MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: Liamedition30 on October 22, 2015, 07:04:24 am

Title: Which bcs downpipe?
Post by: Liamedition30 on October 22, 2015, 07:04:24 am
Just after abit of advise, booked in at bcs with nige yesterday for downpipe and decat but still unsure about either 3" or 3.5". The car is stage 1 now with all the parts to go stage 2 after the downpipe. What's people's opinions?
Title: Re: Which bcs downpipe?
Post by: DANBOY66 on October 22, 2015, 09:56:24 am
stock turbo 3" bigger than k04 3.5"
Title: Re: Which bcs downpipe?
Post by: CarlW on October 26, 2015, 11:53:01 pm
Any particular reason why not to put 3.5" on a standard K03 GTI just out of interest as i'm trying to understand more about the exhaust side of things before i make a decision on what i'd like to do myself in the near future.
Title: Re: Which bcs downpipe?
Post by: DANBOY66 on October 27, 2015, 07:08:28 am
from what i have experienced there is no point in the extra cost for next to no gain

my car made fantastic figures on 3" with sports cat (bcs) i did not see hardly any improvement fitting a 3.5" decat
Title: Re: Which bcs downpipe?
Post by: Paradox1 on December 09, 2015, 12:09:24 pm
Wouldnt it flow better if the whole exhuast system was 3.5 instead of just part of the downpipe?

Eitherway 3inch should be enough no matter what turbo your running(within reason)
Title: Re: Which bcs downpipe?
Post by: dan930 on December 09, 2015, 02:16:34 pm
What did Nige suggest?3.0 or 3.5?
Title: Re: Which bcs downpipe?
Post by: DANBOY66 on December 09, 2015, 02:57:48 pm
it will flow better at the top end but you sacrifice low down torque

like i said i was stage 2+ made 364bhp 405 lb/ft torque fitted dw intank pump 3.5 down pipe and decat and a runner flap delete

my car then made 375 bhp and 386 lb/ft torque and it feels slower due to making less torque the whole of the rev range not just at the top

since then i have fitted an anti serge turbo with clipped hot side wheel i am going back for mapping on the 5th of jan