2.5 piping how much BHP
- Thread starter jam
- Start date
GTti
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None.
Sharp angles can create pressure drops, but you're not likely to experience any difference with a change in pipe diameter.
Larger diameter piping is more beneficial when increasing turbo / compressor size.
In saying that I think there is good reason to keep piping small with smaller turbos the same reason why you don't need to be excessive with exhaust pipe size. You're more likely to affect torque and response by keeping the piping smaller, it can be filled quicker (reach full boost) and i'd say it'd help with velocity also. Daihatsu kept the throttle body on the GTti really small to help this, as the 3 cylinder engine tuned for the higher rev range, it's sluggish without the turbo low down.
Become a problem / restriction with a larger turbo though. So everything needs to be in moderation.
Sharp angles can create pressure drops, but you're not likely to experience any difference with a change in pipe diameter.
Larger diameter piping is more beneficial when increasing turbo / compressor size.
In saying that I think there is good reason to keep piping small with smaller turbos the same reason why you don't need to be excessive with exhaust pipe size. You're more likely to affect torque and response by keeping the piping smaller, it can be filled quicker (reach full boost) and i'd say it'd help with velocity also. Daihatsu kept the throttle body on the GTti really small to help this, as the 3 cylinder engine tuned for the higher rev range, it's sluggish without the turbo low down.
Become a problem / restriction with a larger turbo though. So everything needs to be in moderation.
Monkfish
Member +
3"? On the Starlet? What on earth possessed you to do that? 3" is ample for an Impreza, 2.5" is borderline on a Starlet, regardless of turbo size.
To note: The Bitch has a 2.5" system and pulled 179bhp at her last dyno run. CT9a turbo.
javieringo1
Member +
wouldn't 2.25" work better?
sorry mate its exhaust pipe I heard 2.5 piping will prevent boost creep and better turbo response am using CT 9 Hybrid. with the CT 9Hybrid I feel my car bid hesitating around 150 to 180 where as the stock one doesn`t. Any advice please help.car specs Tong CT9 H, no airfilter ,decat pipe, stock mani, Stock fuel pump & regulator 0.85 bar boost. please help. Thanks
Tony Harrison
Member +
Age old statement coming up.....
"Replacing stock manifold would help no end with a couple more GGs at your disposal".
"Replacing stock manifold would help no end with a couple more GGs at your disposal".