Best exhaust for F7R turrbo

[dhay14]

what whould be the best exhaust diameter for a F7R turbo?
a full 3" system or a 2.5" system?

[MAXIBOY]

2.5 mongoose fit's with a little tweaking but a 3 inch might be better if you can get it to fit...

[drsmith1979]

All the Turbo boys here in the US whether it be Evo's, supercharged trucks, & Corvettes all stipulate 3inch tubing to aid spool up and prevent surging etc.. 2.5 is fine, but for me, i'd try 3inch or at least a modified 3inch downpipe reduced into a standard 2.5inch exhaust

[MAXIBOY]

yeah i run a 3.5 inch to 2.5 inch downpipe

[dhay14]

well i'm planning on making a whole custom 3" exhaust.
from downpipe till backbox 3" but asked myself if it would not be better off with a 2.5"

[MAXIBOY]

3 inch would be best as long as the boxes are right so you have as close to possible zero back pressure

[dhay14]

HKS HI POWER EXHAUST?
please let me know on this one, and i orderd a 3" Hi flow cat for the MOT days.