boost gauge and saw a mere 4-5 psi and realized the screw that I had plugging the LDA end of my boost line (I had disconnected the LDA for my trip home for another experiment) had come out. It goes without saying, but just for clarity the manifold pressure was leaking out of the open small LDA hose. Maybe it's nothing, but maybe it's something...figured I'd mention it.
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something interesting to note:
Maybe it's my imagination as the seat of the pants isn't always the best gauge, but on my way home from work for the last 5 miles or so b/4 getting off I-90, I thought the car was cruising along with less effort than before (around 70 mph or so). I looked at my boost gauge and saw a mere 4-5 psi and realized the screw that I had plugging the LDA end of my boost line (I had disconnected the LDA for my trip home for another experiment) had come out. It goes without saying, but just for clarity the manifold pressure was leaking out of the open small LDA hose. Maybe it's nothing, but maybe it's something...figured I'd mention it.
usually, its easier to cruise down the road with 1-2 psi, or even no boost, rather than a considerable amount of boost (4-5psi)
back in the day, when i build my first diesel, i found that i made more power at 15psi, than at 35psi, just because i didnt have the fueling to support 35psi, but i had a turbo capable of producing it..
anyways, you CAN make more power with less boost alot of the times. there is kinda a magic number as far as boost goes. you gotta find the sweet spot tho. my car makes the most power with a good amount of fuel, and about 22psi boost (intercooled)..
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Thanks. I completely agree with you but am really curious as to the best way to achieve this. As I originally posted, I'd love to get my cruising boost down (if that's possible) and am trying to learn how to attain that...Letting manifold pressure leak is not the answer :)
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Where's your boost gauge connected? Is it 'teed' in to your LDA line? ;)
Advance is probably the biggest variable to fuel economy really. If your pump has low internal pressure and isn't getting much dynamic advance, by 3K RPM you'd be running pretty retarded. Retarded timing = increased EGTs / more boost.
Assuming all the driveline stuff (brakes/alignment/wheel bearings) are fine, checking on the pump internal pressure would be the next place I'd focus my attention.
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Thanks. I completely agree with you but am really curious as to the best way to achieve this. As I originally posted, I'd love to get my cruising boost down (if that's possible) and am trying to learn how to attain that...Letting manifold pressure leak is not the answer :)
you could use an air switch, and set your wastegate low, so it opens at like 4-5 psi, hook up one side of the air valve to the wastegate, and not LDA.. then hook the other side of the valve to a boost controller set to a higher psi, say 10-12psi, and hook up the LDA o that side also. then when the switch is off, you have low boost, and no LDA.. when you switch it on, and use the other circuit, the LDA operates, and the boost controller holds the wastegate closed till 10-12psi..
and check your timing, because as was mentioned, retarded timing makes your boost and EGTs go THRU THE ROOF..
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Thanks.
I'd been thinking about doing that (checking internal pressure) but have to do a little searching as to the best/simplest way to do it well. I'll do some searching and see what I can find as far as internal pressure. Or maybe when it warms up a bit I'll swap a different pump (a good one sitting on the shelf) on to see how/if that changes anything.
Thanks again.
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“I'm looking for, like everyone, the best combo of power and efficiency so after a recent re-ring job of my '86 1.6td I threw on a good k14 I had sitting around. I figured the higher gearing of an ACN tranny with a k14 would be a good experiment for better mileage. However, it doesn't really seem to have helped when compared to the lower geared tranny and t3 I had on it before.”
Lil,
First, Mileage,
Some Data for you to consider.
IN 1986 the Nat’l speed limit in the US was still 55 mph, so all of the vehicles built were “geared” around this. HAHAHA geared, I kill me. So your gear ratios and “sweet spot” torque numbers would be set up for 55 in the “people’s republic of the US” at that time. This means when looking for mileage, you are possibly looking at a max around 2800 RPM for best Torque, at least that’s a VW spec.
