I just ordered a highflow catback anybody know on about what kind of a difference it will make? hp? tq? oh and i ordered the mopar PCM

 

one more question wich would you all think is better unorthadoz underdrive pully or af/x?

 

What brand cat-back? The underdrives are about the same.

 

You'll gain about 3-5 HP on the muffler assuming you've got 2.5" or 3" tubing the whole way down. As for the Underdrive Pulley, I'd stay away from the 2 piece unorthodox design. Word from the wise is that they 2 pieces tend to come apart. Stick with a 1 piece design. Essentially, they all do the same thing. Lighter pulley and less power given to the acessories.

 

yeah considering most ppl just buy a muffler and slap it on there stock exhaust doesnt really help you need at least 2.5 or 3 inch piping all teh way back in the first place as stated above by whyte

 

Even bigger piping doesn't help if you still have the factory cat (2.25" outlet) and that stupid bend/kink right after it where the O2 sensor is (which is not replaced by any of the current aftermarket systems). All of the gains on a cat-back system are just from the muffler. Maybe I'll ask Vitor to post up the dyno results proving it... again...

 

if you don't have emission laws or can get around them, just junk the cat all the together and put a high flow res pipe on there, much better sound and performance. and will add to the hp-tq gain. i'd also sugg, saving up for a header.

 

I have 2.5 piping on my pacesetter exhaust . A while ago I hollowed out my cat some but got really tired of pounding it out. I bought a megan racing hi flow cat and noticed some good gains easy install too. I would go with the modernperformance pulley