i have been doing some reading on this topic and i still can't find out witch is better i want to put some long tube headers in my 95 z28. wat is the best way to go.

 

Your '95 has a downstream oxygen sensor?

 

95s only have 2 sensors and you cant sim them you need a pair of 12" extensions

 

Yeah two cats and two o2's. one of my cat on the driver side broke into peices and now my car is running rich.

 

What the other two guys were trying to say id O2 sims are STRICTLY for the O2s behind the cats starting in 96.

If you put them on the 95 in front of the cat best case is it wont run right, worst case the false feedback could cause incorrect fueling to the point of blowing up the engine.

The O2s in front of cats are so the pcm can monitor part throttle air fuel ratio, the ones behind the cars on 96 and later are just to check operation of the cats and those are the ones guys put sims in place of BUT there is a pretty good argument to be made for programming them out instead on those cars. Less cost and complexity.

Not to be a jerk but if you thought you needed O2 sims on a 95 you need to NOT be buying parts for the car just yet. Keep reading and get a better understanding first.

 

I guess you have a California emissions car. Otherwise your 95 A4 would only have one cat. If you have a bad cat, you need to replace it.

 

thanks guys i keeped on reading and yeah its only for 96 and up but it dont hurt asking thanks