v6 cat back exhaust question

[randall93]

So im thinking i'm gonna do a custom cat back exhaust myself

i have a FWD v6 passat. the "custom" exhast is going to start right before the suitcase. It's gonna start right after the two exhaust pipes come into one.

for clarification the stock exhaust has two flex pipes into two cats into 1 pipe, into the resonator (suitcase), then into a muffler then out the back.

im going to replace the resonator with a 2.5'' pipe with two 90 degree turns into a 22'' straight pipe (possibly a glasspack, thoughts?) then into a magnaflow or borla muffler.

2 questions: what are everyone's thoughts, and if i went with a 3'' straight pipe and muffler would the engine still run properly or would there be a back pressure problem?



for reference this is sort of what i'll be doing except my straight pipe will be after the 90 degree turns.
http://www.passatworld.com/forums/68...k-exhaust.html

[bnortron113]

i cut out the suitcase and am running a glasspack out the back. sounds great to me. theres a good youtube video with dual glasspacks (4 motion)

http://www.youtube.com/watch?v=c_GADqpXFjs

[koidragon1980]

i just did a similar setup to my v6. i had the y-pipe after the cats cut and moved closer to the cats. from the y i'm running a 28' long 2.5' inlet/outlet magnaflow glasspack in place of the stock 2.25' pipe that runs to the stock suitecase (which i removed). in place of the suitecase running from the glasspack is 2.5' piping which bends around and out to a borla pro xs muffler with 2.5' inlet and dual outs.

the sound is perfect for me. smooth and aggresive when you want it to be, but civilized when you're just going easy or cruising.

i ran the borla without a glasspack or suitecase for a few months. sounded amazing and very aggressive, but it droned too much for me between the 2-3k rpm range. adding the glasspack as a res in place of the stock piping after the y-pipe a good compromise of loosing the drone but keeping some of the aggressive sound when pushing things.

i'd stick to a 2.5' diameter. 3' would be ok but a bit of overkill unless you supercharge it. i think things would run ok with 3' but you'd probably get more drone, more noise and some annoying crackles of rasp unless you run both a muffler and a res. just a straight pipe with a glasspack would make things constantly scream at you.

while i enjoyed the sound of the 2.5' with just a muffler and straight pipe, i think the car is running smoother and pulls a little harder after adding the res. of course the smoother aspect could just be the fact that the drone isn't constantly vibrating my floor and seats anymore. but she does feel a little "zippier" on acceleration after adding the magnaflow glasspack as a res.