350whp NB
 

First I wanted an ND but it sounds like those engines and transmissions are ticking time bombs at that HP level. I don’t like the look of NC so that leaves the beautiful NB. Sounds like I should go for a later model 1.8 VVT version.

What’s the best reliable pump gas way to get 350hp w/ turbo out of one of these bad boys? I don’t mind spending money to get parts, and I don’t mind turning wrenches (even rebuilding with forged internals), but I don’t have the shop or the skill to build custom parts myself.

I’m finding it hard to find places that sell all the high end parts for these cars anymore, and even more difficult to try and put together a cut sheet of what I’d need. What’s the dream build for something like this?

Don't think you're gonna make 350whp on pump gas without meth on a stock motor

this is pretty accurate, I did a full build with a 6758 and was det limited on 93 to 305whp on a roller dyno (virtual dyno put me at 340whp but I really think thats generous)

but this forum is a wealth of information with the search bar -- full builds are everywhere nowadays and documented well.

Fair enough. I was afraid I’d have to graduate to an engine-swap. Sounds like that also means transmission and rear end as well.

I’ll keep searching the forums. The hardest thing I’ve found so far is to find builds that utilize parts that are still being sold. A lot of stuff is no longer in production.

Carpassionchannel on YouTube is a great resource for how to make big power with a turbo BP motor. At 350whp you're close to the point where a turbo K swap should be considered. Either way you're looking at a drivetrain swap to handle the power.

350whp on stock internals with pump gas is a "dangerous" place to live. You'll probably bend a rod (or two) before you get to that level. If you're going with forged internals (and maybe a 0.5mm , or 1mm overbore) and a decent turbo, and are prepared to source some 97 octane gas, then you can probably get to 350whp...or beyond, short term, for bragging rights. You'll definitely want a 1.8L block and a VVT head wouldn't hurt. And your TunerStudio-fu had better be top-notch.

Build it strong. Build it smart, and know when to quit. A 200whp Miata is a hoot. A 300whp Miata is a kick in the ass. A 400whp Miata is more than most of us can (and in some cases, should) handle. Beyond that level, you're talking about bleeding edge boost levels, 100% corn-juice and Bill Gates budgets (with the potential for frequent heartaches).

Like Dr.Sep, Virual Dyno says that I'm pushing 340-ish whp on my 6758-based build, but I limit myself to 200kpa and don't (often) go beyond 6800RPM on the street. If I went to a dyno I think my "true" HP level is closer to 270-280 than the 340 that VD says - and that's good enough for me. I'd rather enjoy my car than to rebuild it (again).

Super helpful info - thanks a ton. I’ll keep everyone updated if I start a build with my plans!