so how does a turbo work in reverse?

[DBourne]

there's nothing i can ad to make this funnier, but just read it.. it managed to brighten my friday morning!

http://www.cobaltss.net/forums/showthread.php?t=118899

[few snipets]

So we all know that the supercharged engines need the intake bypass valve so they work in reverse. Otherwise the supercharger would just suck all the air out of the cylinder. So knowing that, how does the turbocharged version work in reverse? The engine is trying to suck air backwards, yet the turbo wants to spin forward so I don't see how it works. Is there some sort of exhausting intake bypass valve on the turbo version? Also, if it does have the valve, does that also mean that it can make boost in reverse? Like how much boost? Like 5 psi or does it go over 20?

then later on after the sh*tbagging he gets:

wow, lots of replies already, thanks guys

Real reason I'm asking because a friend is getting a 93 Corvette and he wants to race me. I said we can race to 30 mph because I think if I go from reverse I'll get better weight transfer and beat him, but I'm concerned about making full boost since the turbocharger will be spinning backwards.