Why not MZR NC Miata engine into an NA?

In reply to z31maniac:

but winter is car building season and summer is car driving season....

Well parts aquiring would start next summer, I wouldn't have the $3-4k necessary for the swap ready for this winter. The hope is that the current engine will last through next HPDE season, then I can do the swap and put a Torsen in the car while I'm at it.

But I had prepared her for the garage to start filling up with parts starting next summer..................not now!

psteav wrote:

racerfink wrote: Just a simple home fabricated tube with an AutoZone cone style air filter, and DynoShop straight exhaust on my '90 short-crank motor with 196k on it, bumped the hp to 112.8 at the rear wheels. That was pretty decent power for Spec Miata back when I first built it. And it was a completely original motor inside as well.

I'm not calling you out, but wow. That's about 20 hp from intake and exhaust....Maybe the dyno's a little off? IIRC, a strong stock-stock 1.6 dynos 92-95 at the wheels, based on the dyno....that's pretty impressive.

That's what the dyno at AutoTechnik said. Most of the "built" 1.6L SM motors these days are making 122 at the wheels. That's taking about 20 cranks, 100 pistons, 100 con rods, etc., measuring them all, and putting the lightest ones in a motor.

I had a street motor I bought, and had it refreshed (didn't open the bottom end), and it only made 108hp on that same dyno.

Sorry to bring an old thread back to life, but this was an interesting thread. I really like the idea of putting a 2 or 2.3 liter Duratec into the NA.

Yes its a lot of work, and yes it may not be worth while but it seems that its a toofer of a swap, ie you save weight, and you increase power, with most of the other purposed swaps you are adding power at the expense of additional weight.

Given that FM claims that you can add a GIANT aluminum blocked v8 to the miata at a remarkably modest weight cost, I would think that some significant weight savings could be had with a small aluminum blocked i4.

Now I know that internet sourced engine weight numbers are notoriously unreliable, but as a first cut: does anybody have and idea as to what the duratec engines weigh? how does that compare to be BP weights?

Capt Slow wrote: Now I know that internet sourced engine weight numbers are notoriously unreliable, but as a first cut: does anybody have and idea as to what the duratec engines weigh? how does that compare to be BP weights?

The only part that's likely to be significantly lighter is the block, because that's part that goes iron -> aluminum. A BP block is heavy, but it's not that heavy. I'm a wuss, and I can pick up an empty one by myself. You can also ship them UPS, and I think the weight limit for that is 70lbs.

So let's say you cut the block weight in half, that's 35 pounds. Is that and 30hp worth a hundred hours of custom fabrication?

(BTW, the LSx engines aren't really all that giant. Being cam-in-block OHV really cuts down on the size of the heads).

I once figured how much weight you'd save with an aluminum block BP engine. I forget the number now, but it was pretty minimal.

I'd be more worried with the height of the MZR. The S2000 engine is very tall and causes clearance problems both top and bottom. I don't know how the MZR compares to that, but it does have a pretty long stroke. The 2.3 is 11mm taller than the 2.0, BTW.

My apologies if this is a repeat, I did not read all 4 pages again to refresh myself on previous discussion of the topic.

drat, I was hoping for a little more weight savings than that, It would be pretty fun to have a streetable miata that had ~10lbs/hp and only 170 hp ;)

So dragging this one back from six years dead I was looking for information on this I came across a car called Donkey owned by one of the V8 Roadsters guys.

The 2.0/2.3/2.5 will fit but may require boxing in a section of the firewall. Everything written about the swap was either a V8R ad or vague but the MZR looked quite at home even with aftermarket NC parts (modifications required)

I think the 2.0 and NC 5 speed will do well to power the heavier than an NnA but lighter than a NC Panhard.

I've been thinking about this swap for a project of mine. The Duratec has some real hotrod capabilities developed over the pond, and if you HAVE to keep the car all-Mazda it would be an interesting option. Keep in mind that the V8R car was a track rat so it was never really finished and compromises were accepted that wouldn't usually pass muster in a street car. Still, there's an MZR engine and NC trans and NC subframe in my shop right now, waiting for some test fitting...

As noted, though - if it doesn't have to be all-Mazda, there are a lot of other really compelling options that are the same amount of work.

Keith Tanner said:

alfadriver wrote: Thinking about it more- is there an aftermarket part that fixes the iVVT into a single location? It appears that if you don't connect the VVT, it goes to full retard, and most of the gains are found from advancing it. So it would be interesting to see what would happen if you got it to say, +25deg and kept it there.

There's a Megasquirty VVT controller. You can easily fix the VVT into full advance electronically - I think the crude method is to treat it like VTEC (yo) and switch it at a certain RPM. It's the in-between stuff that's tricky!

I don't recall if we still have the dyno numbers around from testing the VVT controller, but I remember the overall trend. It didn't do anything for top end power, but was a significant help for the mid-range at full throttle.

One of the benefits for me is the option of increasing engine size beyond 1.8L. The Panhard is a four door and will be used to move 3 to 5 people. While it will be mostly Miata it is a sedan that will be used as a cruiser. That extra torque from a 2.5 would be an excellent choice.

Keith Tanner said:

I've been thinking about this swap for a project of mine. The Duratec has some real hotrod capabilities developed over the pond, and if you HAVE to keep the car all-Mazda it would be an interesting option. Keep in mind that the V8R car was a track rat so it was never really finished and compromises were accepted that wouldn't usually pass muster in a street car. Still, there's an MZR engine and NC trans and NC subframe in my shop right now, waiting for some test fitting...

As noted, though - if it doesn't have to be all-Mazda, there are a lot of other really compelling options that are the same amount of work.

 

If it works, it would be a great swap for my '99 if I ever kill the original engine.  Which I'm really trying not to do....

But take an early car with a 2.0/2.3/2.5, and put taller gears wherever you can.  And I bet you get a lot of performance and pretty darned good fuel economy.  I know how I'd like to calibrate it....

I have had a turbo NB.  I currently have a 2.5L NC.  

As someone who has had both, I would not do a MZR swap into a NA/NB.  If I was going to go through the effort of an engine swap it would be a LFX/LSX or a S2000 motor if a 4 cylinder was a requirement.  I like the MZR motor within the context of the NC because it is "good enough" and plays nice with the platform.  Outside of the platform the value proposition really falls apart in favor of other motors.