VWDiesel.net The IDI, TDI, and mTDI source.
General Information => FAQ/Tech Tips/Please Read First => Topic started by: malone on July 07, 2006, 03:20:50 pm
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Introduction
Make your NA diesel (non-turbo) a faster car - an oxymoron? the impossible? Not really, NA (naturally aspirated) diesels can be modified to move a bit quicker than stock.
If you have any questions or suggestions regarding this post, feel free to contribute!
If you're confused by some acronyms like EGT, WOT, NA, etc., then open this page (http://vwdiesel.net/phpBB/viewtopic.php?t=2992) to decipher the acronyms.
Basic Performance Concept
By increasing both airflow and fuel flow through your engine you'll gain some power. Increasing airflow in a turbo diesel is most commonly done by increasing turbo boost, which is easy and inexpensive to do. Increasing airflow in a NA diesel is however limited or costly. Don't fret, there's still room for improvement in NA diesels.
It is possible to gain power by just increasing fuel flow (with nothing done to airflow), however that will potentially increase exhaust smoke and also increase EGT (exhaust gas temperature). Higher EGT indicates higher temperature in the engine internals.
Rule of Thumb
The exhaust smoke should not be more than a light grey haze. Too much smoke may indicate high EGT... not a good idea unless you have an EGT gauge to keep an eye on. Note: ULSD (http://vwdiesel.net/phpBB/viewtopic.php?t=2992) is becoming more common and it reduces visible exhaust smoke so it can be deceiving. The maximum safe EGT for an NA diesel might be 1,400 degrees F. The maximum safe EGT for turbo diesels is around 1,600 degrees F (measured inside exhaust manifold) because they have different engine components that tolerate more heat from turbocharging. Piston cooling oil jets is one feature of turbo diesels. An EGT gauge is not required for virtually all airflow enhancements and some fuelling enhancements.
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The following topics are covered: Maintenance • Airflow • Fuel • Chassis/Other • Big Power
Maintenance
1. Do a compression test. It's nice to see how healthy the engine currently is. Higher compression makes a noticable difference in a NA's peppiness.. turbo diesels not so much (while under boost).
2. If the fuel injector nozzles are old and worn, then replace them or pop-test them if you can. New ones will restore power, economy, and reduce smoke (from improved fuel atomization).
3. Use decent oil, ensure that the headgasket or any engine seals are not leaking, etc. Generally, the engine should be in good condition before you begin modifying. Any VW Tech or mechanic familiar with VW diesels can do a check up. I'm going to stop right here because this thread is about power enhancements, not how to maintain a stock diesel.
Airflow
All airflow upgrades mentioned here are safe and will not increase engine temperature (indicated by EGT).
1. The exhaust manifold upgrade that VW 8v counter-flow gassers have will fit any 8v NA diesel as well.
2. Make sure the air intake filter is clean to ensure no restriction in the airway. If you're curious enough (I haven't personally tried this), you can install a sensitive vacuum gauge between the air filter and the air intake runners to see how much vacuum is produced from the engine trying to suck in air. Less vacuum is better.
3. Many intake piping I've seen stop short, so install intake piping like this for a better cold-air / ram-air effect. It may not suddenly increase power, but it can decrease smoke a little on the highway. A recommended mod because it's inexpensive.
Click image to enlarge
(http://malonetuning.com/howto/1.6na/1_sm.jpg) (http://malonetuning.com/howto/1.6na/1.jpg) (http://malonetuning.com/howto/1.6na/2_sm.jpg) (http://malonetuning.com/howto/1.6na/2.jpg) (http://malonetuning.com/howto/1.6na/3_sm.jpg) (http://malonetuning.com/howto/1.6na/3.jpg) (http://malonetuning.com/howto/1.6na/4_sm.jpg) (http://malonetuning.com/howto/1.6na/4.jpg)
Note: Not all setups shown above are optimal, they just show different designs. When building a cold air intake, consider the following: 1. Place the inlet where the coldest and strongest airflow might be found i.e. in front of vehicle and 2. Minimize intake heat soak generated by nearby hot sources, like the radiator. Heat soak can be reduced using heat shields.
4. Camshaft upgrade from Colt Cams. This seems to work well in turbo diesels, but I haven't personally seen results in NA diesels.
5. Port & polish intake and exhaust ports. It's fairly labour intensive or costly, but if the head needs to be removed for a headgasket replacement or a rebuild, then it may be worth getting a port & polish job done.
