S15 Turbo Discussion

[Busky2k]

Nah the Trust T518z made 1.2bar at 3000rpm, the funniest thing about it was that I couldnt even do that with my stock turbo on my old S14. But despite this, the stock turbo is still more responsive below 3500rpm due to the lower inertia of the comp/turbine wheels. ie builds boost faster when u flex ur foot.

The whole BB vs nonBB on the S15 is a completely messy issue, with everyone claming a different thing. Basically most late model S14as and S15s came with BB cores but some claim from their findings they didnt. The JDM ones are BB as far as I know. To tell if the T28 is BB or not, just take a look at the turbine housing and it'll have a separator lip between the wategate and turbine outlets.

But why bother with a stocker, its basically a GT25R. If you had to try a Garrett turbo off the shelf, I'd try the GT28RS which as the higher flowing comp/turbine wheels. Same diameter tho! I reckon they'd work pretty damn well on an RB20. I think discopotato can chime in a bit here and fill you in some more.

Edited April 25, 2006 by Busky2k

[discopotato03]

I don't think Garrett make a T3 flanged GT28 turbine housing so theirs don't bolt up .

Your probably limited to a Hi Flow or one of the GT28BB's in a reprofiled RB20 or RB25 housing . The HKS T3 flanged GT2530 or GT-SS stand the best chance of giving good results because they're designed to suit the application . Cost aside GT-SS sounds best to me for road .

SR20's are much better looked after because they were designed around T25/GT28 turbos with the common T25/28 flange .

Cheers A .

[TTT]

man this thing went off topic..

glad someone bought it back a little.

I just wanted to know if there was anything stoping the RB20 making the same sort of power using the S15 turbo.

As in ... is the S15 turbo (the turbo itself) capable of producing the same numbers on the RB20 os is there something about the RB20 that stops it doing so.?

no more SR v RB bullshit.

Also, the whole ball bearing and non ball bearing thing has been sorted long before..

it is not about which car it came in or which country.

The only thing that the splitter on the exhaust side says is that it is from an S15, but doesn't always mean ball bearing.

only the part numbers sort it out.

All that matters is the garret number, everything else just confuses matters

466541 = ball bearing

466543 = bush bearing

for the second bit of the number

-001 = S14 turbo (no splitter between wastegate and turbine exit)

-002 = S15 turbo (splitter between wastegate and turbine exit)

cheers

[Cubes]

As Roy pointed out.

The RB20's with RB25 turbo's strapped on make very very similiar numbers to the rb25.

I see no reason why the will SR make more power other than a dyno reading differently or the rb having a slight problem causing power to be a little low.

Come to think of it there's an SR20 S13 on the dyno I run on and it made around 180rwkw (will confirm exact power tonight) or so with an S15 turbo bolted on the side running a stock ecu.

Its very common for an RB20 to make 190rwkw on 14psi with an rb25 turbo.

I forget exactly what Nightcrawlers S15 made..

[Busky2k]

Nightcrawler made high 190s with the stock turbo. Theres still more to go though, as I've seen upto 210 is the norm. Cammed of course.