Which turbo would best work for what I want to gain?
 

I recently acquired a 1999 10AE Miata with a built engine that is already tuned. It already has upgraded injectors, a Microtech LT-10s EMS, FM exhaust manifold/downpipe/full exhaust, and a crappy T25/T28 chinacharger that was rebuilt when the engine was built up.

I am looking to replace the current crappy Chinacharger with a better turbo that can help me better match what I want.

My goal is 280whp, and would like the turbo to spool up as early as possible.

For the most part, I am currently torn between the GT2860R, GT2860RS with the .64 A/R housing, and the GT2860RS with the .86 A/R housing.

Which of these would best suit my goals?

If you're not looking for much more than 280, the 28rs with .64 should get the job done and provide a very enjoyable curve.

Honest question: why isn't the 2560R listed?

Only reason I didn't list the 2560 is I understand that 280whp is at the very edge of what it is capable of.

If I could reasonably get 280whp out of it, I obviously wouldn't object to it either.

Better stated, I guess would be a range... I want to have between 270whp and 295whp, which I am guessing (from what I have read/looked at) would take somewhere around 14-18psi which would be better suited to one of the GT28's...

Won't a 2560 be closed to maxed out at 280 wheel? I know Paul made 300 with one, but thats really not that common.

*edit; OP beat me to it:)

If you might want more later why not go with a 2871 then? Easily capable of 280 and even 350 without sacrificing much lowend, if any.

I think sav has dyno charts showing the difference between the 2860 and the 71,

Negative, he wants the .86.

.

So, from what I am seeing here is that I have to really decide what is more important to me... Meeting my whp goals, or spool up minimization goal...

*sigh*

http://cgi.ebay.com/ebaymotors/Genui...item230e516c80

Less than 700 bucks and will get you to 280whp easy *With the proper supporting accessories*

Spool characteristics can be found all over this forum. It is a VERY popular turbo.

Seriously. 2560. There's no reason to go with anything else.

Reading the spool data thread, made me remember to mention that I am at almost 5000ft elevation as well... If that makes any difference.

Awesome. Put on a good 2560R setup, then go to FlyinMiata and they'll dyno you in at 330whp.

Ah... So the plot thickens... In reading thread after thread after thread...

I came across the BW EFR turbos... Any thoughts towards going with the BW EFR 6255 or 6258?

I think that either would meet both of my goals...

The 6255 is useless for Miatas. No better response than the 58. The 6258 is a 450whp turbo, which would meet your 280whp goal.

A massively oversized turbo for your goal is not the best way to get maximum response.

Damn.

Really kinda seeming like the whp I want is in a limbo area, at the top edge of a 2560, and at the bottom edge of the GT2871R, GT30R's and the 6258... And it seems not many around here like the 2860RS... It will be a couple weeks-couple months before I can get it anyhow, waiting on my tax refund.

Well, Nagase, seeing that you are in Phoenix, any chance you might know of any good tuners down Tucson way, or any tuners at all that are good with a Microtech LT-10s? I've got nothing down here in Sierra Vista.

I have a GT2560R that I'm shooting for 320whp on.

With a good setup, 280whp shouldn't be anything, depending on if the dyno is a killer or not.

And no, never looked into tuners. I have megasquirt, I do my own.

I wish someone would just start actually producing airfoil bearing turbos...

Would make my decision ridiculously easy then...

Great. I think I will probably actually go with the 2560R then... If I feel I need more, I can always sell it later and get something bigger.

What is the real sweet spot for boost on the 2560R?

Not sure what you mean by sweet spot, but I'm going for ~18.5 psi.