Fuel
1. See fuel injectors under Maintenance. Safe for EGT with no change in airflow
2. Advance static fuel pump timing. On 1.6L turbo diesels 1.05mm is the ideal advancing spot, but the NA diesel fuel injectors have a lower breaking pressure (NA 130bar vs. TD 155 bar) and I can't recall the optimal timing at this time. A slightly advanced timing can improve cold starts as well (if the cold-start pull cable is unused). Safe for EGT with no change in airflow
Too much timing advance can increase peak cylinder pressure & reduce efficiency. Don't go too wild on timing advance as it could possibly do some damage.
New 3. If applicable, advance dynamic pump timing - described here (http://vwdiesel.net/phpBB/viewtopic.php?t=7781). Safe for EGT with no change in airflow
4. Look at the throttle lever on the top of the fuel injection pump, swing it all the way to WOT (http://vwdiesel.net/phpBB/viewtopic.php?t=2992) with your hand, notice that it may be stopped by a screw. This is called the "max throttle screw." Back out the screw a bit to let the throttle swing further at WOT. This will result in more fuel & power on demand. More fuel will increase exhaust smoke, but improving the engine airflow will reduce smoke. Will increase EGT
5. For experienced users only: Do the governor mod in the fuel injection pump. Click here (http://vwdiesel.net/phpBB/viewtopic.php?t=2300) for more details. It increases fuel delivery as RPM increases. Decent power improvement. Will increase EGT
6. Send your fuel injection pump (or a spare pump) to Giles (http://vwdiesel.net/phpBB/viewtopic.php?t=7397). His pump really enhances performance; this may be the most significant power mod you'll see in a NA diesel. Here's a testimonial (http://vwdiesel.net/phpBB/viewtopic.php?t=2953). If your pump needs a rebuild, then his service is often recommended. With this pump you can disregard modifications #2-5 above.
Bonus: The pump can be modified to tolerate BioDiesel and today's ULSD (Ultra Low Sulphur Diesel). Safe for EGT regardless of airflow, as the pump is professionally configured and tested in many standard NA diesels
7. If the vehicle still isn't smoking much, then turn in the fuel quantity screw on the side of the injection pump to increase fuel delivery. Use the Bentley manual to find this screw. Will increase EGT
8. Forget about propane unless you can set it up inexpensively, it is not effective on IDIs according to Mr. Sharkey (http://www.mrsharkey.com/lpg.htm). Maybe a 5-8% increase in power at best.
Chassis/Other
1. Get the flywheel lightened. It will improve response during low RPM, especially when accelerating from a stop.
Dave, from Passenger Performance, his personal preference is a flywheel weight of 6 pounds. But anything between 6, 7 and 8 pounds will work. He advised removing the 1" thick ring on the pressure plate side to 0.050" of the flywheel gear teeth, I think, yields 8 pounds. He then removes material on the other side down to the level of the bolt holes to get down to 6 pounds.
2. Suspension and brakes. If the brakes already stop fairly strong and without heat fade (concerning performance), then it may be good enough for spirited driving. A good sport suspension upgrade can make driving the vehicle a pleasure.
3. Ceramic coating. This could be inexpensive if your NA engine is being rebuilt. Do a search in the IDI forum to find threads discussing this topic. Here's one (http://vwdiesel.net/phpBB/viewtopic.php?t=8077) where 935racer outlines what internal parts might be useful to coat and what parts might not.
Big Power
Now.. onto 'big power' enhancements. Strongly recommended is an EGT (Exhaust Gas Temperature) kit (Autometer Pyrometer, for example, which is available at almost any car parts store) tapped into the exhaust manifold:
Nitrous Oxide
Nitrous oxide and turbo-diesel fuel injection pump. Install the two, pipe the nitrous oxide gas into the intake and pipe another one to the LDA device on top of the turbo-diesel fuel injection pump. The LDA senses boost pressure and responds by increasing fuel delivery in the fuel pump. Instead of receiving boost pressure from a turbocharger, it will receive pressure from nitrous oxide gas for the same result.
For best fuel results between NA and nitrous, send your injection pump (even a NA one) to Giles. He will install a LDA on the pump and set the LDA to increase fuel by 100%, while fueling without LDA action will remain stock. In other words, he will turn your regular NA pump into a TD (turbo diesel) pump that responds to changes in forced air pressure.
