| Phimosis |
03-19-2010 03:15 PM |
RE: noise made by vortech V3 blower; On Youtube there are quite a few extended user videos of V3 blowers on G35's. In car, out of car, stock exhaust, aftermarket exhaust. It's a good starting point. I'm sure Stillen wants to get videos up on Youtube for promotional purposes just as badly as we want to see them.
RE: Parasitic drag of S/C and revving of engine; Revving of engine is based on (net torque) / (moment of inertia). For those that are not familiar with moment of interia, it is the rotational mass and how far from the rotational center the mass is placed. increasing the distance from center increases the torque needed to accelerate the object. In the case of a SC engine, the bulk of the rotational mass is the crank, pistons and rods. The moment of inertia, though is heavily influenced by the flyheel because of its large diameter. The moment of inertia of the supercharger is low because of it's small diameter, so the supercharger's biggest imapact is on net torque, which is (torque made by engine) - (parasitic loss). With all of this said, off idle the SC is not making boost so net torque is lower than stock and decrease the rate of revving. by 2,000 rpm or so the blower will make some boost and net torque will be higher than stock and boost will build to redline, so the increase in net torque over stock will increase to the redline as well. The end result: near stock revability from idle to about 2,500 rpm, then explosive increase in rate of rpms gained all the way to redline. The sensation of bog is not really "bog." That implies that when you open the throttle, net torque decreases. That does not happen. Torque will increase, but increases at low rpm will not be impressive. You think it's bogging because you're expecting 350 lb/ft of torque and 8psi of boost at 2,000 rpm like you get at 5,000 rpm.
|
