Why not MZR NC Miata engine into an NA?

I know I've seen a few bits here and there about why it's not worth the hassle, but why specifically?

This would be for a nice weather driver/track toy, no emissions tests to pass or vehicle inspections to comply with.

I know they are ~170 stock, what does the typical intake/full exhaust/tune net out of them? I figured that would be the perfect amount of HP for my '90, and wouldn't require a built 1.8 to get there.

Keith, I know you'll chime in with just turbo a healthy NA motor , but I'd really like to avoid FI with the heat we have during the summer, and I really don't think I want the 350-400hp of a V8 swap in the car.

Thoughts?

The NC shares nothing with the NA/NB. This means that swapping an NC motor into an NA is roughly the same level of difficulty as swapping pretty much any other longitudinal mount engine there (lots of custom fabrication required). So, sure, you could swap that motor in, but it's a ton of work for 170 hp and if you're going to do all of that why not get a 240hp Honda S2000 engine instead?

What type of fabrication? New oil pan? New crossmember?

I want specifics. I've got a good buddy who can handle anything like that.

Get the dimensions for the engine and ask your good buddy. Likely will also need the new trans, full engine rewire, driveshaft, the 1.6 rear won't do well with that power, so you need a new rear end. need to integrate the new ECU, or go aftermarket... Now, if you find a cheap rolled NC, might be worth your time.

http://forum.miata.net/vb/showthread.php?t=341403&page=35&highlight=finiata

The folks over the the NA Power section of Miata.net say that an internally-stock 2001-2005 engine, with intake, header, exhaust, and aftermarket ECU (with VVT control) will get you to 150. As mistanfo points out, your rear end will be the weak link, but this will be much, much easier than a MZR swap. Close enough for you?

Any future plan includes going to a later-Torsen diff. With the stock 1.6, good suspension and R888s, an open diff doesn't affect anything.

Checking out earlier link now.

peter wrote: The folks over the the NA Power section of Miata.net say that an internally-stock 2001-2005 engine, with intake, header, exhaust, and aftermarket ECU (with VVT control) will get you to 150. As mistanfo points out, your rear end will be the weak link, but this will be much, much easier than a MZR swap. Close enough for you?

Really? Assuming 15% loss, that means an intake/header/exhaust/tune is worth about 10hp.........that's pretty tragic.

Also, no need for A/C or PS.....

The biggest issue would be plumbing. Not that a good fabricator can't get around it, but the inake/exhaust sides swap on the newer motor.

BTW, if you are going to do it, I would also suggest trying to find a 2.3- the block is a little taller to get the displacement, but if the effort is going to be gone through- might as well get the extra grunt. AFAIK, all of the Miata stuff will drop right onto a Ranger lower block- it's all the same thing. Could be wrong, but I have messed around with the engine family.

I've thought about it, too- especially since the newer motor is considerably lighter, being an aluminum block and all.

(side note- a MS should work fine with this family- there's nothing really special, technically, with the family.)

z31maniac wrote: Really? Assuming 15% loss, that means an intake/header/exhaust/tune is worth about 10hp.........that's pretty tragic. Also, no need for A/C or PS.....

Sorry, I was unclear. 150 at the wheels. Stock was 140 territory at the crank. So yeah, not a massive jump if you have an NB, but my 94 supposedly makes 100 at the wheels on my stock mill. I'm bored, so it's worth my time :)

The stock NC motor is rated for 168 at the crank.

z31maniac wrote: What type of fabrication? New oil pan? New crossmember? I want specifics. I've got a good buddy who can handle anything like that.

I don't have any specifics, nor have I seen any writeups on what's required. But, since the cars are no more compatible than any other front-end, rear-drive, 4-cylinder cars, you'll have to solve all of the attachment problems. Maybe they're easy, maybe not.

Does the oil pan clear the subframe?

Does the shifter line up?

How do the motor mounts works?

Does either the NC or NA PPF bolt up? (It might, but I doubt it). Do you want to modify it? Weld the front of an NC PPF up with the back of an NB one? Or go with conventional transmission & diff mounts? If so, you'll be fabricating those.

Does the NC transmission fit in the NA tranny tunnel, or does it require a BFH? A torch/welder?

The NC has intake/exhaust on opposite sides vs the NA/NB. Is there enough clearance on the intake (previously exhaust) side for the NA's steering shaft?

How much of the exhaust is custom? Does the NC header fit?

Then there's the comparatively easy stuff -- computer, wiring harness modifications, PS/AC lines (could leave those out, I suppose), coolant & fuel plumbing, etc.

Take a look at the writeups on the FM site about how they do LS3 V8 conversions. An NC-into-NA transplant requires solving all of the same problems, although it is probably not quite as hard since the NC 4-cylinder isn't as big as an LS3.

I don't want to be a downer, but there's a LOT involved. If I were doing that much work, I'd want more than a 20hp boost (vs a fairly-easy NB VVT swap) as my reward.

It definitely does!!! Perhaps ill reconsider a late-model NB engine.

codrus pretty much nailed it. The cars aren't related at all, so an MZR is no easier than any other similar engine. It's a pretty decent one - most people know it as a Duratec - but it's not really the most characterful sports car engine out there in stock form. If you're going to go to all that trouble, you might as well get some real benefit out it your work. I agree the (tall) S2000 engine would be pretty fun, although every Miata owner who calls us is looking for torque, very rarely are they looking for another 1500 rpm over the redline.

BTW, I seem to recall the PPF on the NC is a Z cross section as opposed to the C used in the earlier generations.

TQ is good, but I wouldn't mind a high-rpm screamer for a track car.

