they didnt come from a sr20... its possible that those are from an RB or anouther nissan tho

Seems like you got a T28, it looks the same as the one I used to have anyway:

http://farm1.static.flickr.com/63/22...0c1aca2811.jpg

More pics here:
http://www.flickr.com/photos/saboteur/tags/turbo/

So what the kinda T25 do I have sitting on my desk. .80A/R on the compressor and .64 A/R on the exhaust. Its like nothing mentioned in this thread.

How did you deduce that? Is it from the round compressor inlet (just so I know what to look for next time)?

How about FWD SR20 T25? Do they look the same as RWD T25s?

www.nicoclub.com .... GREAT nissan forums. there is alot of info spread throughout there about the differences including pictures and discriptions

It's probably what I know as a t25g, when you look at it side on the comp housing is wider. Im pretty sure thats what is on the s13.

Yep, you are right its a T25G. Thanks for the insight.

Its like a GT2554 by those specs. Good to know.

Sam i've got the same turbo. What type of power are you expecting?

My initial goals will be 180 - 200. I dont plan on going further and I think this turbo will give me just that easily.

The only way you'll be able to see a difference is the compressor wheel:



since the compressor in the t25 is smaller, you can see the large "lip" http://boostedmiata.com/lars_t25/larst25008.jpg(1/2") on the housing. a t28 will have a very small lip if any.

otherwise they look identical, aside from part numbers.

There seems to be some confusion regarding the garrett turbos that came factory on Nissan cars here. This is the info I have gathered from being in the SR20 scene for 9 years now. I've owned/driven a turbo B13 SE-R for 7 years so I know a little bit about the stuff. :)

FWD:

journal bearing t25 (most) Good for 250whp (2.0L) .64 exhaust housing
ball bearing t25 (later ones, rare) Good for 250whp (2.0L) .64 exhaust housing.

The fwd t25s have the same specs as the rwd turbos however there are a couple of differences. The compressor inlet is not a 2 bolt flange, it uses a coupler connection. The compressor outlet is the same 3 bolt pattern but clocked differently. They turbo on a fwd car is flipped around compared to the rwd but it can be easily re-clocked.

journal bearing t28 (GTi-R, sort of rare) .86 turbine housing. T3 compressor housing with 60mm wheel. Good for 300whp+ (on a 2.0L) A good upgrade is to swap on a T04b housing from the rwd t28 (you need the backing plate too).

RWD:

S13 t25s (all journal bearing afaik) good for 250whp. .64 exhaust housing.

S14 t28s. (All ball bearing) Have the same .64 turbine housing as t25s. They have a t04b compressor housing with the same 60mm T3 wheel as the GTi-R t28. Some may have the cast in divider on the turbine housing. Good for 280whp+ (2.0L)

S15 t28s (All ball bearing) Have the same .64 turbine housing as t25s. They have a t04b compressor housing with the same 60mm T3 wheel as the GTi-R t28. They also have an inconel turbine. This turbo is sold in the aftermarket as the GT28R. All have the cast in divider on the turbine housing. Good for 280whp+ (2.0L)

There are other t2x variants from Skylines and 300ZXs but I'm not familiar enough with the specs to comment on them.

Very good little write up there, that is quite accurate. The only thing missing is spool characteristics, boost threshold and the compressor maps (which are hard to come by).

The OP's goals are 180-200 and a T25 would easily give that and be better able to hold the power curve a bit higher than the typical SR do to the 1.6-1.8L displacement of the miatas. The t25's are cheaper and MUCH more plentiful; the also don't have any widespread issues or problems with them and should last quite a while if run < 1 Bar.