difference between .62 and .82 exhaust housing

[that national]

this may sound stupid, but what are they talking about when they say .62 and .82 exhaust housing?

 

[Tin Man]

Those are exhaust housings for the turbo. The smaller housing generally lets you use less stall and has faster spool up. The bigger housing gives you better top end.

 

[suicide six]

smaller number is generally for street where as .82 is for mainly track use.