S2000 drivetrain swap
 

It's been done before, so not a serious step by step blog, just some photos of problems solved to allow this great engine to join forces with the Miata chassis. The big issue is the different design in the oil pan, with the Mazda having the forward cutout oil pan that allows the engine to sit over the steering rack's rearward position, (compared to most cars), while the Honda's deepest section being the front. I didn't want to get involved with a pan swap, and all the changes needed to accomplish that, so moved the engine as far back into the chassis as I felt rational. I wanted to keep the wiper function, so that became the deciding point for stopping the metal cutting. I also wanted to create some more room to get a header downwind out of the engine bay, so a fairly big cut had to be made on the passenger side of the engine bay/ trans tunnel. Once that was done, I could see how much the steering rack had to move forward, to clear the oil pan. Not wanting to mess with the steering geometry any more than needed, I ended up using a V8R front sub frame, and cutting out the rack mount, and moving it 2 1/2 in. forward. I have found another guy's build, and the photo's looked like it was moved more like 5-6 in., and apparently the car could still be aligned to drive, so I think I'm OK there.
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Once the cutting was done, I welded up the new tunnel, and painted the engine bay, and while the weather stayed nice, the rest of the car. I sent out the subframe to be powder coated, along with the rest of the suspension, and am now waiting for 949 to have the next generation of their 863 suspension bushing kit available, so that can allow me to put the suspension back in. The shell got a new windshield installed, as the old one was cracked.

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Finally, yesterday was a long awaited re-installing of the drivetrain, which gets it off the garage floor, and let me make the trans mount, and start thinking about the header fabbing. Always great to put the engine in for keeps!
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Do yourself a favor and throw away all that fuse box/relay bullshit and buy a decent PDM. I do a shit ton of wiring, everything else looks great, but that made me cringe.

Looking good, can't wait to follow your progress.

What are you planning to use for tuning? Tuning options are terrible, but my '01 was running +14:1 at WOT with a testpipe and intake. This was a couple years ago, but I talked real sweet to Reverant, supplied him with a stock ECU, and he built me a megasquirt that's worked great for me.

I am using the stock ECU; it runs great and since I'm not shooting for mega power will suit me fine. I built a MG Midget project with this same drivetrain last year, but once it was finished needed something to work on, and ended up robbing the drivetrain, seats, gauges out of her to start this Miata project. For me, the package is a known quantity, and I'v done a LFX Miata, and an early NA turbo, so am pretty used to working on Miata's. I'm looking forward to all those rev's in a reasonably light car.

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Seconding Curly's comments, both on the build and the PDM.

I presume you are building it as a track car, and not shooting for rego?

Spridget looks good, how much did that weigh - must have been a rocketship!!

The Spridget was cool, thanks, and weighed about 1500 lbs. The Miata will be a street car, and will see some track duty as well. I was able to find a roller with a little rust in the rear rockers, but otherwise rust free. It had no top or drivetrain, but was a good shell to start with. I have retained the wipers, and all the factory lighting will work, and the engine controls, but that's it, so it will be a basic, simple ride. The engine set back dictated the loss of the HVAC items. On the wiring, I'v probably done 20 cars over the years, and understand circuits and relays, and have no issues with the finished product, so will follow that path, despite maybe getting beat up over it. Modern cars have so much wiring going on, that I have to gut the thing and start from scratch, rather than sift thru all the circuits and keep parts. Being red/green color blind doesn't help with that. I'v found a Torsen diff, and swapped that in, and the front brakes will get the Wilwood treatment. It will look pretty stock, and should be a little lighter than stock, 'tho the Honda drivetrain is around 40 lbs. heavier, if I remember right. A past project was a Seven clone with the 2.2 Honda, weighing just over 1000 lbs.; THAT was a rocket! Just wasn't as pretty as a NA.

Progress and a question
 

A little more progress, getting things off the floor, and back into the car. Diff brace made, and diff mounted. Rad installed, so now can make some shrouding around it. One question: are the parking brake cables crossed, as in the driver's side mounted crossing over to the pass. side, and vice versa, or do they stay on the same side as their location in the tunnel. Car came apart, so I have no notes on that, and can't find any online photos that show the instal.
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I don’t recall there being much slack in the cables, so they probably only fit one way. That said it shouldn’t matter since they’re pulled in tandem regardless.

What radiator is that? Looks ideal for my K swap setup…

Thanks for your info on the cables; finally got them sorted an hour ago. The rad is for an early VW Rabbit,1975-84 ish., Ebay aluminum version. Have used them on other projects, and they work well and are pretty cheap.

Nice build! Subbed for updates.

You made that custom firewall look easy, clearly you've got some fab experience!

Thanks! It's an addiction that's hard to shake, but is my favorite way to spend time. Probably spend more time dreaming and working on them than driving,( which shows a confused set of priorities.)

I hear you there, I always have a car project of some description on the go.
You have to have something to be passionate about in life!

I have a lot of admiration for folks like you who just can't stop building. I just want to ride/drive, not wrench! But if you love projects you'll never be bored.

I guess the downside is the $$ loss every time; I joke to my Wife that I should just ask someone if I can build their car, and give them $10K when it's done, as that's about how it works out. Still, it beats a gambling addiction, crack, etc. and I have a hard time not shooting right down to the garage as soon as I wake up. And these are great cars to work with! You are probably a lot smarter with the ride/drive approach!

Progress
 

Wiring now 100%, plumbing is also finished. Gave up waiting for the Supermiata suspension bushings to arrive, and ordered the Superpro kit so I could get the corners back on. It looks like a good design, so am happy with it. Bodywork back on, so finishing up the exhaust is next.
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Looks clean, I'd maybe wanna throw a heat shield between the relay bank and the manifold, and I'd also suggest some sort of intake tube. Filter right on the throttle body really kills power.

Any guidance the intake tube? I have a fair amount of room to 90 off the TB, but with the stock front bodywork (which I like, and don't want to mess with) don't have a good way to make a cold air box. What issues does the filter right at the TB cause? Thanks for pointing it out!

The filter directly on the TB gives super turbulent airflow, you ideally want enough length for the flow to straighten itself out and become more laminar. I was able to snake an intake tube across and down to behind the passenger side of the front bumper;
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pops out right here and Is anchored to the front timing cover, so it can move with the motor