PAD

Looking for info from those with experience on ECU, exhaust and air intake upgrades. I think the chip is worth it, the exhaust seem questionable(although the down pipe seems worthy) and the a stock air box stage II mod with K&N filter might be the way to go.What about a tip chip. Please help

cuatrokoop

3" cat back helped the '97 out actually...

<img src="http://pictureposter.audiworld.com/28712/dsc00002.jpg">

With turbocharged engines, the less restriction on the exhaust side the better. I'm going to make a 3" downpipe for the 10vt with a highflow cat (shortie), epiflex section, and reduce it down to my current 2.5" Stebro. The Stebro will be replaced by a 3" system with a Dynomax UltraFlow. I'm waiting to see how the A4's sytem handles the winter (its coated mild steel, hence the shiny black appearance).

Audi2ptzero

this is because your moving the boost range about 200-300 rpms upwards with less back pressure.

cuatrokoop

I never noticed a decrease in bottom end...The car feels more lively now, than it did before with just the chip.

Only way to measure the difference where we are at is with the calibrated butt dyno.

Ray Khan

a chip is also a good mod. I would say in order I would do the chip first because it's the best bang for the buck. AWE usually gives you a deal on the tip chip if you buy the engine chip at the same time....add the exhaust later after hearing some. Don't go by what people tell you...hearing and seeing them is the way to decide. Some else's mild might be way to loud for you. Good luck.

Audi2ptzero

to gain top end power. It also moves the spool time up in the rpms.
Example

If you hit full boost at 2200 rpms and boost drops around 5000 rpms with a stock exhaust, if you change to a open 2.5" your going to hit full boost at 2400 rpms and hold boost to 5200 rpms, then do a 3" high flow and your looking at hitting full a little higher in the rpms and hold it even higher since there is less back pressure.
This how people tune a car for different setups. If you want more bottom end tq you go with a exhaust setup to give you more back pressure which will cause the turbo to spool up sooner but also die off sooner which is good for autox and short tight corner tracks. High flow exhaust is good for high rpm racing like drag racing since you never go below a set rpm. These are things you learn while racing dirt bikes or race karts.

JuanT

Hmm interesting.

cuatrokoop

On a small NA engine, I'd have to agree, but on a FI engine, its much less apparent...

The A4tq has reached 1.3bar absolute with the 3" system, whereas with the stock exhaust, it was around 1bar (which makes sense, because its a 1bar chip). I didn't notice any decrease in low end at all...

Audi2ptzero

Best way to see the change is to do a 4th gear pull on the fwy from 2k rpms. If your driving the car around at 3k+ rpms all the time you will never see the change down low, but take the car down to below 2k rpms then all the way to 7k rpms and you will see how the back pressure changes the turbo spool.

cuatrokoop

At very low rpms, the boost is slightly lower than before, but you are beyond that pretty quickly...

Next thing on the list is a turbo/EM/injector upgrade, and a new turbo-back 3" exhaust (stainless this time)...