Thanks for the info gents, guess I'll need to read around some about aquiring an NB VVT engine. 60ish HP over what I have now with the stock 1.6 would be amazing.

Cliffs Notes

Same thing

More of the same

The song remains the same

There ya go :)

^Yeah, I spent last night and this morning reading up on the 1.8 VVT engines.

Seems like that would perfectly suit the power goals I'm after, and for about the cost of proper turbo/cooling setup, I could build a strong, reliable 1.8 and have 160-170whp.

Which would be huge compared to the 90whp now.

As with anything, take all claims with a grain of salt.

I have yet to see a dyno that shows the EUDM/JDM "square top" intake manifold offers any gains in the low/mid-range, though that has been claimed, IIRC. The only back-to-back dyno I've seen is on FM's 2L stroker (Yolk?), and showed gain only in the high RPM range. Not sure how this translates on a normal motor.

I have seen no evidence that the fancy new throttle body everyone wants to sell makes any power, but supposedly evidence is forthcoming.

Other than that, seems pretty straightforward.

If you look inside the square top, you can see why it's going to give up midrange for top end. Massive runners by comparison to the US version. So the dyno results we found were not surprising. I believe Bill Schenker has gone away from the square top for the same reason on his CSP car.

z31, watch out. There's a ceiling to affordable naturally aspirated power of about 140-150 rwhp. There's lots of talk but a notable lack of dyno runs. Very few have made it into the 160-170 range. Ignore anything posted by "POPSTOY" on Miata.net, there's a real lack of testing backing up his assertions and our dyno has proven quite a few of them wrong.

Keith, any "build" would likely include cams, slight headwork, +1mm pistons with upped compression, aftermarket rods, and a standalone ECU for a proper 91 octane tune and the requisite intake/header/exhaust.

Does the 160-170whp number sound reasonable with the above information?

I figured that's approaching a $10k motor, but also figure an FM turbo, with the proper cooling setup for the radiator and oil cooler is basically $8k, plus a basic refresh on the current engine.

The turbo would make more power, no doubt, but I think I'd really rather avoid that route. And I think a V8 Miata is just more power than I really want.

Keith Tanner wrote: Ignore anything posted by "POPSTOY" on Miata.net, there's a real lack of testing backing up his assertions and our dyno has proven quite a few of them wrong.

QFT. Listen only to how much money this guy has spent. It's a E36 M3load. Don't do that.

z31maniac wrote: Keith, any "build" would likely include cams, slight headwork, +1mm pistons with upped compression, aftermarket rods, and a standalone ECU for a proper 91 octane tune and the requisite intake/header/exhaust. Does the 160-170whp number sound reasonable with the above information? I figured that's approaching a $10k motor...

Wait wait wait. Let's be conservative and say a stock NB mill with the mods mentioned will net 140hp. Let's say you spent heartily on a junkyard NB mill, the I/H/E, ECU, and the tune. I'd call the motor $1000 (high end), I/H/E $1000 (high end), ecu/tune $1000. (I'm in a rush, these are massive simplifications).

You're going to spend $7000 to gain 30hp?

Pistons would be necessary for overbore, and the lighter/stronger rods would be for RPM durability, since the car is mostly driven at the track.

So far since the suspension work has been finished. It's seen 1.5 tanks of gas of street use, and 2 full tanks under full throttle 6k+ RPM track work. And over the next 6 weeks, there are two more track days coming up.

Keep in mind, I'm not steadfast for anything, I just want to get as much info as I can so I can contemplate my options.

I'm hoping the 1.6 will hold together all next season, then I can do something about power next winter. While aquiring parts over next year.

z31maniac wrote: Keith, any "build" would likely include cams, slight headwork, +1mm pistons with upped compression, aftermarket rods, and a standalone ECU for a proper 91 octane tune and the requisite intake/header/exhaust. Does the 160-170whp number sound reasonable with the above information? I figured that's approaching a $10k motor, but also figure an FM turbo, with the proper cooling setup for the radiator and oil cooler is basically $8k, plus a basic refresh on the current engine. The turbo would make more power, no doubt, but I think I'd really rather avoid that route. And I think a V8 Miata is just more power than I really want.

I'm not sure I agree with your math for the FM turbo. For the power levels we're discussing, you're talking about a Voodoo II. $3345. Add in a clutch, fans and a radiator and you're still under $5k.

With the recipe you've posted, it really comes down to what you do with the cams. Bill Schenker's legal CSP engine was built with similar specs (including a "stock" cam) and it pulled a maximum of 160 rwhp on our dyno on 91 octane. That engine had an enormous amount of dyno time on it testing things like the length of the intake tract pre-TB.

I'm one of the few people who has actually owned a 1.6 Voodoo II and a high compression 2.0 at the same time. They made pretty similar peak numbers, but the naturally aspirated mill had more torque. Definitely a different feel to each of them and I miss my high compression engine. But we pulled it apart for a refresh after a couple of seasons and it looked like a tired race motor. Wasn't showing any signs of low power or low oil pressure, but the bearings and rings were not long for this world.

I don’t think too many people question POPSTOY’s power claims, it’s his total insistence that the only way to get to 160whp is to spend $10k to do it. In almost every thread where POPSTOY swaggers in swinging his ‘my wallets bigger than your’s’ 100 lb. dick, up pops Emilio from 949 point out that his original track rat/rental made almost 160whp on a JY 03 engine, 99 head, Mazdaspeed cam, adjustable gears, square top manifold, MSPNP, JR header, no cat, exhaust and a decent tune.

Well that’s my perception from spending too much time over there