What does a Test pipe actually do? sorry i am a nub when it comes to actual knowledge of performance parts ... i have a 3" cat back exhaust with a after market muffler and i was told not to clean out my cat .. but i want it to be louder.... what should i do? will a test pipe do this and if so what kinds? does it add performance?

 

test pipes will make it louder yes

it will be a petty decent performance mod yes

it will make your call smell bad yes

it prolly wont pass emissions yes

unless you go to a shady spot and pay them off....yes

 

Test pipes bypass the cat completely. They aren't legal for street use even though a lot of guys here use them. Just be prepared for the consequences if you get caught.