Supercharged Corvette

C7 Z06 COTA 2:17s PDR Laps
Adam Tobolowsky
I am a little bit impressed that big stodgy old GM produced this (or will. It might not be until next year.).  I hate to admit it but it was a spam comment that turned me on to this, and this:

The 2015 Corvette Z06 features an all-new LT4 engine. The supercharged, 6.2L V-8 will deliver more than 625 horsepower, and 635 lb-ft of torque.

600 horsepower!?! That's insane! I wonder how long the transmissions will last. They must be making them out of titanium.

    You will notice that there are two serpentine belts on this engine. One goes around the front of the crankshaft pulley, over to the left side of the engine (right side of the picture) , around two idler pulleys, back to the center, around two more idler pulleys and then up to a single small pulley by the throttle body (the brass colored round opening in the center) that drives the supercharger. Note the difference in size of the crankshaft pulley and the supercharger pulley. The engine redlines at 6,500 RPM. The supercharger turns at 20,000 RPM, much faster than any I have encountered before.

    The other serpentine belt goes off to the right side of the engine (left side of the picture) and drives all your conventional accessories (from top to bottom: alternator, power steering pump (I presume) and the A/C compressor).

P.S. The only reason I can think of that would explain why they used four idler pulleys on the drive belt for the supercharger instead of just one is that they must of had some kind of resonant vibration problem. The other belt that drives the accessories is traveling just as fast, being as it is driven by the same diameter pulley on the crank, and it spans longer gaps between pulleys, so maybe that isn't the problem. I'm baffled.
    Then there's the question of why they didn't use just one belt instead of two, but that could be explained by (1) the power requirements of the supercharger (it needs one belt all to itself), or (2) most engines are built without a supercharger, and this makes it a bolt-on installation instead of a built-in one. Never mind that the internals of the supercharged engine are almost certainly different than the standard engine.

Update October 2016 replaced missing video (Chevrolet Corvette PDR (Performance Data Recorder) playback.) with something similar.

Update February 2021 replaced missing video with something similar.