You may easily see at least double the stock power output on demand. Nitrous Oxide is also cool (as in cold) unlike the compressed air from turbo, so this may be safe for EGT.
Propane
See Propane under the Fuel section in this post.
*** The following modification is still controversial - some feel that NA diesels (except for the 1.9L D, which is already turbo-ready) should not be turbocharged. You make your own decision. ***
Turbocharging
It will be easiest to adapt turbo parts from a 1.6 turbo diesel. Even the turbo + exhaust manifold from a 1.9 turbo diesel will fit. 1.6 turbos are generally bigger (MUCH bigger than any TDI turbo), with no maximum boost until around 3,000 RPM. The 1.9 TD turbos are smaller and although it may be a better choice for daily driving, it will cause higher EGT due to extra backpressure from the smaller turbine. We want to *minimize* EGT for NA engines.
Most importantly, add GOOD intercooling! And avoid smoking much, if at all (or go by your EGT gauge - it's so much easier to install the EGT sensor while you have your turbo exhaust manifold sitting on a bench!). NA diesel longblocks lack piston cooling oil jets and have weaker metal alloys that are less tolerable to heat from turbocharging. So, make sure you have intercooling. If you leave it at stock turbo-diesel power (68hp), it should be good enough for longevity.
A boost gauge is not required unless you're going to change the boost level by bypassing or messing with the turbo's wastegate, or if you just want to see if the turbo's working normally.
eldorado posted a good guideline in maintaining a NA diesel's longevity with turbocharging:
If you've increased the fueling then running more boost will actually help your engine...diesel's run the exact opposite of gassers...the leaner you run a gas engine the higher the egt's. The leaner you run a diesel..ie no smoke the LESS your egt temps will be. when you see smoke..you'll also notice your EGT temps going up.
You will not have any HG issues that is different than a td....they use the same HG, bolts, torques etc..The only issue you'll have is with the pistons...since they're not being cooled by oil. Youy can really help the problem by adding a big oil cooler like the volvo unit. Your oil temps should never be over 210F ever with the volvo oil cooler setup..it's that good, it was made for a 2.4/2.5 gasser that runs hotter turbo temps.
Once you get past running 10-12psi of boost, you definitely need to add an intercooler..this will help your egt temps and give more power to boot.
The most critical part of a turboed N/A diesel is the EGT's...never go past 1400F pre-turbo. I had an original Callaway turbo diesel n/a engine, I put over 120K miles on it (rebuilt engine) and when I gave it away it was still running strong.
You should be able to run 15psi of intercooled boost with no trouble, add fuel until you see a max temp of 1400F and then back it off a hair and you should be good to go. The only thing that will kill the engine is EGT' temps over 1400F and super oil temps. When you're flogging the engine..I would only watch the EGT gauge.
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pure awesomeness, thanks.
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does this effect the MPG? what would you expect to get with those mods?
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does this effect the MPG?
With most modifications the difference in MPG may be neglible when driving normally. If your parts are worn, e.g. injectors, fuel pump, low compression, then restoring them will improve both MPG + power. So keeping the engine healthy w/ maintenance is an important first step.
If you have increased fueling and if you use it often (driving with the pedal to the metal) then you may see lower MPG, but the extra power is nice whenever you need it, i.e. for passing on the highway, going up hills with extra weight.
what would you expect to get with those mods?
More fun!, better passing, less downshifts when going up hills.
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does this effect the MPG?
With most modifications the difference in MPG may be neglible when driving normally. If your parts are worn, e.g. injectors, fuel pump, low compression, then restoring them will improve both MPG + power. So keeping the engine healthy w/ maintenance is an important first step.
If you have increased fueling and if you use it often (driving with the pedal to the metal) then you may see lower MPG, but the extra power is nice whenever you need it, i.e. for passing on the highway, going up hills with extra weight.
what would you expect to get with those mods?
More fun!, better passing, less downshifts when going up hills.
what will the HP and MPG be rated you think?
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I can't answer on HP as I don't recall seeing anyone do a before/after dyno with some modifications.
edit: A 52HP to 77HP gain was claimed with just a fuel pump upgrade, more details here (http://www.vwdiesel.net/forum/index.php?topic=68). I can't personally verify that number but based on experience his pump does work very well in a NA diesel. Here's another testimonial (http://www.vwdiesel.net/forum/index.php?topic=2953).
