Mythbusters: Miata Style
 

Curious to hear from anyone here who has converted a 90-99 to a 6 speed manual from a 5 speed manual. Specifically, I'd like to know if you used the plate that goes between the motor and trans from the 6 speed car, or did you re-use the 5 speed plate?

I know what the conventional wisdom is. I don't think it's true. Looking for knowledge from those who have actually done the conversion, not anticdotes from what you heard some guy did once.

Boy, what a letdown. I saw that title and thought "Wow, Adam & Jaime are going to shoot Miatas out of a cannon, or strap rockets on them, or try to jump them over things. Or at minimum cruise around San Jose and see how many guys vs. girls talk to them... "

I will have first hand information in the next few weeks!

I know, and I'm sending you the plate anyway. But to me it looks like any 1.8 plate would work with a 5 or 6 speed.

I thought the plate was needed because the starter location was different between the 5 and 6 speed.

+1 for a disappointing thread, the title was misleading. :)

I think all the NB plates are the same, 5 spd and 6 spd

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I know what you mean, ive gotten mixed info on this topic a million times and would love to know the real anwser.

If the starter is in a different location then the mounting holes for the starter would have to be in a different location on the block... making to swap considerably more difficult.

we held up a 99 6-spd plate to a 03 5-spd plate and they looked identical

maybe look up part numbers and see if they match?

I have. They do.

i have first hand info on this... i just used the 5speed plate. as stated above the only difference is the one starter bolt hole. otherwise, its the same. also the sensors are in opposite locations and the connectors need to be swapped with one another. otherwise every time you go in neutral your reverse lights go on. otherwise, its a plug and play deal. even with all 1.6 stuff. i still run a 1.6 clutch on mine.

I did the swap 2 weeks ago. I reused the 5-speed plate from my 96, as well as the starter. There was one bolt that did not line up, it was one of the small diameter bolts that went to the starter. This bolt has been stated before by Markp. I didn't reinstall one of the wire harness brackets, I think it was the bracket that the left off bolt connected to. I ran a couple zip ties through the semi-open hole to secure the harness in the area. Otherwise that's about it. The turret doesn't require oiling like the NA 5-speed. A cleaner way of filling the 6-speed is to pour the fluid into the turret while the fill plug on the tranny is open, with a pan beneath it. I had a hand pump and did the fill from underneath, and as usual, I made a mess, even with the pump. The fill plug is in a more difficult to reach area than the 5-speed plug was located.

Shifting is smooth. The additional gear may be better for track use as it will probably maintain the rpms better than the 5-speed, heel and toe seems a little easier since I don't have to blip the throttle as much, less rpm change between gears with the 6-speed. I have to get used to shifting into the additional gear, and also that 4th gear is like 3rd with the 5-speed, etc. I notice I drive with the rpms a little higher than I used to. I think the 3.63 gears would be pretty darn sweet with this transmission. I am still running the 3.90s.

:eek5: i didn't think that was possible!

does this apply for 1.6s?

My guess would be this:

Thanks for the impressions! I've been wanting to do this for about ever. I have the 3.6 gears sitting in a box, going from a 5 speed with 4.1 (4.3?) to a 6 speed with 3.6 should be amazing - it'll make 2-4 just a bit lower, 5th about the same, and 6th a bonus gear! Which will mean 2nd will be a bit less useful, since right now it's my "you thought you could hang with me?" gear since it's so tall it just keeps giving.

Odd you run around higher reved - I guess the next gear isn't worth getting into yet? what year car is it out of? I've heard the 6s aren't as smooth and good to shift, which has been the major reason I've been holding off.

I have to get used to the 6-speed, not that I enjoy revving the engine more than needed. I only have about 150 miles on it right now, and a few times I've noticed myself not shifting into the next gear, I assumed it was from my habit of driving 5-speeds all the time. My 6 shifts pretty darn smooth, maybe not as precise as I'd like, but pretty darn smooth. I've also been skipping gears. With the 3.90s the gears rev out more quickly than the 5, so I've been going from 1 to 3 or 2 to 4. I had a short shifter on the 5-speed, so I can't recall how smooth it shifted with a stock shifter. Getting into reverse seems to takes a little more work than with the 5. So far I am pleased with it. I hope it is as tough as other people have said. The case is definitely stouter than the 5-speed's. I have to look at the paperwork, but I am pretty sure it's out of a 2002. It had about 11k miles on it when I installed it, according to seller.

What did you pay for it?

Oh, man, I bet the long shift is a killer. I have a C's short shift (mazdaspeed) on my five, and it still feels too long, but livable. It's a displaced fulcrum, not just a shortened arm.

I guess that's the other thing keeping me out of a six. Then again, maybe with the extra row in there, it makes more sense?