Jon’s NA Miata Build

My dad gave me his Miata. He has a long history of giving me cars. He doesn’t like selling them. I think it’s because there’s always little things wrong with them and he feels guilty about selling something that isn’t perfect and he knows I can fix them, so he just gives them to me. There was a 1984 Plymouth Reliant, a 1987 Mazda B2200 2WD pickup that said WordPerfect Corporation on the doors, a 1991 SHO Taurus I wish I had kept and now a 1994 Miata.
To him, I think it was just another 30 year old car with 185k on the clock and a squeaky speedo cable. I don’t know if he knew these cars in this condition are going for $8-10k on KSL. It had been garaged the whole time he had it (20 years) and was mostly a weekend car. It has a couple paint chips and some peeling on the bumper cover. Very nice shape otherwise.
It showed up in my driveway on the day the registration expired where he told me he’d lost the title when he moved and it would take him a while to find it.
I pushed it into a corner of the garage where it sat for almost a year. It’s bone stock.

jsudar said:

and now a 1994 Miata.

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That'll be the 1.8L engine. Stick or auto? And what are you planning to do with it?

When it first showed up, I had three different Ducati projects going on and I was overdue for building my growing daughter a new pedal bike— I scratch build custom bicycle frames so this wasn’t a matter of just bolting parts together. I didn’t have room in my life for a Miata. That’s why it sat for so long.
However, I had gotten a new job in Salt Lake City (I’m in Utah county) and was commuting in my F150–not great for gas mileage. I’d ride a Ducati when the weather was decent, but even my S4Rs only got 33 mpg because, well, I like to have fun….
So I licensed the Miata to use as a commuter. The manual trans kinda sucks on I15 in the evenings though and I had to build a custom cup holder for my morning coffee.
It only gets 31 mpg, because, well, I like to have fun…
It would probably get 40 mpg if I didn’t shift at 6k
After several months of commuting in it, I have determined it’s an underpowered motorcycle that doesn’t tip over when I stop.
It’s loud and vibraty, not particularly comfortable or easy to drive (compared to a modern vehicle) and I’ll probably die if I get hit in it, which is likely because it’s so tiny.
I finished my daughter’s bike, sold a Ducati and have a little motivation now, so I thought I’d start a build thread.

TurboMinivan said:

That'll be the 1.8L engine. Stick or auto? And what are you planning to do with it?

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The 1994 is arguably the best year of the Miata. They are the lightest/simplest cars that had the bigger 1.8L and the bigger rear end. The earlier 1.6 diffs were made of glass…
It is a five speed manual.
I haven’t figured out what I’m doing with it yet. At least not all the way. It will not be a dedicated track car. Needs to stay streetable.
It needs power. 100 HP to the ground is not enough. Rotrex supercharger maybe?
It needs tires, but has alignment issues like slipping eccentric bolts so I’m working on that first before I drop money on new tires and wheels.
I’m machining my own Delrin bushings and building my own upper control arms to eliminate the eccentrics.
And it will need a new clutch very soon because I drive like an ass….

I’ve always wanted to drop a built 2.0 liter TDI into a Miata.

Looks like a fun project!

Started with some fun stuff easy stuff because I like to make things. Yeah, I could buy all this stuff, but l love to build it myself.
Here’s a shift knob made from Delrin scraps from work.



And some door pulls I stitched up from a weight lifting belt I got at DI with custom aluminum washers. Saved 50 grams per door. I felt that gain in the butt dyno

Godzilla 7.3 swap. I said what I said.

Ecotec turbo build? Keep it running stock and then swap it?

Hickey said:

Godzilla 7.3 swap. I said what I said.

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The crowd I run with has a 2JZ Ultima RS kit car that weighs the same as the Miata but puts down 10x the HP and a ZR1 Vette that has a better power to weight ratio than my fast Ducati and runs low 9s in the quarter.
Don’t think it hasn’t crossed my mind….

jsudar said:

It needs power. 100 HP to the ground is not enough.

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Okay--I'm not saying you're wrong (as my own Miata project would attest).

But this raises a question: how much power will be enough for you? 200 WHP? 400 WHP??? What do you think?

Since the stock trans and rear end can only handle about 250 WHP and I’m not ready to do those swaps yet— I would like to hit about 230 WHP. That requires about 10 pounds of boost. Still going back and forth between a turbo and a Rotrex supercharger.
I honestly don’t think the chassis is good for a whole lot more than that. Miata’s are too short, narrow and flexible to handle 500 WHP. Donuts are fun, but only for a while.
It’s more important to me to keep it lightweight. A car with a lot of power can accelerate forward quickly. A lightweight car can accelerate or decelerate in any direction quickly.

Because I’ve been using this as a commuter and it’s not uncommon for me to spend 2.5 hours a day in it, I did some stereo upgrades. A cheap Amazon Bluetooth 240 watt amplifier and not so cheap 3rd Millennium sneakers.
Made an aluminum plate to plug the hole where the stereo used to live. Amp control is on the right. Working on a phone holder for the empty space on the left so I can use navigation.





And finally, a power antenna delete. The amp is Bluetooth only, so no need for an antenna. That’s a stainless plug for a 1/2” conduit penetration in an electrical cabinet. Fits perfect.

My Miata experience... a turbo on the Miata engine is plenty of power!

I think there's a longer video on these two cars. I can't seem to find it now. Fun to watch Randy put them through the paces. No matter what you do, this will be a fun car.

Bought this stuff at the Ford dealer today. Cost me almost $100 for three quarts.



Was is worth it? I’ve only driven the car ten miles, but it transitioned the tranny back to sweet, smooth shifts. Can I say that?
It’s so good. It has sigma rizz. Definitely not from Ohio. No cap. If Jesus had turned water into gear oil instead of wine, this would have been the stuff.