Originally Posted by Alizarin

warning...

Not quite. They're not forced to spin backwards, it has to do with pressure waves coming back off the closed throttle plate and striking the compressor blades. Some of that pressurized air also passed back through the compressor and out the inlet of the turbo. This combination is what causes the dreaded "surge" noise. Sure, the compressor wheel slows down, but it won't reverse.

Or, think about it another way. You have the shaft with the turbine and compressor wheels spinning at almost 1667 revolutions per second (assuming 100k rpm which isn't a bad assumption at full bore, some turbos spin over 200k rpm). That's a whole mess of inertia to overcome to make it spin backwards in a fraction of a second. Which means a very large force is needed. I have a feeling if you do the math, you'll likely snap the shaft or totally destroy the blades before that happens. Not only that, but you still have exhaust passing through the turbine wheel, causing "forward" motion.


Also, ryan, you provide no links. The lazy among us won't search for it if you're going to shill it.