hi there, I have a stock 2001 audi a4 1.8t quattra with no mods but a k&n intake. The car has 140km on it and i was wondering if i can run a 3' cat back exhaust on the stock turbo? i would like to do a 3' cat delete to into the exhaust. Will i have a problem with not enough back pressure? loss of performance? am i better to run a 2.5 inch cat back?

 

They say a 3" on a stock turbo is a waste plus the drone you get is highly annoying. If you are staying stock then a 2.5 is plenty. You will notice the biggest difference with a test pipe and/or a Stage I tune. When I got my APR Stage 1 tune, it was peppier but when I installed the test pipe, it spooled 500rpm sooner and added so much more low end grunt. It also opened up the top end so it wouldn't run out of breath in the upper RPM. I am now on to a custom tune with Motoza Stage 1+ with 550cc injectors and it is quite nice to be able to finally spin the tires when it's a little damp out. The software that comes with the suite has a dyno log on it and it produces 170 awhp (approx 220 crank hp) which I'm quite happy with. Check it out since you have a 2001 with a wide band setup. It's less expensive than APR and is upgrade proof. Good luck.

Doug

 

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