GTM Performance Engineering: VQ37VHR Twin Supercharger System

Originally Posted by Mike@GTM

Ah, you're referencing the main serpentine belt wrap percentage on the driven side of the stacked pulley. Sorry, I thought you were referencing one of the other pulleys.

First, there is an idler pulley on both sides of the driven side of the stacked pulleys to get as much wrap around them as possible. Also, the driven side of the stacked pulleys aren't as critical in terms of belt wrap as the supercharger pulley itself. The reason for that is the fact that the stacked pulleys are smaller in diameter than the supercharger pulleys. As such, the input torque that the stacked pulley receives from the main serpentine belt is not as large as the output torque at the supercharger pulley. Remember, pulleys are like gears in the sense that a small pulley driving a larger pulley multiplies the torque at the expense of speed (the larger pulley will generate more torque, but turn slower).

A supercharger system with insufficient belt wrap around the supercharger pulley has a tendency to experience belt slip. As you can see in our pictures, we have once again maximized the amount of belt wrap around the supercharger pulley itself.



Interestingly, you guys are talking about the same pulley, just different ends of it. The end you are referencing does have more than 50% belt wrap. If testing reveals that it needs more belt wrap, we've already got a solution worked out. Like I said in response to Nixlimited's concern, however, it's not as critical as the belt wrap around the supercharger pulley itself.