Pulsar t28 vs silvia t28

so i have a silvia t28 .64 on the f7r turbo now but i lose all grunt above 6500rpm.
i know a .86 housing will decrease spool but improve flow. however i'm curious how much the .9mm bigger exhaust wheel of the pulsar unit will improve flow?

my thought is to buy a pulsar unit and machine the .64 housing to fit...

any thoughts?

also, how does a gt28rs rear housing compare? as there are many guys running a gt28rs with .64 housing and they don't suffer from bad flow in high rpm's..

i'm trying to find out if it's only the turbo restricting or the f7p cams or both...
silvia dyno's tell me is isn't the flow of the exhaust housing that's restricting...

http://mywebpages.comcast.net/myproj...Dyno_10psi.jpg

cheers,
Arthur

the .64 and .86 refer the rear housing size only fella not the the turbine wheel itself, just found this info on the Nissan turbo's, doesn't look like there's much difference in the turbine wheels, just the housings.

S14 SR20DET: T-28, 60 trim 60 mm BCI-1 compressor in T-04B housing,
62 trim 53.8mm T-25 turbine. .64 A/R turbine housing.

Pulsar GTi-R: T-28, 60 trim 60 mm BCI-1 compressor in standard T-3 housing. 79 trim 53.8mm Inco T-250 turbine wheel .86 A/R turbine housing.

With my T28 I started with a .49 rear housing but it ran out of puff by 5500rpm so I switched to a .64 rear housing, it didn't make anymore power, just moved it up the rev range a little.

A few turbo specs nicked from ATP Turbos, I'm using a GT3071r

GT28rs

Turbine
-Wheel: 53.85mm w/ 76 trim
-Housing: .64 or .86 ar

Compressor
-Wheel: 60mm w/ 62 trim
-Housing: .60 ar

GT2871r

Turbine
-Wheel: 53.85mm w/ 76 trim
-Housing: .86 or .64 ar

Compressor
-Wheel: 71mm w/ 56 trim
-Housing: .60 ar

GT3071r-WG

Turbine
-Wheel: 56.5mm w/ 90 trim
-Housing: 0.86 a/r

Compressor
-Wheel: 71mm w/ 56 trim
-Housing: .50 a/r

GT3071r

Turbine
-Wheel: 60mm w/ 84 trim
-Housing: .63 ar, .82 ar, 1.06 ar

Compressor
-Wheel: 71mm w/ 56 trim
-Housing: .50 ar

according to the garrett site the silvia t28 has a 53mm turbine wheel and the pulsar has a 53,9mm wheel....(inducer)

however i don't think the .9mm is going to make much difference flow wise. i think my best bet is to replace the P cams for R cams.

if i read this correct the gt28rs has the same turbine wheel size? so flow atleast isn't limited by the turbine wheel...


edit: just found out it's the trim that's different:

Quote:

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Looks like your right. I did some research and found that the gtir turbine housing does not fit the s14/s15 wheel. they are both 53.8mm but the gtir wheel is a 79 trim and the s14/s15 is 62 trim.

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I have had a 200sx t28 with the .64 rear and now using a gt2860rs with the .86 rear. The turbine wheel is defo bigger as the .64 wouldn't fit no way near. With the .64 rear and a 60 comp I got full boost by 3k on the b18ft but it did die off and didn't pull as hard in higher gears. With the gt2860rs with 60 comp wheel full boost by 4k and pulls hard to and would go way past the limiter. I did have a smaller comp housing on it 50 I think and got full boost by 3.5k. Full boost is 1.7bar by the way.