With an unmodified 1.6 NA engine, you can get either 35 US MPG or 55 US MPG - it all depends on your maintenance, vehicle setup (weight, tires, etc.), and your driving style.
Driving 55 MPH vs. 80 MPH on the highway makes a huge difference in fuel economy. The stock 1.5L to 1.9L NA diesel engine is capable of both speeds. The fuel economy depends on your foot.
I would not worry about MPG difference with most modifications mentioned here. When driving normally the MPG difference should be negligible. However if you're always hammering it with the stock engine and if you'll do the same with a modified engine, then yes you may see a permanent reduction in MPG. The loss in MPG also depends on the extent of your modifications.. there too many variables for me to post an accurate MPG estimate.
If you are anal about MPG, then I bet you won't be pushing the engine hard or speeding all the time (won't be making constant use of the mods).
*edit: Fixed old links.
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I just went through my 1.6d and gave it a bit of a fettle.
I cut some more slots in the MKI grille and attached a air scoop to the rear, then cut the beak off the air box and connected with some decent size tubing - amazing difference!
Good service - much smoohter.
Free-er flowin air filter, bit noisey but worth it!
Did intermediate spring mod, well, I measured the gap between the stops and removed the spring and fitted a pair of copper washers in place of the spring, about 1.8mm it was.
Trouble is I had a real hard time getting the throttle lever back onto the splines, and I marked it up but could I get it back in the right place... er no.. :lol: So the engine was revving away quite fast, so I backed the throttle stop off to compensate, which now leaves me with more throttle travel, surely this is a good thing!? Gave it a bit more fuel and although I thought it felt slower at first, it's just different, I have to now drive in a different style than I was used to but it does seem a fair bit quicker.
I presume that if I strip the capsule down again and add a washer or 2 more and add to the pre tension on the main spring then I will exagerate the effect? as at the minute all I have done is disable the intermediate spring rather than disable it and add extra tension on the main spring.
When tootling along say, light throttle in second, and you accelerate then it goes straight away, as before it would take longer to get going, I presume before when I went to accelerate then all I was doing was adding tension to the intermediate spring.
TBH, reading all the thread on this site about doing this mod are really confusing, and Im a mechainc, it's only now once I have done it and understand it a little more that it makes sense, hats off to you guys that are spanner virgins when you do this mod, I am surprised more don't go wrong! :shock:
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I felt rather "scared to tear in to my pump but i took a spare and tore it down to see what it would be like. The spare was acctually a little different but i got the idea. It helps to just try it but on something your not driving daily.
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Hi Mr brick,
i'm gunna be attempting this mod in the next few weeks, i to have read all the posts and over and then some more just to make sure, i'm sure it will make more sense once i actually crack the lid of the pump. so youre not the only one! :lol:
how do you find about the upper rev range, longer, any more useful power up there, as there should be more fuel now.
hillshy
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Please repost pics.
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I cant seem to find this "governor mod" any where. I am desperatly looking for more power in my 1.6 na
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Please repost pics.
The pictures are now fixed.
The first post has been updated as well, mainly formatting changes for readability.
As for the governor mod, there's a thread in this very forum - here's the link:
http://vwdiesel.net/phpBB/viewtopic.php?t=2300
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I would like to add another easy to perform exhaust upgrade, if you don't mind.
The stock manifold (toilet-bowl) is actually a very good design, as far as factory manifolds go. The reason they get so much rap as a restrictive exhaust is because the exhaust system past the manifold IS restrictive. Take of the down pipe and measure the opening of the stock manifold, it is 2.5" in diameter. The restrictive part of this exhaust system is that it usually is feeding a 1.5" pipe for the exhaust (why did VW make it so small? jeez).
Taking the toilet bowl mating surface and cutting out a 2.5" hole and then using 2.5" all the way back will be just like using one of those dual manifolds, probably better as there is no material in the middle to provide yet another blockage.
Doing this will be the best bang for your buck on exhaust for an N/a for sure. It will be 2.5" pretty much engine back. Run this without resonator and a free flowing muffler, you'll have MAJOR FLOW :)
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Good suggestion, thanks!
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I must add that 2.5" is PLENTY big, actually too big. And a muffler is a must, my setup (in my sig) is waaay too loud and hits the frequencies of a ricer.
