Originally Posted by Beyond the Dyno
You should go and pick up a copy of the February 2008 copy of Option Magazine. Hiro the editor in chief just sent me a copy because thereís a feature of Cosworth in it. Aside from the fact that thereís a bitchin feature of Cosworth in it (and a picture of yours truly with a stupid ass smile), the main focus of this issue is the R35 GT-R. Thereís also a R35 GT-R catback exhaust test in it where some shop fabricated a titanium catback exhaust and the car made 507.9ps (500.95hp) at the flywheel. Granted, this test was conducted on a Dynapack so it probably read 5% or higher than any other dyno, but the gain of 22ps is for real. If you canít do the math, thatís 485ps from the factory which is pretty god damn buff already considering the car is rated at 480hp at the flywheel. The boost went up by 0.1kg/cm^2 (1.42psi) due to the reduced backpressure, but this also tells you that the car has some serious potential from the factory. By looking at this exhaust I can guarantee you that itís louder than hell so I wouldnít expect a 22ps gain on a production catback exhaust though.
It looks like Nissan calibrated the fuel map to go leaner after peak torque. This is done to increase peak horsepower and is probably fine at low boost and horsepower levels where the cooling effect of a rich mixture is not necessary. Keep in mind that Nissan is shooting to compete with supercars so they need that peak horsepower number so rich baller dudes can tell their buddies, ďIt makes 480hp. Thatís the same horsepower as your Porsche 997 Twin Turbo for $60k less!!!Ē. The R35 is buff.
Here's the link again: http://jdm-insider.com/Blogs/Eric/?p=540
Clearly he's talking about from the flywheel.