k14 highway psi

[Mark(The Miser)UK]

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.

[lilpig88]

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!

[Mark(The Miser)UK]

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.

[vanbcguy]

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? 

[theman53]

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.

[vanbcguy]

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?

[dieselweasel]

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.

[damac]

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?

[R.O.R-2.0]

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..

[ilikevwdiesel]

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.

[R.O.R-2.0]

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?

[ilikevwdiesel]

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...

[R.O.R-2.0]

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 

[ilikevwdiesel]

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.

[R.O.R-2.0]

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.