Rb25 S1 & S2 Compressors

[salad]

on my rb20 i recently swapped a rooted S1 turbo for an S2.

while both were off the car i noticed that the 2 have slightly different compressors. the upper blades seem to be the same, but the lower blades on the S2 sat further in and were more tucked away out of sight when looking directly down on it. the S1 though had clearly visible lower blades that stuck out past the upper blades a little and seemed to come up higher towards the edge of the upper blade...

sorry for the crappy description

anyway, i ran it past cubes and he suggested it may be the R34 compressor and sent me a couple of pics. the turbo is on the car now so i cant do a proper comparison, but from what i remember its very similar to whats in the pics.

does anyone know for sure if the R34 compressor is the same as the R33 S2?

i always assumed S1 and S2 were the same, just made from a different material. and from what i've seen on here most people think the same thing too

any help would be great

cheers, showza

Edited November 1, 2006 by salad

[discopotato03]

Hard to say if the composite type one was any better than the aluminium ones though I did see a number of damaged late types some years back . At the time I wondered if the composite wheel was a weaker link than the ceramic turbine but without knowing the circumstances in which they died its impossible to tell .

It is worth noting that the R34 RB25 made more grunt than any of the R33's though changes to the engine were made as well . I'd say they removed some of the restrictions in the system and covered any loses with the superior VCT system .

I wouldn't mind seeing the pics of the R34 GTT turbo mainly because I'm interested in the different - larger ?

comp cover .

Cheers A .

[salad]

here are the pics that cubes sent me

pic 1

pic 2

[Bass Junky]

R34 GTT Turbo has nylon compressor. I believe that the R33 Series two has the same compressor, but the R33 sized turbine wheel.

R34 GTT turbine is one size larger.

[discopotato03]

I was under the impression that all the RB ball bearing ceramic turbines were the same , any pics or dimensions ?

Cheers A .

[Bass Junky]

Nope.

R32 turbos are ceramic and ball bearing

R33 Series I turbos are ceramic and ball bearing and bigger than

R33 Series II turbos are ceramic, ball bearing and have nylon compressors

R34 turbos are ceramic, ball bearing, nylon and have a larger turbine housing.

[salad]

so R33 S2 and R34 have the same compressor wheel?

and if thats right, does that mean they pretty much have the same core, only difference being the VG30 turbine housing?

[Bass Junky]

As I understand it, the core is very very similar accross the whole family,

[salad]

if this is the case shouldnt the r33 S2 flow more than the S1? from my understanding the r34 turbo flows more power

but ive never heard of the s2 flowing more power than an s1.

just a bigger exhaust housing cant make that much difference can it?

[Bass Junky]

The R34 Turbo has the bigger housing, hence higher exhaust flow capability.

SII turbo has the SI sized exhaust housing.

[salad]

ah k, so thats it then

so r34/r33 s2 compressor doesnt flow anymore than r33 s1?

[Bass Junky]

I don't think so.

It's the exhaust that is different....

see attached pic.

[salad]

ok, cool

thanks pete!