exhaust housing for rb25

[czy18e]

G'day,

Been reading a bit into it and i was wondering....

What is the perfect size exh for a 25 i thought a .63 was good but by the looks of the gcg hybrid thing that uses a .8 and is much better with no more lag so lets say you had a 600hp gt 30 with a .63 and a 600hp gt 30 with a .82 both running 18 psi which would perform better as in power verse lag/response.

Cheers.

[Cubes]

?

THe GCG uses the stock RB25 housing that is apparently a .48 or there abouts.

The VG30 exhaust a/r is a .63 and allows better top end VE which = more top end power.

[R31Nismoid]

say you had a 600hp gt 30 with a .63 and a 600hp gt 30 with a .82 both running 18 psi which would perform better as in power verse lag/response.

you cant have a GT30 - 600hp with a .63 rear.

It drops to a 500hp rating then... and possibly 550.

obviosuly anything with a smaller turbine housing is going to do its thing earlier.

But earlier can mean wheelspin at the same time which can mean more nasty to drive.

Boost a bit later can be your friend

[R31Nismoid]

THe GCG uses the stock RB25 housing that is apparently a .48 or there abouts.

but they mill the inside of the housing out correct?

[Cubes]

They machine out the exhaust wheel section to allow for the larger wheel.

This doesn't change the a/r though. Well from what I understand it doesn't.

I've also noted the 500-550hp versions of the GT30 have a different chra. Possibly the 600hp version of the gt30 would have issues with the smaller exhaust a/r?