Ok, so i just installed headers about two weeks ago, i have a straight pipe instead of a cat and my rear 02 sensors are still hanging (haven't got a CEL so they said that they don't want to mess with the car) My question is, not having those rear 02's in is that affecting my performance? the reason i ask is last night i was out with my buddies one has a GLI the other has a GTI 1.8t, we raced and i lost, they pulled on me in every gear, when i had my y-pipe with the exhaust leak i beat these guys, now i can't so whats up? Any help would be greatly appericated I got home pissed and wanting to sell my car.

Another question: is not having those 02's in detuning my car?

 

Have you dyno tuned yet? It's probably running super rich in the higher RPMs. I wouldn't be upset till you did that.

It's not the secondary sensors. All they do is tell the ECU whether or not to throw a code. They aren't used for tuning at all.

You'll get your code soon. It took mine almost 2 weeks and a few hundred miles. Others have had the same thing happen.

 

No dyno yet, im getting one in the next couple weeks

 

rear o2 doesn't affect performance, just tells the car when to throw a cel

 

I would see what your AFR is first, I would think it is just a tuning issue.

 

every car is different but i was running 11:1 a/f after 5k rpms with my headers as opposed to almost 13:1 flat with the old cattman y pipe.