Originally Posted by Boosted Performance (Post 2017299)

The car made 550whp even, and please note that the actual boost pressure at max HP is about 9psi (10psi at 6,000rpm and falling). The reason the boost is up in the early rpms was due to having a manual boost controller. Because it is a manual boost controller, there was no way to controll boost in the upper rpm's (like haveing an EBC and the option to increase the duty cycle). So it was turned up so that we can be as close to 10psi as possible at max power. As a result the boost was up to 12psi at 4500rpm.

http://i18.photobucket.com/albums/b1...scan0001-1.jpg



The reason I say the 2.5" dual will make a lot of power is because of that graph. There is no sighn of it tapering off. It is just a nice linear line, with no dips, and no falling off at the top.

This is a Boosted Performance single, twin scroll turbo with a Precision 6266 billet T4 1.0 a/r. 3" down pipe to a Y-pipe going to the F.I dual 2.5" exhaust system with 14" resonators.

Originally Posted by theDreamer (Post 2018202)

Did you stop at 7k RPMs? Because after there is a drop off.

Originally Posted by Boosted Performance (Post 2018226)

This would be a result of pulling timing, falling boost and flow limitation of the 1.0 a/r turbine housing...nothing to do with post turbo turbo exhaust.

Originally Posted by Mr.Squeeze (Post 2018322)

Sound's like the 6266 is comarable to the GTM stage 2 that's real nice.

Originally Posted by Boosted Performance (Post 2018336)

Yup, maybe even a bit more power because you can go up to a 1.32 a/r housing with the 6266. These egnines breathe so well, and rev very high....turbine housing size is key.

Originally Posted by Mr.Squeeze (Post 2018350)

That's even more impressive, I learned the hard way housing size on my build not looking forward to swapping mine.

Originally Posted by SS_Firehawk (Post 2018644)

Just to clarify to everyone who thinks loss of back pressure means loss of low end tq. Your wrong. Because you have an enormous tube for an exhaust, it reduces the velocity of the exhaust leaving the motor. The domino effect is it reduces the scavenging effect or more simplistically, a vacuum effect of the exhaust assisting in pulling the gasses out of your cylinder. At low rpm, it's crucial in developing low end tq. The higher rpm you move up the power band, the less effect it will have because now the exhaust velocity is up to an acceptable point to continue scavenging. Exhaust size is critical to the amount of air your trying to move. A 3" dual exhaust will really only benefit you of your pushing 650-700hp at the crank or higher. 2.5" exhausts are perfectly sized for our motors until you start pushing some serious power.