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Definitely do an exhaust upgrade to a N/A. Here's a link to my post on what I did on mine. http://www.vwdiesel.net/forum/index.php?topic=20427.msg155903#msg155903 (http://www.vwdiesel.net/forum/index.php?topic=20427.msg155903#msg155903) I used 2.25" I.D. from the toilet bowl back to the axle, then 2" (I just had the needed bends available, as well as a turbo muffler). I would NOT run a N/A without a muffler, because it is loud enough to be annoying in the car and attract the attention of law enforcement officials. If I drive like I did before the mod, I can save a little bit of fuel, but to be honest, the ability to keep up with the majority of traffic as opposed to previously is so nice that I beat on the sucker much more than I did before, so my fuel mileage has dropped. My last 2 tanks, using winter fuel and "spirited driving" (for a N/A) netted me 6.15l/100km or 38.22 mpg U.S. or 45.9 mpg imperial.
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On both Rabbits I did the oversized toilet bowl thing like 8v mentioned.. One had 2.25" pipe and a turbo muffler, the other 2" pipe and a glass pack (Yeah it's sort of loud).. Aside from power gains I've noticed my coolant temps tend to run lower.. Especially when ascending a mountain on a 90F day...
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I must add that 2.5" is PLENTY big, actually too big. And a muffler is a must, my setup (in my sig) is waaay too loud and hits the frequencies of a ricer.
our engines cant hit the frequencies of a ricer, they simply dont spin enough rpms, but if you were comparing decibels, the vw diesel wins every time.
if you like pipes that rap, go straight pipe on your n/a. if you value your hearing, use a flowmaster, magna flow, glass pack, or something that is almost straight through.
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It's probably not the same frequency as a ricer but it has that same annoying "buzz".
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It's probably not the same frequency as a ricer but it has that same annoying "buzz".
thats exhaust resonance or something like that. the sound you get in the cabin at a certain RPM that just freakin buzzes? is your tail pipe coming out under the car, or out behind the car like its supposed to be? cause if it comes out even an inch before the roll pan, you will get alot more noise in your car. i like to have my tail pipes come out to the bumper almost.
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Yeah the tip stuck out a few inches past the body until I put on a 8-10 inch extension trying to quiet it down, it barely helped.
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Yeah the tip stuck out a few inches past the body until I put on a 8-10 inch extension trying to quiet it down, it barely helped.
you got a muffler on it? did you ever think about running a flowmaster (or some sort of good muffler) with a resonator or glasspack in front of it? i loved the way my car sounded with the flowie on it. diesels have a unique sound through a flowmaster, nothing like ive ever heard before..
i had a setup on my n/a rabbit where i had just a glasspack on it, and it was FARKIN LOUD. the exhaust would start rapping at about 1500 rpms, and it would rap louder the more gas you gave it. then i had some sort of generic welded muffler on it with some bigger pipe, sounded alot better, but it was still kinda loud. thats what makes me say that the combo of both a muff and a resonator would be good if you want quiet and flow.
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Right now it's just 2.5 straight ;D
I've been looking for a muffler but I'm having a hard time finding a good one that'll fit.....is Thrush brand any good? The napa here has an oval one with offset inlet/outlets but I need either both center or at least the inlet centered.
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Right now it's just 2.5 straight ;D
I've been looking for a muffler but I'm having a hard time finding a good one that'll fit.....is Thrush brand any good? The napa here has an oval one with offset inlet/outlets but I need either both center or at least the inlet centered.
i would at least get a cheap all welded muffler. and thrush turbo mufflers are kinda like a raptor muffler, bottom of the barrel muffler that will do the job, but who knows how well it flows. a glass pack would be an improvement in your case. weld one in your system right behind the shifter. about a 24 incher or so. it will be way better than what you got now. and the only reason i say use a welded muffler, is because they last about 80million times longer, and they usually flow SOO much better. cheap knock off flowmasters cost under 40 bucks everywhere ive seen them.
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I'm looking at a thrush "welded" muffler, it's the baffle type and the parts guy says it's free flowing. I held one (the wrong config) and it felt good and solid.
Like this: http://cgi.ebay.com/ebaymotors/Dynomax-Thrush-Welded-Muffler-3-0-In-2-5-Out-Aluminized_W0QQcmdZViewItemQQhashZitem4ced82fc03QQitemZ330402298883QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories (http://cgi.ebay.com/ebaymotors/Dynomax-Thrush-Welded-Muffler-3-0-In-2-5-Out-Aluminized_W0QQcmdZViewItemQQhashZitem4ced82fc03QQitemZ330402298883QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories)
It's really irritating that they won't ship to AK........
