Gt4094R A/R 1.75!! for a roadrace 600hp 20B?
 

What do you guys thing of this? I Am willing to loose some spool and low end to gain some reliability (read heat manegment) and let the engine breathe properly. Got a killer deal on this turbo from my local shop and they say it will be perfect for a ported roadracing 20b.

The turbine housing is a bmw f1 housing and they are very cheap and bolt on.

Can't tell without pictures ;)

1.75a/r is massive.

yes its massive.....but it is to massive.....that is the question :-S

Yes, its unnecessarily massive lol

On my 20b, it runs a BWs480 modified to a smaller T4 housing and only a 1.15AR, as I only want the powerband between 4.5k-8k. And it even wants to pull past the rev limiter. Full boost by round 4800rpm and 600hp @ only 13psi, it sees positive pressure by nearly 3000rpm (2-3psi)

I've seen cars with the full size BWs480 ( 1.32AR T6 housing WAYYY massive) and the transient spool looks considerably slower than my turbo. I'm not sure how exactly these specifics compare to your idea, but in my opinion, I'd would assume that the turbo you're considering would be miserably laggy

You mught be right, allthou both my turbinewheel and compressor wheel is alot smaller then yours, i also tjenk the shaft is smaller and lighter plus it is a BB turbo so it should not be to bad....there are 1.19 housings aswell so it might be one of both so i can try em out. I wish for full boost from max 3000rpm to min 8000rpm :-)

Good luck!!!! Let us know how it turns out.

Don't we all :lol:

When I was running the GT4094R (106a/r)on my large street ported REW,in 3rd gear I would not usually get to 10psi till 4750rpm.Over a 5 year period, I tried everything to get it to spool better including changing the manifold, adjusting the spool-up tune with AF ratio and ignition adjustments. The absolute best I got was on a very cool night was 10psi @ 4600 in 3rd while running maximum boost @ 28psi. The only thing I did not do was change was the turbine housing to the smaller .95a/R. I eventually switched to a BW 366 my car is much more street friendly hitting 10 psi at 4100rpm in 3rd and 3600rpm in 4th. Other folks like HC have had better luck with the 4094R.