What does the additive provide beyond the lubricant? Does it protect the synchros or allow them to perform better?

 

Wrong GM part number, should be 1052358. Recommended to me by a guy who builds Spec Miata transmissions. Seems to make the syncros work a bit better, shift faster.

 

brb, swapping the 6-speed.

edit: false alarm, awaiting machismo's gentle touch this weekend.

 

lol@tags. tee hee

 

Neo Synthetic.

jeff

 

H, what clutch, shifter, etc are you going to run? Definitely one pleasant thing about the swap is not having to fill the shifter turret anymore.

 

+1 on the Redline. It's pretty good stuff. Just be sure you get plenty of room under your car when you change it. I didn't do that and it turned into a messy nightmare.

 

amsoil 75w90 MTX is good **** in the 6-speed. Cruising on the highway sucks though.

 

I noticed the 6-speed I put in my car shifted well. Now I'm going to tinker with fluids to see if it can improve more. First gear is useless with 3.90's. I skipped gears, as in started in second, then went to fourth; if in third, I would have shifted into fifth. Cut down on rowing through the gears. I didn't skip gears very often with the 5-speed.

 

I think my car is into 300whp+ now, maybe 290wtq or so. These gears are way too short with the 4.10 rear end. Its nice to flog the car a bit now and not worry about it puking gears.

 

What happened to the 3.6 gears you were getting?

 

The guy who's putting them together for some reason has issues I don't understand because I'm just a caveman. Apparently the pinion shank is too long and won't fit in the pumpkin.

 

I remember you had a thread on your engine build. Care to link it? I'd like to see what you did to reach 300.

Wow, 4.10s and the 6 speed make for very quick shifting.

 

6spd@4.1 FTL... I may be blowing my diff any time this or next year as it's already whining loudly at 40mph. Waiting for you to blow yours and looking forward to your endless discussions on final drive ratio's before you finally put one in

 

If/when I have my gears installed, I'll be putting the 3.90s up for sale. Eventually, some day...

 

https://www.miataturbo.net/forum/t28293/
I haven't put down a 300whp pull yet. However since i did the last 261/252 pull on the dynodynamics I've added COPs and the car started spinning the tires in 4th. Then, I leaned out to 11.5:1 on the top rpm range. Then, I fixed the gasket problem. I have no doubt that its putting down 300whp on a dynojet...if not I can always turn the boost up because I've had it at 19psi and the car wanted to skate on the highway in 4th.

 

BTW, Amsoil sells Slip Lock differential additive, same as the GM product.

 

5th gear synchros are not happy, what should I do?

 

https://www.miataturbo.net/forum/t28293/

 

For starters, here's a quick couple of things to check:

Bushing on the bottom of the shifter - any grooves or anything will cause it to bind and make it seem as if the synchros aren't happy.

Lower shift boot - when mine was falling apart is would bind on the top right side making 5th seem like there was a problem.

What fluid did you go with? Try the motorcraft fluid if you haven't.

Shifter orientation - make sure the dot is facing forward on the shift lever.

This is all basic **** that you already know, but I often times find myself over thinking stuff like this.