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Thrush brand has been a big name in the performance mufller industry for over 50 years. They will be a good choice to go with. Sound throaty on a 5.0L ford with a 351 cam in it. It may be just what your looking for.
I wouldn't cheap out on an exhaust.. if it rusts out 3 years down the road your just back in there doing it again right... Do it right, once. lol
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I'm looking at a thrush "welded" muffler, it's the baffle type and the parts guy says it's free flowing. I held one (the wrong config) and it felt good and solid.
Like this: http://cgi.ebay.com/ebaymotors/Dynomax-Thrush-Welded-Muffler-3-0-In-2-5-Out-Aluminized_W0QQcmdZViewItemQQhashZitem4ced82fc03QQitemZ330402298883QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories (http://cgi.ebay.com/ebaymotors/Dynomax-Thrush-Welded-Muffler-3-0-In-2-5-Out-Aluminized_W0QQcmdZViewItemQQhashZitem4ced82fc03QQitemZ330402298883QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories)
It's really irritating that they won't ship to AK........
I do :D... I need an excuse to go to summit I could get one and send it to you, but I wouldn't be able to get there until thursday the 11th at the earliest. I work out of an office in canton Ohio and am 20-30 minutes from summit when I am there. I have no clue what it would run to ship up there. I could get it thurs and ship possibly ship on the 12th or 13th or 16th as I think the 15th is a postal holiday.
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On Tuesday a muffler man is coming to napa so I'm gonna see if he can find one.
If that doesn't work out I'll see if summit has one and let you know. It would be less messing around if napa could come through though......thanks ;D
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Would a glass pack or a resonator be best in my case? It would be going in behind the shifter and will be used with a muffler......if I can get a muffler ::).
This, http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm (http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm) says a glasspack will go "thud" when tapped and a true resonator will go "ping", the resonator has sound absorbing material in it and the resonator doesn't. But it doesn't say what the difference in exhaust sound will be.
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I am using a 24" Cherry Bomb Glass-pack in front of the shifter on my 1.7 gasser. exhaust not sounds amazing.. I used to have a cheap muffler behind it and it sounded quiet and good at the same time.. just the glasspack alone is wayy to loud for normal standards.. but i enjoy it :)
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Lucas, I finally got napa to order one and ups blue is "only" $21, that's probably not much more than what usps would cost so I took it.....thanks though :)
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Definately use good quality,thick wall exhaust pipe ! You would be amazed at the difference,inside the car-No matter what the engine size,or vehicle.Cheap thin wall pipe,will cause resonance inside the vechicle.As stated before,the tailpipe needs to exit out from under the vehicle,after the passenger compartment,or you will also get more resonance.
I've had many vehicles,with large displacements,nice cams,flowmasters,glasspacks,ect... All have been very comfortable in the cabin,by just following these two rules.
You would be surprised in the difference,thick wall pipe makes !
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Now lets say for arguments sake I found a way to do the Gov Mod without taking the pumps top off... Yet I kept the fuel screw at or below stock settings to keep the smoke as a gray wisp behind the car, or not even there at all. I have researched and tested a method, that effectively does the WOT part of what the Gov Mod does.. with nothing more then a wrench and screwdriver.
The full throttle stop is what i messed around with, and after talking to a local yocal around here that deals with these engines/pumps as a hobby. We came to the conclusion that if you were to back to the throttle stop out all the way and then manually move the throttle arm through its entire motion to where it doesn't want to turn anymore, and then bringing the stop screw to meet it in this position.. your effectively "Shimming" the governor assembly solid. Instead of taking it out and adding springs, and making the gov mod active %100 of the time and at all peddle positions, we now only have this full fueling when at WOT.
I tested this theory on my bone stock 1981 1.6 N/A, stock intake, stock 1.5" exhaust, and stock pump. I originally had the fuel screw turned in about 1/2 turn just so i could get the thick black smoke on those hard WOT pulls, it bumped my idle to around 1050-1100 I'd say. So i backed it down to where the idle sounded closer to stock or lower, probably 900. Did the adjustment to the throttle stop and went out for a highway test.
