What size exhaust bore

Running somewhere in the region of 360 to 380bhp in my mk3 golf 20v, what size bore do you guys recommend and why??

Cheers

 

planning on running my existing 2.75" miltek with a 3" DP when I fit my 2871 and 2.0l block.

 

i would say 2.25 for a respectable tourque curve (will limit power tho) , however if your after balls out power !, then 2.5 and above will do the job .
might be tricky trying to fit a 3" system tho .

 

Surely with 360-380bhp your exhaust is working ok as it is?

 

Yes I have full 3" right through but the noise and drone is horrid, want something quieter

 

just get a jetex 2.5" system , and you'll be fine

 

exhaust tuning in a turbo isn't like NA (or even SC).
restrict the exhaust downstream of the turbo and you won't get a "better torque curve", you will get higher back pressure, reversion, slower spool, lower torque and lower power.
what turbo/software are you running?
you running a cat? what DP?

I would get a resonated milltek again if it was my choice. its 2.75" so you won't lose too much flow, pricey but they are quiet compared to some bigger straight through systems.

 

Saw the TSR Jetex thread, just bought a 2.5" 2-box system, mild steel (it lives a pampered life) and plain tailpipe.

I previously asked Ben Leach at Qpeng what he thought for my set-up (290bhp Mk2), he said that 2.5" was good for noise with hardly any losses over 3".