Exhaust diameters.

[az20vt]

What size exhausts are people running on big turbo conversions ive got a jbs tubular under slung manifold and 2 half inch down pipe and system with one jetex rear box, turbo is td05 big16g, would 2 half inch down pipe and 3 inch system be anygood? would there be any improvment?

 

[pj1985]

Have a 3inch downpipe on my vf34. I was told 2.5inch would be good enough for IHI power but some people had said that when they went from 2.5 to 3 inch it made a noticable improvement.

 

[steevie wonder]

I have a 3" down pipe and 2.75" cat-back system, 3" would've been too close over the rear axle.

 

[caveo]

I have the same mani ( jbs stage 1 IHI ) which came with a 3" downpipe and de-cat which goes into a miltek 2.75" cat-back system.

 

[az20vt]

So would be worth going 3 inch system and leave down pipe 2 half? just havent got much room down pipe wise because of engine mount in the way,as its in a mk2 golf.

 

[caveo]

Im toying of going 3" all the way but was told id be ok as its only a little bottle neck.

 

[ibizacupra]

I had some gains when upsixing from IHIVF34 to 3" downpipe from 2.5" one
not wow, but definatelty gains.

I squeaze a 3" downpipe in my ibiza.. you could probably do this also. (same mk2 rear mount issues on ibiza as golf 2)

 

[SEATCOOBER]

i have a 3" turbo back system made abit of difference.