That sound is from the belt being too tight. Had the same issue on my b18c1 (stock GSR). It gets tighter when the engine is hot. I solved the issue by adjusting everything while the engine is hot... it looks a bit flappy/loose when the engine is cold, but it turns normal when the engine warms up. Best of all, no noise or parasitic drag. I have an aftermarket gates/napa red belt, the thing is STIFF and there is no stretching in it all, so my problem was amplified when the engine was hot.