Apologies for resurecting an old thread, but most of the info I am after is mentioned here.

I have an opportunity to upgrade the HKS T2 turbo that came with my kit (compressor 0.48 A/R, turbine 0.49 A/R) to an SR20 T25 turbo with an A/R of 0.80 (compressor) and 0.64 (turbine).

I have measured the inlet flange of the turbo and it will fit on the manifold, the downpipe will need to be redone (4 bolt housing going to a 5 bolt housing).

Would the larger T25 be significantly different in terms of spool?
I don't mean by margins of 500rpm (currently on MS logs of 4th gear pulls, i get 6psi by 3000rpm), would the T25 be similarin this respect?

I seem to recall that some SR20 turbos are not as suitable for the miata engine, but where exactly i read that escapes me now.

Cheers
Nuno

I was going to run the Sr20 turbo, makes for better top end, and like braineack said, its like a journal bearing equivalent of the GT2554...or close enough, same manifold/dp will work as with a GT25 series

at the moment (7psi spring on the internally gated turbo) the spool is great, even though I have a right angle (read square) down pipe, but i feel as if up top it does flatten out some (I will have a dyno run in a couple of weeks). so the SR20 one should breathe a bit better given its higher turbine ar numbers right?

at the moment (7psi spring on the internally gated turbo) the spool is great, even though I have a right angle (read square) down pipe, but i feel as if up top it does flatten out some (I will have a dyno run in a couple of weeks). so the SR20 one should breathe a bit better given its higher turbine ar numbers right?