I've been debating this **** for months now.

I have a beautiful Mazdaspeed Miata with no engine in it sitting out back and I just can't decide whether or not to go with an LS, or a turbo 4 of some kind (k24 or Ecotec).

I'm done with the BP motor, because I've been there and done that and it just isn't a good platform for the power and reliability I want. The bitch is being stripped and welded up to put a stronger drivetrain in, and there's no reason to **** around with a BP when a k24 or 2.2 ecotec would hold all the boost I want, have better transmission options and cheaper upgrades and regular service parts.

The V8 would only be a little more work since I'm fabricating everything anyway. I thought I'd be OK with just buying a C5 z06 and calling it a day, but I miss my Miata and having a boat of a chevy just isn't what it cracked up to be.

So what's your opinion? Go with beautiful turbo noises and a **** ton of HP with not as much low end torque or a fat *** tractor motor and truck noises?

 

Briggs and Stratton swap

 

Woah man, I'm not trying to build a rocket ship here.

 

whats the budget?

 

It's pretty open as far as budget goes.

Since all the Fab work will be done by me, I'm probably looking to spend around $10k in parts and probably a couple hundred hours of labor on my part.

I'm definitely going to cheat on the tubular subframe and the diff mount, but everything else will be fabbed.

 

I vote k24 frank with a c38-91 rotrex.

Edit:
What are your power goals?
What is the cars purpose?

 

volvo inline 5

 

CUMMINS 2.8 Turbo Diesel

 

solid state fuel, single nozzle optimized for power not rate of burn.

 

K24 because easy and cheap conversion, and parts for turbo are available.

I don't want a non-turbo Miata.

 

I wish I went k series, I bought my bp6d like 2 weeks before the released the new k swap kit

 

You say you're done with BPs. Can I interest you in a B6. It's even more old school tech that just works.

 

It's never too late to change your mind

 

I vote V8. Great sound, torque, wow factor, the Miata is a great fit for it... plus how many V8 Miatas can you count vs. turbo-whatever. Mine is the only one I've seen in person. I bought my subframe used (amazingly) but others have fabbed it using the oem subframe, which may actually be stronger. This thread on V8Miata has details https://www.v8miata.net/general-moto...d-thread-2893/

Rear diff mount isn't too bad, that's what I did. Most of the money will probably be in the engine and T56 if you go that direction. Leaving well enough alone will also save you money. But "small car, big engine" likes to have brakes, and tires, and well, you get the idea.

Good luck with the decision.

 

I do like linear power, but I'd still rather go turbo k24 if I do go that route.

Power goals are around 300-350ish wheel and extremely beefy reliable drivetrain.

It's going to be a daily driver with too much power and good AC

 

350 is super easy on a K24. Even the "bad" K24s.

 

Well HP isn't my main goal here. I just want it to be easy to whomp from light to light while retaining the Miata-ness.

I'm not sure if a k24 would have the low end torque I want.

 

It will

 

If reliability is most important, a V8 drivetrain pushing a 2500lb car is going to be more reliable than a turboing a 4 cylinder.

 

I can't tell if I'm down a cylinder in my V8. If that's a good or a bad thing, I don't know.

I'm only running 205 rubber, and learning throttle control is huge. The car goes from being an exercise in inertia management to "on off on" throttle reaction. I still need more seat time to be smooth - but it doesn't quite drive like a miata anymore. And no, it's not weight - it's torque.

And I'll bring this up - I've been turbo'd at 260, we have the LFX that is 325hp at the crank, and my LS3 which is 425hp at the crank. The LFX still retains stock-like driveability with predictable power - on 205's you can wring it without expecting the rear to step out unless commanded. I'm still scaring myself with the LS3. I expect I'll get better. I will state that the getrag is superior to the torsen - you can feel it work.