I wanted to know if anyone here has cryogenic treated there 5 speed to help make it stronger. I know every one here would say six speed but i am unable to swap my 5 speed for a six speed as i have a rotary. Now you guys will say swap to a turbo tranny but tat would cost money and lots of fab work. To do a turbo tanny swap i would need a new flywheel, clutch and a bunch of mounts as i wont be able to run a ppf.

So i want everyone opinion on cryo treating the rx7 NA 5 speed i have. From what i read it should make the tranny strong enough to support what i want for a power goal and not cost an arm and a leg.

This is what the company i have been looking at says for transmissions.
Transmissions: Cryogenic treatment of transmissions will increase the life of all internal parts as well as the casing. Gear failure and wear will be reduced. There have been reports that smoother shifting and better clutch performance have resulted from transmission treatment. Treatment is available for both automatic and manual transmissions.

http://www.nitrofreeze.com/racing.html

As i have a 13b i get to say its a 2cly =] so it would only cost 65 bucks.

 

From everything I heard/read about cry-o treatment the strength increase really isn't nearly as significant as you think.
Tooth design, gear width, and gear ratios play a much bigger role in how much torque the transmission will take before calling it quits. Obviously the shock loads you put on it are aloso a huge contributor.

I haven't heard of a single person taking apart a 5 speed to do something like this.
I just have a spare sitting in the garage "just in case"
good luck

 

The n/a RX-7 transmission's weakpoint is the construction itself. Your best bet would be to rebuild a spare one with stronger parts...but for the price/effort, that TII tranny might be looking like a better option. IIRC the na/ FC and the NA Miata use the same gearbox..same with the older B-series trucks. With that said, you'd be better off asking on RX7Club.com since they deal with RX-7 transmissions more than we do.

 

The reasons i dont want to do the turbo tranny is i dont want to have to sell the nice light weight fly wheel and clutch i just got. Also i want to keep the ppf on the car. The tranny would coast around 200-350, the flywheel and clutch would cost me around 600-800 and then time and money to build mounts for the tranny and diff. Also i dont know if i would need to shorten the drive shaft that 50-100.

SO that would cost me around $1125.00

 

Also the TQ from a rotary is nothing like a piston engine as its a smoother TQ and the TQ numbers are lower then a 1.8l would be.

I also have an extra case for the tranny rx7 bell housing, rx7 gear case and miata tail housing.

 

then why worry?
Get a spare for if it goes, and just rock the current setup.

I think you're at a place with your car where you either spend some serious cash to beef up the drivetrain or stay as is.
Stuff like cry-o on a weakling 5sp IMHO will add what, like 50ft-lb more torque capacity? Don't quote me on that but I'm positive it wouldn't be something drastic.

 

Ditch PPF and impliment a transmission crossmember using some frame braces? That would sove that. How much will stronger internals cost you as well as building a transmission compared to that? If that clutch/wheel is so nice, then you should be able to turn it for a pretty penny toward the needed parts for the TII trans. The peace of mind that knowing you have a capable transmission is worth it too. Don't band-aid someone else's poor planning, fix it.

I had a FC GTU and killed 3 transmissions...with basic upgrades in power. I couldn't imagine the n/a trans coupled to a whopper turbo setup being very happy. It would be like doing a STi swap into a WRX but leaving the stock WRX transmission...

 

I work part time for a performance transmission shop and we only cryo treat when the customer has more money than sense. Same for REM-ISF treatments, though to a lesser degree, and we do a bit more of that as it does actually net some tiny friction advantages. 18psi's comments regarding gear and tooth design are in line with everything we see vis a vis gearbox destruction. If there's a heavy duty gearset available then that's probably your best bet.

 

I could do the miata quaife gearkits as the rx7 is the same thing. but thats big bucks$$$$

 

My point exactly.

 

PPG gearset for the miata.


Straight cut gears, bud.

 

I believe Gary / TDR sprung for a cryo-treated ad REM polished (rimjob) 5-speed and I'm fairly certain it puked immediately. He's now on a 6-speed.

Do whatever you want to attempt making powdered-metal gears stronger, I'll continue racing on my 6-speed.

 

Hustler i wish i could run a six speed tranny. =[

 

Does PPG really sell a gear set for the miata?

 

Yeah I think they do, I think it is supposed to be used as a dog leg setup with 1st where 5th normally goes.

 

yeah your right they do sell it as a dog leg setup also they dont list a price and you need to have a minimum order of 3. =[

 

What????? Flywheel clutch $$800????

Spare 6 speed? Sell me it now

 

No. spare 5.
I will not own another 6 speed again unless its paired to a 3.6 rear end. 4.10/4.30 its just god awful

 

the RX-7 Turbo trans is unbreakable in a 2000lb car. Use it.

 

rotary lightweight flywheels need counterbalancers. extra $