02semiata

Hey guys I just picked up a 90 5speed transmission with shifter and I will be putting it into my 02 6speed miata for auto x reasons. I just wanted to know what I could use from my 6speed and what I need to buy to complete the swap. Thanks

emmi

take everything incl. the torsen and throw it into the na

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02semiata

What NA ? I got a 5 speed tranny not the whole car

socal858

i think everything should just swap over, i met a guy that did that all he said was the wiring was different.

( not really sure soo.. yea, i think there was something on miata.net)

02semiata

Like in the garage section of miata.net

socal858

i think so. its probably a 5 speed to 6 speed but i'd just assume you'd just do the opposite

02semiata

Yeah I keep finding 5 to 6 stuff when I google the subject . I didn't see anything on miata.net though

socal858

oo sorry i dont remember where i saw it. but i did find this on a thread

You'll need a 6 speed transmission, engine backing plate, starter, shift lever, and shift nob from the donor car. The reverse light switch harness is changed so you have to make one splice to have back-up lights. The mechanical speedometer drive from the NA (so keep yours if you give away the 5 speed) will go right in the hole in the 6 speed.

so just have everything for that but for a 5 speed. i think sorry

02semiata

Thanks man

02semiata

Ugh I need like a parts list haha. I really want to use my sensors from my 6 speed and just get a new speedometer drive. Also I have no idea what this engine backing plate is.

3MiataFamily

Hold the phone..

to swap the 5 speed into your '02 in place of the 6 speed..

Remove the 6 speed..swap the backup light switch into the 5 speed..swap the speedo gear drive from the 6 speed into the 5 speed..(direct fit on both)

Install the 5 speed into the car.

no need to change the engine plate..or the clutch ..or the starter.

the starter will mount with 2 bolts instead of 3.

re-use the driveshaft..it will fit right in.

That is it.

the only thing I would be concerned about is the choice of the 90 5 speed. they are more prone to the 'stuck in reverse' problem than the later 5 speeds.

02semiata

Thanks!!! I am using a 90 because I got it for 50 bucks from a friend I auto x with. He sold his miata but had his spare tranny left over. If it goes the 6speed is going back in and I will shop around for a 99+ tranny. Thanks again man

unevolved

This can be the worst part. They both use three bolts but only two of those three actually line up. The difference is only about 1/2". If you're not paying attention, you'll sit there for about half an hour trying to figure out why that last bolt won't go in. Don't ask how I know.

Blackbird

I did a comparison between miata 5 speed and 6 speed transmissions on the Locost forum.
Here's a link.

You'll need the shifter and gasket plate of the 5 speed as well for the swap, the one that is getting sandwiched between the engine and the trans.

BTW, since you're doing it for competition purposes, I'd recommend going with a 5 speed from 95-up because of the increased amount of syncros - they just shift nicer (unless abused, of course).

Moti

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02semiata

Thanks also I posted why I have the 90 trans

Flyin' 92

OP - Assuming you have a 3.90 torsen you'll want to ditch that for either a 4.10 or a 4.30. The tall gearing in the 3.90 won't allow your car to accelerate as fast as it would if you had either of the 4. diffs. If you can find an NB 4.3 Torsen that should be a straight swap without the need to swap over the axles and driveshaft.

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moreboost

Flyin' 92 is right, but the ratios of the trans are going to make a bigger difference.

The 4.3 is 10% shorter than the 3.9, so you'll get a 10% torque jump by switching to the 4.3...

But 1st in the 5 speed is 16% taller than 1st in the 6spd, and 2nd in the 5 spd. is 17% taller than 2nd in the 6spd. That's going to be a big difference in acceleration. About 16 and 17% percent, actually. Do you have FI or smaller tires? I'm willing to admit that I don't know what I'm talking about, and the net effect may be positive on your average auto-x course because you can hold a gear longer.

FWIW, I just did the opposite swap for my tired, torque-less wonder 1.6 and it's an absolute hoot to drive on the street now. But that's not auto-x, so I don't know...

The above posts are correct. If you're willing to use 2 bolts in the starter, all you need is the trans. and shifter. Even the shifter is negotiable depending on the model year of the 6-spd.

dnationb

So...are you selling the 6spd?

02semiata

You are correct but dont worry about that. I am putting on a supercharger for extra power so it should be okay in the end. The gearing should be good for around 64mph in 2nd and thats at stock redline. When I raise it next year I should be able to hit 70

02semiata

Na thats my backup for when the 5speed blows up. I hope it makes it the whole season haha. If I like the setup I will shell out the coin for a nice 99+ 5 speed

Flyin' 92

I drove a '95 with a 6-spd and 4.3 and I was shifting like crazy at my track day. The biggest problem I had was remembering that: 1st = Way too short. 2nd = 1st (in a 5sp) 3rd = (2nd in a 5-spd) and so on. It really messed me up the first few laps trying to get the feel of the 6-spd.

Even with the added power the car will still feel a tad sluggish off the line. Trust me when I say a 4.1 would be a better choice. It should provide a nice middle ground between the faster 4.3 and the slower 3.9.

You may be able to hold a gear longer, but when you get on the gas you might not get the same "burst" of speed as you would if you went with the shorter rear end gearing.

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02semiata

We will see how it goes. Worst comes to worse I will go with more power haha. I really wanted a 3.63 with my 6 speed but its to much money and rare so I went with the 5 speed swap. My other friend has a MSM with a 5 speed swap and the 4.10 rear he likes the setup. He tops out at 70 in 2nd but he also revs to 8k lol

moreboost

Yeah, I don't doubt it. I bought the transmission from a guy who had it hooked to 1.8 and a 4.3 Torsen, and from what I know about him, probably drove it almost exclusively on the track. He sold it because it was too short to be useful. That being said, it's a blast on the street with a 1.6 and a 4.3. 1st is almost obnoxious, but I knew that before I put it in. If I'm driving sedately, I'm out of first half way through an intersection. But if I put my foot into it, it's fantastic. This drivetrain combo really rewards driving like and ass-hole

I'm impressed it only took a few laps to get used to it. It took me a few thousand miles to get used to the 6 spd. It's surreal to try and drive a car that you've been driving for 7 years, and all of a sudden, not be able to pick the right gear going into a turn.

OP: Good luck with the swap, glad to hear it's gonna have a super charger.

Flyin' 92

That pretty much sums up my first couple track sessions haha

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02semiata

I have driven both 5 and 6 speed Miatas my car feels good right now with the short gearing but it's slow and your always shifting, fun but not fast lol. It was good on the track but my new combo will be better everywhere i feel. I hope....

saedrin

I've got a 4.3 and 6 speed with a turbo.

Total PITA, first is completely worthless. I can drive every day using 2/4/6 only. Wahhhh I want a 3.9.

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Flyin' 92

I wish the 6-spd had a taller final drive than a shorter first drive.

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