ok i want to do exhaust, but i dont want my cat in the engine compartment.... is it possible to put a test pipe, to downpipe, then the cat under the car where it should be to a custom catback?

 

Where it "should" be? Ha... "Should" according to who/what? I'm sure the crazy germans had reason for where they put it, but it can be moved further down, its just the 02 sensors wont reach without splicing in more wire. You do want the 02 sensor as close to the engine as possible so it is making on time corrections.

 

if you got rid of the second o2 sensor and could find a place to fit the cat under the car (in place of the second resonator?), it could work. you may be taking away from the efficiency of the cat, moving it farther from the engine means its going to be cooler and possibly not burn as much of the exhaust as before. if you have to pass emissions i might not do this.

 

yea i need to pass emissions... and i want a nice exhaust.. i guess a testpipe is out of the question then....

 

What is wrong with having the cat in the engine compartment though? You can still get a cat back or down pipe back exhaust.

 

yea, but my engine bay wouldnt be as hot as it normally is

 

i dunno, if anything i would think it would be hotter with a test pipe then with a cat. the cat has a heat shield around it to reflect heat back into the exhaust stream. a test pipe would just radiate heat into the engine bay. thats how it would work in my head anyway.

 

eh.. maybe ill just get a hfcat and get the borla i wanted

 

exactly correct... that is a reason why Audi uses some of the most advanced technology in engine design.

 

you mean most expensive technology