I have a 04 A4 coupe that has 10,000 miles on it, I got it used a couple of months ago. I found it to be sluggish especially on the low end so I planed to make some performance mods. Fortunately I decided to have it dyno tuned first. The guy at the shop put it on the dyno and made the first pull then got out and told me something was wrong with the engine. The numbers for the pull were 174 HP and 180 Ft/Lbs torque at the rear wheels. It will be going to the local dealer on Monday, it’s still under warrantee, but I expect to have to fight with them. This may turn out to be the cheapest horsepower improvement I have ever made.

 

174/180
Umm yeah I'd say it would be a LITTLE sluggish.

Hope the reapir is something simple.
Please let us know what they find out.

 

I got the vette back from the dealer and WOW needles to say this car is no longer sluggish. I took it to the dealer and I must say they were great. I showed them the dyno results and first they laughed then they patted me on the back and said don't worry. First they re-checked fuel pressure it was fine. Then they checked back pressure on the exhaust system, it was fine. They did a compression check and found no problems. They told me they felt that it was a problem with the PCM either it was bad or the program had been messed with. I told them that I had changed the differential from a 2.73 to a 3.42 and had mailed the PCM to a "tuner" to have the shift points changed. They check the PCM program and told me that their machined was telling them that it still had the stock program. They re-flashed the PCM back to stock just in case and took the car for a test drive, the change was obvious. I took it by the local Dyno shop and he changed the shift points for the 3.42 temporary until he can schedule a slot for tuning. Too be honest I'm not sure I need any more power, any time I push hard on the accelerator the tires break loss. needless to say the "mail in tune" was a bust. I won't say who I used but they are not a supporting vendor. The Dyno shop was very helpful and the dealer didn't charge me a dime for the work they did, they called it warranty work if anyone needs a Dyno shop or dealer in the Florida panhandle let me know I can make a good recommendation.

 

I bet that thing does feel alot different now. Glad to see it's being worked out.

 

They actually said that?

 

The actual statement as I remember it was " the back pressure test was okay"

 

You should post the tuner AND the dealer.

 

Why not? It's not uncommon for catalytic converters to clog up.

 

Wow, that's a good dealship! The one's I've gone to would have charged me for the time, a new PCM, new tools, found out I needed a carb AND fuel injector cleaning, a brake system flush, new automatic trans fluid for my M6 trans, and an oil change. Too bad they are 1200 miles away or I'd go there for service. Nice find and congrats on the fix.

 

I very recently found a major problem with my car by checking the back pressure and temp of the exhaust. This is why I don't like true X-pipes. It would of been much much harder to pin down the problem if I had an X-pipe on my exhaust system.

First of all, my car has a STS TT system installed on it. Since I and some help from some great friends did the install, I know the car pretty well.

Last week my car was running great so I decided to take it to the strip. Well as luck would have it, on the first burnout pass in the water box, the car sputtered pretty badly. I ran a lousy 12.6 at 116 mph.
the second pass was 12.8@114. I knew that I was losing boost so I packed it up.

The next day I disassembled the BOV and checked it. I checked the wastegates and ALL the sillicone couplers on my car. This requires taking off all four wheels and inner fender panels. All looked good? .

SO I finally checked the ehaust color in the tail pipes and I could see one side was leaner than the other. I held my hand over both tail pipes closely and found that one side had a very slightly less "output" than the other side. The side with less pressure also ran cooler? . So I hooked up my trusty Ease scan program and sent it off to my tuner ans he and I could not find anthing wrong and that both cylinder banks were running well???. The fuel pressure and O2 readings were spot on. Fuel trims and temps of coolant were also perfect with no difference on wither bank. Armed with this info, I removed both sides of the turbos exhaust and spun the blades by hand, they both were perfect. I decided to check the cooler running turbo first was my first thought, upon removal, I found the intake side of the turbo had a piece of flattened sheet metal in it. I reconized the part as part of the OEM asbestoes gasket between the ehxaust collector flange that connects to the H-pipe. The gasket looks like a doughnut about 1/2 inch thick x 2 1/2 in. diameter with a sheetmetal ring on the I.D. This sheetmetal ring is bonded from the factory to the gasket, but failed due to higher exhaust temps while being boosted.

Yes a exhaust back pressure test can reveal a problem. Hmm... I should post this finding to STS owners who have stock exhaust manifolds or running shorty headers.

 

that's great you got it fixed and now you can probably save that mod money and put it towards something else until you get comfortable with the new found power.
Honestly though, you should put the money into an interest bearing Mod fund. As very soon that new power will not be enough and you'll be ready for more.