The 400m on ramp alone showed 112-115mk/h for an RPM of 5100-5200 in 3rd with my FF trans. :P It kept pulling a little bit more but she was screaming, so I grabbed 4th and quickly (Not usually heard in context with a 1.6 N/a) climbed to and passed 130km/h. Last night I had absolutely no problems keeping up with my Gf in her 90 with the 1.8 whilst cruising the back roads.
I suggest anyone with a 1.6 N/A and bone stock pump go try this out, because I can vouch it is fueling... I wouldn't have pulled to 5200 in 3rd if it weren't :P
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lol, so you can keep up with a girl in a digi 8v? is that supposed to be cool? seems just like wining the special olympics to me.. but you never know, your gf might know how to drive the hell out of it :)
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you can keep up with a girl in a digi 8v?
In a bone stock 1.6 N/a with 900k on it? I'd say that's a fairly substantial feat. Gf is a maniac btw ;)
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it took me boost.. i still have yet to see a fast n/a diesel.
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fast compared to what though Kev? What are you comparing to? a done up AAZ? I don't claim it to be "OMFG this car is fast", just substantially quicker than stock. That substantial increase allows me to keep up with a 1.8 digi? I'm satisfied for now. lol
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a fast n/a, in my opinion, should keep up with my GTI (or something equivalent). it only goes about 120 on a straight stretch. my TD used to go 140 on a decent straight stretch.
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Why do I need to go 200-240 km/h? I dunno bout you, but here 50 over is the end of your life.. This N/a can hum along at 140 km/h easily, that is as fast as I will ever need to go. Lets stop the wiener battle. Your cars faster. mine is slow. sweet.
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no dude, thats not even what its about. not about whos car is faster. fast to me is, well, fast.. if a stock vw speedo can read it, then your not going fast. my buddies old 89 pontiac lemans would go 163 mph. and it was completely stock minus the hacked together exhaust system. im simply stating that i have never seen a fast n/a. or a quick one for that matter. i would honestly rather be quick than fast. thats where you win drag races, being quick.
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The thread is titled "a faster car". As the sometimes not so proud owner of a N/A, I am aware that they are not fast. However, with nothing more than the exhaust change I mentioned, I have made my car substantially faster. I still have one of the slowest cars on the road, and no, it's not much quicker than my mountain bike, but I can finally keep up with traffic and actually pass a car or two. For those in southern Ontario, I can now maintain the speed limit coming up the "mountain" out of Hamilton on Hwy. 6. without downshifting. Previously I had to drop to 4th and was still down to about 60 km/h by the time I hit the top. That is what I consider a major improvement, although I admit that's close to saying that I picked up $.50 and improved my net worth by half.
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The thread is titled "a faster car". As the sometimes not so proud owner of a N/A, I am aware that they are not fast. However, with nothing more than the exhaust change I mentioned, I have made my car substantially faster. I still have one of the slowest cars on the road, and no, it's not much quicker than my mountain bike, but I can finally keep up with traffic and actually pass a car or two. For those in southern Ontario, I can now maintain the speed limit coming up the "mountain" out of Hamilton on Hwy. 6. without downshifting. Previously I had to drop to 4th and was still down to about 60 km/h by the time I hit the top. That is what I consider a major improvement, although I admit that's close to saying that I picked up $.50 and improved my net worth by half.
Right on, there's no such thing as a "fast" 1.6NA, but there are some that are faster than others and I think that's what this thread is about.
If you have a NA that can keep up with a stock TD or GTI then either you're a genius or the other car is junk or isn't being drove to it's max potential.
I can keep up with most traffic easy but just a few weeks ago I lost to my Dad is his '86 golf 1.8 CIS-E, I could beat him anyday in the twisties though ;D.
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my GTI almost keeps up with my TD.
and im getting a new diesel rabbit, im going to see just how much improvement you can do with one. already have a header lined up, along with a 2.5 exhaust and a custom intake manifold. im also going to be turning up the fuel substantially. i know its not going to be a rocket, and im going to get bored and eventually turbo it, but i want to see what i can do with it. besides, i miss having a loud car.. my old blue n/a was the loudest thing ive ever driven.
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I have made my car substantially faster.
Same here, and that's what this thread is about. My N/a is QUICK. I can easily out do in town and highway traffic without struggling.. Has to amount for something, no?
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FWIW My flat red rabbit would have eaten my 83GTI after the gov mod, intake, exhaust and everything else. The GTI maybe a little quicker on take off, but it has the close ratio and the flat red rabbit had the 4 speed.
