EFR 6258 vs 6758
 

So right now I have the 6258 at 17psi making 311/285. I am very happy with the numbers, but I am reading more and more that the 6758 can make more power, and the loss of spool is marginal. Who's made the upgrade and what have you noticed? What kind of power can the 6758 make on similar boost?

IIRC the outside dimensions are identical so it would just be a straight bolt-on swap.

You need a 7163.

Do it.

For great justice.

I don't want to re-do my manifold and exhaust. I also don't see a need for the kind of power it can produce in such a small car. That's why the 6758 is kind of an idea. Not something I'm guaranteed to do, but if I knew I could sell my 6258 (3000mi) and get a 6758 with marginal difference in cost, I would consider it.

I think soviet is the only one.

Funny how Russians think alike hah

I just went straight for the 6758 after soviets experience.

I went for the S366.

Are you stuck on 17psi for some reason? The 6258 should be able to make more power as you increase boost, if more power is what you are after. It would likely be less expensive than buying a 67 and taking a loss on the 62.

The 7163 is on the same frame as the 6258 and 6758. I believe it is a direct swap turbo. You would want to verify that but I am 95% sure that is the case.

How much more boost can I run with 93 octane and ~8.6-8.8 compression?

All of it.

Pretty sure FM proved that the GT2560r is just as good so why don't you just get one of those?

(I can't tell if I laid the sarcasm on thick enough so I wrote this footer)

Which one does the Trackspeed Engineering kit use? I would use their R&D and follow suit (since we laying on sarcasm).

Funny thing is that listening to people on this site, looking at Soviet's thread, and the mythical TSE turbo kit, I just decided to put together my own package. I love driving this car, it feels incredible. So really, how much boost? My timing according to tuner is still pretty conservative.

How much boost? All of it.
How much timing? All of it.

But seriously, I'm only half joking here. If you're at 17psi, that turbo should handle well into the mid 20's, and if your timing is conservative, you should be able to bump that up another 5* or more depending on load.

The issue then becomes with fueling: you can only go so far on pump gas. Then you need water/meth/etc or run e85 or race gas.

Then you will start running into much more important problems, like replacing grenaded transmission, diff, axles, etc.

I already have an MSM diff with the bigger axles, and it's a puddymod stage 2 cryo treated and with 3.63 mated to an MSM 6-speed via a super miata driveshaft, and fm lvl2 clutch, if that matters.

I get 93 octane, will talk to tuner and see what he thinks.

At over 400whp, all that stuff will be pretty much at or past the limit.

Also something to consider is uncorking more power with more flow. Like a squaretop or honda mani, tb, and maybe even cams.

That's what I'm doing lol. Just picked it up today

I was considering the squaretop or the Honda d or h series manifold. I have 2" intercooler piping but that's plenty large, it's the same size as the cold side exhale port (I forget the name) on the turbo

Weight reduction is another idea. Might want to ditch ac. Anyone know what the compressor and condenser are worth in lbs?

2" ic piping, if I'm not mistaken, should max out near 400hp at full tilt assuming no sudden bends or anything