I'm exploring a few modifications for the spring season. I've got a few things in mind, but I want to know what other people might think as well.

Choice 1 is a chip. An instant 65-70 hp and a similar increase in torque. I like the idea of the chip, but of course there are warranty issues to be concerned with. Cost is about $1150 for a complete ECU.

Choice 2 is an exhaust. A full cat back exhaust, 2.5 in, mandrel bent T304 stainless-steel. Complete parts and labor with 2 mufflers, 2 resonators and crossover pipe will come to $900. Installation shop (top notch place) says that it should be good for about 10-20hp on this car, but the weight savings will be about 20-30lbs also. The combined effect would amount to about 25hp increase.

Obviously, the chip delivers the most hp per dollar, but the exhaust won't void my warranty or place any undue stress on the rest of the drivetrain. I've always complained that this car needed an additional 20 hp to make it "perfect" and the exhaust would get me where I want to be without worry.

All those who have done one or both of the above, please feel free to chime in, I appreciate any advice that can be given.

Thanks in advance.

 

there a drop-off? If all you're looking for is that extra 20 HP or so, then the exhaust seems the way to go---although I disagree with your statement that it won't affect the warranty. To the extent that any issues arise that might conceivably be related to the modified exhaust, your dealer (due to AoA looking over their backs as the compensating party) might allege that those issues cannot be repaired under warranty.

The warranty related issues with a chip are obviously more extensive. Since the chip would provide you with substantial "excess" HP (that is, gains that you don't feel you need), and since the warranty related issues will cause more heartburn, agony, etc.---at least, they would with me---I'd go with the exhaust IF the HP gains are real.

 

If you chip it, it seems you are willing to deal with the ramifications of a blown turbo our something related to the upgrade. the only thing the extra ecu does for you is to not tip off the dealer that you have a chip.

It's not that cut and dry to put the spare ECU in and run it to the dealer. There are certain codes that need to be erased prior to sending the car to dealer, or they will know for sure it isn't the original ECU. There are also Immobilizer issues that I think APR has worked out but I'm not too sure. The chip, sans new ECU should run about $600 maybe plus any other EMCS programs you want to run(from APR).

The way I see it is this, if I chip, I acccept all the risks involved with chipping. As far as putting more stress on the engine, during normal driving, the chip doesn't necessarily put any more stress on the engine than normal. It's pushing the engine hard where you will see the biggest difference.

My car is leased and I figure to take the chip out prior to my returning the car or selling the car outright and taking it from there.

Good luck.

Dave

 

As I understand it: On a NA (non-turbo) car the gains are real, but usually only at the high end of the revs.

On a turbo car this can be different because if you can free up the exhaust you can perhaps get the turbos to spool up quicker. This produces additional HP at the low end. These gains are also real, but note that they don't show up on a dyno since dyno plots are usually made at a steady state or during slow acceleration and this additional HP mostly only shows up during rapid acceleration.

Either way, the gains are real, but they are usually overstated by the manufacturer.

Jim Will: if the exhaust is good for 10-20HP, then the likelihood of the effect of the exhaust being 25HP is low. Since you are only dropping 0.5% of your overall weight, so an effective HP increase of 2%-6% (5-15HP) ranges from not likely to not gonna happen.

Audi will tear you a new one over your warranty with either mod, even though a properly constructed exhaust shouldn't significantly increase the change of breaking.

 

Obviously one upgrades the spare ECU so the car has the original ECU when stock... and of course an '00 has no immobilizer issues.

I fully agree with accepting the risks of a reprogrammed ECU, and applaud your upfrontness about this.

I'd still suggest getting a spare ECU to avoid any issues with non-drivetrain problems. Some dealers have been known to blame power window problems on a modified engine computer, so having the spare will let you sidestep those hassles.

 

and when you are starting to get the itch to "need" more power again, next year or so...get the chip...by then your warranty will probably be close to expiring anyway

 

Rev'd up quicker and kept pulling.
About the warranty, I aked my dealer and they said, "As long as its from the cats back and that it bolts right up to the existing mounts, then they have no heartburn with it". But if any problems with the exhaust itself, that would be my nickel. Course every dealer is different. Jim, ask your dealer about a catback exhaust that bolts right up to the stock mounts, see what they say.

 

chasis dynos from Superflo, Dynojet, or Mustang. Besides, a steady state measurement will only indicate the energy required to overcome the resistance at that spped/RPM.
Every chasis dyno I have performed, witnessed, and paid for occurs as a full throttle "pull" in fourth gear to maximum revs. No steady state, and absolutely no "slow acceleration". On my mostly stock 99 Cobra, they take approx. 9 seconds! That is 2000 RPM to 7400 RPM, accelrating the drum as as fast as it can, in about 9 seconds. It truly is amazing to behold.

 

That's what I want, but I can't find one that doesn't require bodywork.

 

the 02 cars have straight through "design" mufflers. There is nothing inside of them, the exhaust pipe goes straight through the case! Therefore, you may experience some HP gains froma larger exhaust with free flowing, more HP efficient mufflers. I would question any quotes of greater than 10 HP per muffler x 2 mufflers = 20 HP increase! Would Audi really use that enefficient of a muffler design, then change to the free flowing, straight through design for 2002?
Remove the resonator as soon as possible, today if there is a muffler shop nearby. You will appreciate and feel it immediately, but I seriously doubt if you will hear it. Especially if your mufflers are chocking 20HP of sound! It is amazing how this simple mod improves the resonse of the bi-turbo motor.
Yes, a larger diameter exhaust "system" will flow more air. The pipe used on my 02 ranges from 2", down to approx. 1.7" An upgrade in tubing size would be a benefit over stock. The cats on my 02 are mfg. by Liestritz, a very well known exhaust mfg. in Germany. Would larger, high flow cats help? Probably more than the entire exhaust if the stock ones constrict the flow. Look at all the high flow cats available for American cars. It is all the rage, and the next documented and proven step to making more HP. The high flow cats (Basanni) on my 99 Cobra were worth 17 rear wheel HP alone! That's 20 Hp at the crank! 10 Hp per cat. Which is more restrictive, a cat or an Audi muffler?
Your delima: chip it if you are going to chip it. I will soon chip mine. I would do the exhaust, but in aluminzed steel for approx. $120.00 - $140.00 with some very good, high flow mufflers like Borla XR-1 #40941 12" long, 2-1/2" inlet/outlet, all stainless. Actually, I would not have any mufflers. If it is too loud, add the mufflers. If this steel system does what you want, duplicate it in stainless down the road with the same stainless mufflers. If it does not, you are out the minimum amount of money.
I would love to hear everyones feedback as I am still learning about these cars and engines. I just discovered a 4 wheel dyno nearby and plan to quantify all the changes I make. This way, we all willknow what adds torque/HP.