are you changing pistons?

actually the redtop and silver top bottom ends ARE THE SAME as GZE bottom ends, except for pistons.

 

with a good safe tune and aftermarket ecu which you will need, you should be able to run up to about 9-10ish PSI

 

or with the GZE pistons, 20+ psi is a snack.

 

as everyone else has said, the ball bearing T28's off jap S14's and all S15's are a very good turbo to use, or one T25? off a GTR if you want down low response. don't go over 14ish PSI with a GTR turbo unless you get it rebuilt and ditch the ceramic turbine wheel.

 

so since your going bigport, do you wanna sell your smallport head?

if one was going to all the hassle of changing to bigport for more flow you would also want to go maximum boost, so you would definately go aftermarket computer and t28bb.

 

nice to know the standard pistons will take 10psi...i saw a set of ARIAS 4age forged pistons (8.?: 1) on ebay for $699 brand new

Personally I think unless you're willing to crank a T28BB up into its efficiency range (i.e. 12-20psi) you're better off with something smaller (and cheaper).

 

 

as everyone else has said, the ball bearing T28's off jap S14's and all S15's are a very good turbo to use, or one T25? off a GTR if you want down low response. don't go over 14ish PSI with a GTR turbo unless you get it rebuilt and ditch the ceramic turbine wheel.

 

They call GTR turbos T28s but they're far smaller than any T28 you'll find on an SR20. They're even smaller than T25s on CA18DETs. I think you'll find it will run out of puff up top.

hence the low down response comment.

 

ive heard of a few on 4age's, seen the dyno sheets and they definately do the job, but like you said they definately start running out of puff in the mid-high rev's. a good street turbo. personally id be going for an S15 myself.

 

or if you after BIG BIG power (and associated lag) disco potato's with the small (i think .48 from memory) turbine housing is the go.

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Edited May 24, 200818 yr by Sbox

Its hard to tell without measurements but it looks more like a T3 flange to me. Post up some measurements and I'll see if I can tell you what it is. If it is a T3 flange try an RB20DET turbo. They're about as easy to find and as cheap as a CA18 T25.

 

If worse comes to worse and I can't get another turo, I will have to give me truck one a go.

 

Don't...it wont work.

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Edited May 24, 200818 yr by Sbox

if it is a T3 flange, saab turbo's off 900's and early 9000's would also be a good choice. ya can pick them up cheap as chips and would go quite well on a 4age

...and there is one off a saab turbo on ebay right now for $75

That exhaust housing looks like it came off a bloody truck....good luck spooling that thing

 

Yeah i read that bit but it doesn't say that it is a truck turbo it sez it looks like one, This whole thread is jumbled.

:D exhaust a/r 1.15, this is suitable for a 5.0 litre V8, at minimum, and as the ad says approx 500rear wheel horsepower. The compressor housing on the other hand is more suitable for a four cylinder, so basically this is a poorly created turbo, :)

 

Oh well, probably should do some research next time.

Edited January 1, 200719 yr by oh what a nissan feeling!

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Edited May 24, 200818 yr by Sbox

Don't panic whatever the manifold measurements end up being. You should be able to find a turbo for it regardless. The only reason I'm suggesting Nissan turbos (or should I say turbos off Nissans..they're mostly garretts) is that they're the most plentiful turbo you will find. I can't imagine a replacement Saab turbo is easy to find.

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Edited May 24, 200818 yr by Sbox