Oh and this little tidbit from our friends at wiki
85 mph speedometers
On September 1, 1979, in a regulation that also regulated speedometer and odometer accuracy, the National Highway Traffic Safety Administration (NHTSA) required speedometers to have special emphasis on the number 55 and a maximum speed of 85 mph (137 km/h). However, on October 22, 1981, NHTSA proposed eliminating speedometer and odometer rules because they were "unlikely to yield significant safety benefits" and "[a] highlighted '55' on a speedometer scale adds little to the information provided to the driver by a roadside speed limit sign."
So depending on your tire size your MPH may look like this in 5th gear at 3500 rpm
ACH 78
4S, AOP, AGS 84
ACN 84
But the Plot thickens
With your ACN and stock tires 175 70 13 “22.6” in diameter your RPMs are at 2251, well within the torque range, with a little left over for passing.
With the stock tranny, ACH I believe, you would be at 2416, still enough room for passing, but a bit higher RPM.I really don’t think that 200 rpm would have that great of an effect on your mileage.
Now if you were able to get a final drive and 5th combo that brought the RPMs down to around 2500 or less at 70 mph, you would have a whole lot better mileage at 70 than you do now. Obviously, due the pesky laws of physics you will still get better mileage with the engine at 2500 RPMs at 55, than at the same RPMs at 70. But there is no doubt that bringing the RPMs down at 70 MPH will give better mileage than if they are at 3000 – 3500.
My guess would be that if you did this mod, because of the low numerical final drive/differential, you might lack some pep in town and your 5th , because of the lower numerical gear, would, in effect become a limited O/D, only useful for cruising. Now adapting a 6 speed on the other hand, Hmmmm where is that TIG??????[/color][/color]
"So here is my question:
Is it normal to run 10 psi down the highway running 65-70 mph (again, 1.6td ACN and k14)? If so, is there a way (besides going with no LDA) to avoid dumping more fuel than i have to with such high boost? As far as efficiency goes, is there advantage to a large turbo running slightly lower boost at cruising speeds? Maybe most importantly, is there a way to get my cruising manifold pressure down? Some folks say they run only 5 psi boost at 70 mph with a similar setup and I can't seem to get that to happen...would love some help. I've had a recent alignment, newer wheel bearings, good tires with full air so the car rolls fine...
Any suggestions to try will be greatly appreciated.
Thanks!"
If everything is set right, timing, fueling, the “innards” of the pump, the easiest way to control boost is, wait for it, here it comes, with a boost controller, the Ricers use them and there are even manual ones that are modestly priced. I do not recommend using a regular air pressure regulator, they do not last and if the diaphragm blows out your car might get pregnant. No doubt someone from the Great White North will pop in here and say that they are using their Girlfriends hairdryer for a turbo, running on a power inverter and a standard air tool pressure regulator for the past 5 years eh with no problems eh. All I can say to that is “Hose off you hoser”
http://www.youtube.com/watch?v=GLsyM2Crhew
As far as your Turbo, you can see the Map here, but you will have to convert from US to Metric, I did this for my little T2, it was not that hard, and then you can actually plot it. Just something nice to know.
http://www.not2fast.com/turbo/maps/
As to why the high pressure, my guess is some kind of wastegate weirdness, in automotive repair always check the simplest thing first. How did you check the wastegate, if you moved it manually and it did not stick, well that would be the first step. The second step would be to apply air pressure to the wastegate and see how it reacts, even better would be to apply pressure, then use a cutoff valve and make sure the pressure stays in the wastegate can and does not leak out a porous, or cracked diaphragm, “pesky diaphragm again”. It’s possible that you are only getting partial opening due to an internal leak.
Anyway, if I missed something sorry, I’m old. And just Kidding with Our Brothers In The Great White North
Blue Mule
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As Van says your pumps characteristics may not be correct for the 1.05 setting. Retarded is your symptoms. Simply advance the pump and take a trip up the road.
Simple to add a gauge for internal pressure check. Modify spare output bolt, and use a thin extra banjo. Keyword search for other methods.
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and just so you guys know, the LDA will be rockin and rollin by 10psi usually.. like well up its ramp.