Well I sold the S2000 a little over a week ago, she's off to a new home in Virginia. My ex-daily driver, a '90 Miata, is now in the process of being converted into a little monster. Meanwhile, I filled the daily role with a '96 Prelude Si. Hopefully you guys won't oust me from the community. I miss the car dearly and will always have a special passion for S2000s.

I started off my project by ripping out as much weight as I could. Out came the AC, lines, condenser, fans, power steering, interior, passenger seat, gutted the trunk, convertible top, wimpy stock tow hooks, spare tire and jack, windshield wipers and motor, side windows, and I'm sure more stuff that I'm forgetting. As of now I've dropped just over 200lbs off the car, right at a 10% reduction from the 2071lb curb weight.

From there I started to tackle the handling. I already had springs, adjustable shock, and sway bars on the car. From there I installed flying miata's butterfly brace that really tightens up the car. It's starting to feel more and more stiff and solid, almost S2000esque, just a lot lighter on her feet. I went ahead and bought some R-comps for autocross. I've got a brake upgrade coming from flying miata as well, and a much needed LSD conversion from Mazmart. Rollbar, harness, racing seat, and steering wheel should be soon to follow.

With weight reduced and handling improved, there's only one thing to do, add power. Compression numbers on the stock 1.6L came back 185, 165, 145, 185, so I started looking for a newer 1.8L motor. I found a '96 motor with 80,000 miles on it and should be picking it up tomorrow. Once the motor is in, I'm planning to throw around 10lbs of air at it and let it scream.

The end goal is basically a streetable racecar. I'm not going too crazy with the power. Something around 200hp and 1850lbs is where I'd like it to fall. I figure that should give me something pretty close to what my S2000 was in a strait line and will absolutely walk all over it in a turn. At, yesterday's test and tune autocross (on street tires) the 85ish whp Miata was just 4 tenths off what I ran last month in the 325whp S2000. The future for the Miata looks very promising.

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Wow, very cool April has an early 90 Miata too
The stock rear diff for 1990 has a 4.3 gear and ours has the LSD from the factory.

How much is the LSD from Mazmart? are you changing out the full rear or just adding the LSD?

 

Sorry to hear you sold the S. Good luck with the Miata it should be fun to track and there are a lot more Miata Forums the S2000 forums to give you ideas.

 

I'm changing out the whole rear (axles, diff, driveshaft) for a 1.8 torsen out of a 94-97 with a 4.10 gear. There's only so many of them out there and a lot of people are after the upgrade. I paid $1050 + $75 shipping and as I understand it, it's very similar to an S2000 differential (Honda sourced their diffs from Mazda). Maybe you should consider some horizontal integration into the Miata market?

S2000 diffs seem to be much more abundant and cheaper than the torsen Miata diffs, and they're supposed to be stronger too. If you could figure out a retrofit kit for an S2000 diff to a Miata it could be a gold mine!

 

I do work on the Miata diff too. The S2000 diff is the stronger setup with a 28 spline LSD. The bearing caps and gears are the same between the two. You can bump up to a S2000 LSD and 28 spline axle set in your Miata
We had the 95 Miata with the 1.8 and 4.10 before we got the 1.6 90 with the 4.3. April likes the 90 better, she says it's a faster car than the 95 was. I have driven the car a few times and the off the line pep is better than the 95

If you deside to go to a 4.3 or 4.44 let me know and I can set one up for you

 

With the power I'm shooting for I think the 4.10s should be good but I'll let you know if I need something a little shorter.

 

Did you have to do much to install the flying miata's butterfly brace? Do you still have a factory cat? I would like to install one on Aprils car, we have the 95 to 97 brace that goes behind the seats already but, I bet that butterfly brace would be a big plus

 

I do have the stock cat and it wasn't an issue at all with the brace. The brace does hit the header really bad though. I had to adjust the brace all the way down and it was still some work to get it on. It did tighten the car up a lot. I'm hoping it gets better once I get it swapped and turbo'd but we shall see.

 

I may go for the brace for Aprils car, maybe I can do a little moding to make the install a bit better around the header.

I will be in the shop tomorrow building a 4.77 out of the AP2 housing I got from you. I am building the rear for my self because, I have 600 miles on the 4.3 build that is in the car now so, it is time to pull it The 4.3 is a real nice gear in the S2000 it should have got this gear in the first place

 

The 4.3 should really be better for autocross. Even with the power to weight, it should be a great gear. Get with Puddy he may be able to show you the difference.