Positive diplacement superchargers like on the ZL-1, GT500, ZR-1, my car, etc. don't use a wastegate. This is becouse boost is built after the throttlebody, not before it, like in a centrifigual(sp?) or turbo, Centrifigual(sp?) superchargers do need a waste gate. Boost in these engines is limited by how fast you can spin the blower (pulley sizes) and the engines restriction to flow. Boost and air density go hand and hand. At a given pulley speed and ambient temp the supercharger will displace so much volume of air. Now take that air and cool it and use the same example. Now that the air is denser you have more of it being pushed in for the same pulley revolutions, thereby the pressure built is more (packed in tighter). The opposite is true for heating the air. Now we have come to the reasons of intercoolers and alky injection. We want a consistent air charge tempreture so that we can control things like detonation under boost. My car previous to the alcohol injection would very boost between 7 and 9lbs depending on outside temp and engine heat soak, this is with an intercooler of similiar design to the OE cars above. Now with both the intercooler improvements and Alky injection it stays a pretty stable 9psi, I've seen 9.5 in the winter (makes real good power there
). So yes altitude does effect these cars, becouse it effects air density. But it's not near the effect that altitude has on normally aspirated cars.
BigRat
