Hi. Which kind of power levels you guys are running with 2.5" exhaust?
I have now straight 2.5" pipes when the flaps are open. Is it good for up to 650 hp?

 

If your turbos arent able to reach the programmed boost pressure, you will know. Its a tight call.

 

Should be ok for 650hp, but 3" will run better

 

To not make set boost you would have to have really hit the wall with restriction, I'd think a flow restriction would hurt power long before that. You could probably do some math to figure out flow. Do you have any reason to believe you've hit a choke point with your existing setup? The flaps and mechanism will probably cause some restriction even opened so consider that. Pretty sure my exhaust is 3inches so I'm not much help with real world data I'm afraid...

 

2.75 " needed.

 

you need to open it up and let it breath