nissan primera p11 gt bhp increase help.

Me and Ben both run 3", Internet hearsay doesn't always work in reality

It's what works in reality though, hence the Internet hearsay not being true

The fella that built the exhaust told me it was too big, as would any other company making exhausts, but it had been proven time and time again on VE's to be beneficial, Iv even known people use them on DE's without complaint. Problem is until people try things and dyno it back to back you never actually know for sure what works and what doesn't, mine felt miles better with a 3" system compared to a 2 1/4" system, maybe 2.5" would of been a compromise but considering my VE makes a bucket load of torque low down and screams at the top there's no real need for the compromise, before its even getting started it makes more torque than a stock de ever does

mariocinq wrote: for NA 2 1/4 cat back is more than enough, only need 2.5 if planning turbo as you will lose a little power and engine responce due to lack of back pressure. unless your NA is runnng way over 250bhp then you need a 2.5inch cat back.

mariocinq wrote: for NA 2 1/4 cat back is more than enough, only need 2.5 if planning turbo as you will lose a little power and engine responce due to lack of back pressure. unless your NA is runnng way over 250bhp then you need a 2.5inch cat back.