This is for a friend of mine with a 91' GTU. After removing the air pump, what size belt will he need to buy to replace the original one? I ditched the air pump on my FD a while back, but was not sure if the replacement belt was the same size as the one on the FC. (Hope all of that makes sense)

 

If you remove the air pump, it would be difficult to replace it with something else, beings how there's nothing to put it onto.

You friend needs a double alternator pulley, and two new alternator belts. Scrap the old alternator belt (It's probably a bit stretched by now) and use the two alternator belts to make sure your water pump doesn't slip at high rpm.

 

Exactly what I was thinking...

Is your friend aware that by removing his air pump he will lose 5-6th port and VDI functionality?

 

Exactly. Take the airpump off to free up 1 or 2 hp and in the process loose 10-20hp from non-funtional VDI and 6 ports. Congrats, you're making way less power than before. Put the airpump back on.

 

I'll tell him, thanks guys.