EGR Delete = More HP

Is this correct? Vehicle in question 97 Jetta TDI - Vin # 3VWPL7AJ7EM621856

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No, it will not. Under normal operation, on a stock engine with everything connected and working properly, a request for full output via your right foot will cause the ECU to shut the EGR off completely anyway.

If you want more power, on that engine, the PROM chips in the ECU get swapped with different ones. In many cases, these aftermarket chips have software that does not use the EGR, but that is not where/how they add power. They add power by increasing boost, fueling, and a more aggressive timing map.

Problem is, on the early engines like that, with their teeny weeny wastegated turbo, you end up with a seemingly lock step increase in black smoke with any power adding. At least that was my experience, but things may have changed. Honestly the newer TDIs kind of left any development with the older engines in the past. Most folks with the older cars like that are just trying to keep them working amidst parts being no longer available, the bodies falling apart and rusting away, and the interior falling to pieces. If you have a really nice example, I'd be more worried about keeping it nice, enjoying its virtues in stock form (which in the light weight A3, the 90hp AHU is reasonably peppy and very frugal).

I enjoyed my A3, and to be honest I think I liked it more when it was 100% stock under the hood.

A clean EGR and intake definitely increases HP.


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oilhammer said:

No, it will not. Under normal operation, on a stock engine with everything connected and working properly, a request for full output via your right foot will cause the ECU to shut the EGR off completely anyway.

If you want more power, on that engine, the PROM chips in the ECU get swapped with different ones. In many cases, these aftermarket chips have software that does not use the EGR, but that is not where/how they add power. They add power by increasing boost, fueling, and a more aggressive timing map.

Problem is, on the early engines like that, with their teeny weeny wastegated turbo, you end up with a seemingly lock step increase in black smoke with any power adding. At least that was my experience, but things may have changed. Honestly the newer TDIs kind of left any development with the older engines in the past. Most folks with the older cars like that are just trying to keep them working amidst parts being no longer available, the bodies falling apart and rusting away, and the interior falling to pieces. If you have a really nice example, I'd be more worried about keeping it nice, enjoying its virtues in stock form (which in the light weight A3, the 90hp AHU is reasonably peppy and very frugal).

I enjoyed my A3, and to be honest I think I liked it more when it was 100% stock under the hood.

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Thank you. This will be my first diesel and I'm trying to sort through the crap info I'm getting before I start working on it. Is there anything you would recommend doing to a 250,000 mile engine besides the obvious chains, bearings and gaskets?

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There are no chains on that engine thankfully.

Does it run OK? A well cared for AHU at only 250k miles shouldn't "need" anything in terms of major mechanicals.

Oil and filter change every 10k miles.

Fuel filter every 20k miles.

Air filter every 40k miles.

Timing belt every 60k miles.

I would want to be certain the alternator clutch pulley is working properly, that the newer style crank pulley/balancer is on there, and that the front sprocket and crank snout are in good order, and maybe inspect the water pump and housing and coolant hoses for any leaks, as well as the injection pump.

oilhammer said:

There are no chains on that engine thankfully.



Does it run OK? A well cared for AHU at only 250k miles shouldn't "need" anything in terms of major mechanicals.



Oil and filter change every 10k miles.



Fuel filter every 20k miles.



Air filter every 40k miles.



Timing belt every 60k miles.



I would want to be certain the alternator clutch pulley is working properly, that the newer style crank pulley/balancer is on there, and that the front sprocket and crank snout are in good order, and maybe inspect the water pump and housing and coolant hoses for any leaks, as well as the injection pump.

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I'm getting the car this weekend from my father in law. He got it with a major oil leak and no maintenance history. He fixed the leak and is giving to me for a daily after my jeep went down. I usually work on gas engines so I have a basic idea but idk details

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oilhammer said:

There are no chains on that engine thankfully.

Does it run OK? A well cared for AHU at only 250k miles shouldn't "need" anything in terms of major mechanicals.

Oil and filter change every 10k miles.

Fuel filter every 20k miles.

Air filter every 40k miles.

Timing belt every 60k miles.

I would want to be certain the alternator clutch pulley is working properly, that the newer style crank pulley/balancer is on there, and that the front sprocket and crank snout are in good order, and maybe inspect the water pump and housing and coolant hoses for any leaks, as well as the injection pump.

Click to expand...

I keep hearing they have the same I-shaft bearing problems the 1.6 had.
They need to be renewed after that many miles.
I usually see them go around 150,000 miles on the 1.6s.

No hp gains can ever be had by this delete. Cleaning things and making them back the way they where will reator maybe 1 or 2 hp but that's honestly a rounding error. Same goes with mpg. No change other than what you should get if it worked properly.

fatmobile said:

I keep hearing they have the same I-shaft bearing problems the 1.6 had.
They need to be renewed after that many miles.
I usually see them go around 150,000 miles on the 1.6s.

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Pre-TDI VAG diesels with bad I-shaft bearing wear are from overtightened belts. Otherwise, they last a very long time. My own '91 had 437k miles on it when I tore it down, and the babbitt was bearing worn off the loaded side of the front bearing. I've owned lots of these, and worked on many, many more.

The early TDIs have an auto-tensioner, so unless you do not pay attention to the indicator, you cannot overtighten those belts. However, they DO have an increased load already, as the DI pump works at higher pressures. This is why the upper roller was added, because otherwise those belts will "sing" as that long distance from the cam to the pump will set up a harmonic resonance.

Still, with proper care (correct oil, good filters, etc.) the I-shaft bearings normally hold up OK but certainly when approaching 300k miles of use is worth a closer look. If you remove the I-shaft pulley, and remove the retainer plate, you can wiggle the shaft around and get at least a bit of an idea of how much if any excessive play is present. If you actually want to SEE the end bearing, though, the shaft will have to be pulled out. You can pull the shaft out enough to view the bearing (barely), but you cannot easily remove it completely from the engine while the engine is in the car. Much less get the extractor/installer in there to change the bearings (there is another down at the other end of the engine). So at that point, you'll be pulling the engine out.

oilhammer said:

Most folks with the older cars like that are just trying to keep them working amidst parts being no longer available, the bodies falling apart and rusting away, and the interior falling to pieces. If you have a really nice example, I'd be more worried about keeping it nice, enjoying its virtues in stock form (which in the light weight A3, the 90hp AHU is reasonably peppy and very frugal).

Click to expand...

Wise words right there! Save the upgrade money to fix whats broke. So many car come through my shop with 1500 worth of wheels, big expensive stereo systems, lowered with "coil-overs" but yet they cant afford the blend door repair or the TB is overdue.

I just picked up a 1998 A3 - the interior is extremely clean, there is no rust and it had 275,000km (160k miles). That is the plus side. The downside - it needs rear wheel bearings, struts on all 4 corners and someone decided that while deleting the EGR, they would also delete the intercooler and related sensors. They put in a pipe directly from the turbo outlet to the intake - and have an intake where the 90 degree bend is bolted so it can be reversed - they have it so you get the shortest route possible...I've never seen anything like it.

They also ran a straight pipe back, and removed the cat in the process.

I'm lucky - I drove my last 98 A3 to the wrecker and it's still there and was unmolested so I have all the parts to put it back to stock.

What I found with upgrades was to run a mild tune with stock injectors. I have PP520's from Drivebywire still and could put them in but will likely just go with the tune since I have the chips already.

The car handles so well with the Bilsteins, it fits my tall body and there isn't a lot to do for maintenance.

Keep it simple, Bob