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on an N/a Lucas? sweet. I can't wait to do the real gov mod, on top of the intake and exhaust :)
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ok, so, im still sticking with the whole "n/a's are not fast" but, the n/a i just picked up will do 100 mph.. once i take it to the jetty, i will really know how fast it goes. its still a slow n/a, but its not bad off the line.. the bigger exhaust should help it greatly.
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jeez...100mph..why do you want to torture the poor wimpy little thing? Animal cruelty...
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its really not even torturing it.. it has some tall gears. only turns 4500 in 3rd @ 75 mph. and a little over 3800 in 4th @ 100..
my other rabbit saw 140+ a few times.. its not animal cruelty unless its hurting it! and both rabbits happily go that fast and ask for more.
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I suggest modding your intake to a 3" ABS/PVC setup for sure, It used to smoke like a bugger under full throttle, now its just a slight whisp. NExt is the exhaust, and GOVERNOR MOD! Gonna make this thing a monster!
(http://i299.photobucket.com/albums/mm307/J_holubek/Diesel/100_0284.jpg)
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in order of importance, in my eyes atleast..
1.) exhaust
2.) intake
3.) gov mod
in order of biggest improvement.
1.) gov mod
2.) exhaust
3.) intake
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jeez...100mph..why do you want to torture the poor wimpy little thing? Animal cruelty...
i can cruise 140 all day in my NA people say they are so slow but mine seems pretty fine. pump timing is a little advanced but that shouldn'tmake a HUGE difference
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140, thats ,like 90 mph or something isnt it? what trans you got? 4 or 5 speed? and what model?
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I had a 1984 Rabbit 1.6 NA that can cruise 140km/h a flat highway with roughly 80% accelerator pedal input. It probably was capable of going faster but I haven't tried. 4spd transmission and 400,000km on the engine. I think it may have had a slight IQ increase.
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8v-of-fury: That intake looks good. Simple and effective.
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Finally did my 3" intake; Thought I would share for others->
(http://farm6.static.flickr.com/5267/5635678507_64fabe8e77_z.jpg)
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How do you like that intake, jseeley? Notice any difference in exhaust smoke?
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How do you like that intake, jseeley? Notice any difference in exhaust smoke?
Yep, cleaner exhaust (or allows me to turn up the fuel a tad more). I also put in a K&N drop in (funny they even make one for this car) at the same time. There is a bit of a louder, deeper sound from under the hood now as well... but who notices with all the clacking anyway... :P
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How do you like that intake, jseeley? Notice any difference in exhaust smoke?
Yep, cleaner exhaust (or allows me to turn up the fuel a tad more). I also put in a K&N drop in (funny they even make one for this car) at the same time. There is a bit of a louder, deeper sound from under the hood now as well... but who notices with all the clacking anyway... :P
they dont make one FOR the diesel.
its for the mk1 and mk2 gassers..
it just happens to fit a n/a diesel as well..
same thing for the TD.. i believe you can use a digifant K&N for those..
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Not entirely sure it isn't "for" a diesel -K&N does say it fits a lot of cars -
http://www.knfilters.com/search/product.aspx?prod=33-2001
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Too spendy for me!
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Finally did my 3" intake; Thought I would share for others->
(http://farm6.static.flickr.com/5267/5635678507_64fabe8e77_z.jpg)
Which alt belt shield is that?
Sent from my SCH-I535 using Tapatalk 2
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Which alt belt shield is that?
My 89 and 91 Jetta's had those covers.
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Hey ok I got some timing questions. My car is na, with a 1.9 block and a 1.6 head.
Supposedly they have wicked hi compression or so I have heard,like its north of 25:1
I'm runnin my timing near the turbo spec, around .96.
Well it sounds like major popcorn at part throttle.
Does anyone else have this combo with this problem?
Maybe I should try na timing?
I have to dump in about a can of the silver power services Cetane boost and a gallon of motor oil to get it to calm down on like 1/2 or 3/4 of a tank.
If the hi compression idea is true then it seems like its similar to an old hi compression muscle car running new crappy gas and I haveta take some timing out possibly.
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So the thicker fuel.. makes it quieter and less poppy? Weird, usually with the thicker fuel the timing can be less as it pushes the pump pressure (thus timing) up.
Try changing it around and see what works best for you.
I think you are probably one of the only ones (I am kidding) with a 1.9 block and 1.6 head, not very common.