Just curious if anyone here runs his transmissions in high hp builds.
I currently have his 5 speed tranny in my car, probably looking on making 300 ~ 350hp , probably 290~ torque.

He states that he has other customers running the 5 speed in much higher HP setups and it holds.

Not only did the transmission get coated, but he also said that he changed the splined sleeve to a much thicker sleeve. Which doesn't allowing the counter shaft to twist and misalign the gears, and as a result the 5 speeds can handle much more abuse.

anyone here running one?

 

I dont remember the name and i lost the bookmark, but there's another company that swears they can reinforce 5 speeds to 400+ whp
I have yet to see anyone run them on anything more than hearsay

 

The group was https://walter-motorsports.com/ but I haven't seen much news on how successful/unsuccessful they were.

 

Their stage 2 option is pretty much what jo offers for all his trans.



curious to see how this trans holds up to 300hp

 

Well at least it looks like a new custom input shaft, hopefully it is made of unobtainium. I am curious to see how these hold up as well. Happy to do some load testing for one of these "built 5 speeds."

 

One of these transmission companies really needs to get one of these "350whp" 5 speeds to someone in the community that will test it. The price doesn't scare me at all if it were proven to hold up. I'm skeptical still and I'd probably put the money towards a 6 speed/3.6 combo instead.

 

well your in luck, I have jo's beefed up 5 speed in my miata right now. Looking to make around 300 to 350hp on my build sooooo, hopefully she holds. Just got to do some final things on the car before tuning.

Jo does both 5, and 6 speeds for about the same price. But he swears that his 5 speeds are the better choice, and that they hold up a bit more stronger then a stock 6 speeds. His 6 speeds only get coated gears though.

will be sure to update once I've put a lot of miles of heavy abuse

 

I thought I read somewhere that the issue with the 5 speed (specifically, can't say 6 speed also) was that the case couldn't take the torque. So it doesn't really matter how much you beef up the inside since the case stretching is going to happen anyhow. I'm old so my memory is not what it used to be but I swear I remember reading that on this forum.

 

I second that.

Pretty much everything I read on the 5 speed weakness issues were centering on the case distorting under load, allowing the gears to un-align themselves.
Maybe we should weld a bunch of crisscross support bar thingies on the outside.

 

I'm not an engineer so I have to ask, does all that ribbing work? I have noticed it on a bunch of OEM aluminum cases so it has to have some merit.

If anything it at least serves as some additional cooling. So maybe a cryo blanket could keep these trannys together?

FWIW, I have dealt with JOMotorsports and I have nothing but good things to say about them. I did not have to worry about putting 350hp through the tranny though.

And also FWIW, it's not HP that kills these things, it's torque. And we know how turbo's spike the torque curve.

 

If anything, it makes the whole experience a little more pleasurable.

 

For him only or for him and her?

Wait, I forgot this is a Miata site, so for him and him?

Oh and yeah it's 2020 so I have to use pronouns so, for they and them? Ahhhh, nevermind.

 

Shim and sher, thank you very much.

 

Great news, keep us posted. What is your setup, how much torque are you making, and at what RPM?

I too was under the impression that the case flexing was the weak point, but then again I couldn't see the 6 speed case being that much strong, and I bet it flexes as well. Perhaps the stronger gears just allow it to not shear teeth under flexing.

Either way, I think it would be pretty awesome to have a 5 speed 3.6 (or even 3.9) combo that would hold up to real power. The problem with a 5 speed 3.6 is that unless you are making serious power, that's way too much gear. And if you are making serious power, you are going to grenade the 5 speed anyways.

 

I literally have no idea what I'm talking about so take this with a grain of salt, but I was discussing exactly this with a fabricator on the faceplace and suggested the idea of welding on additional structure/bracing to the casing to decrease flex. He was concerned that welding could cause warpage or other issues. I'm sure yall could verify or correct that thought, but seemed valid to me.

Would be nice for someone to sacrifice a 5speed and some time welding in the name of science though

 

I know that a few years back (OK, many years), the, or one of the, fastest MX5s here had a welded ribbed case, 6-speed I think. Seemed to have made it work and handle a ton of grunt, but then later went to a Nissan box IIRC.

 

Haven't been on the forum long enough to have heard about that. I'd be very interested to see some pics if it's already been tried. I have a backup 6spd I wouldn't mind trying it on down the road.

 

Just wanted to update this thread.

Got the car tuned at 18lbs of boost. It was a remote tune so I'm not entirely to sure what the HP and torque is. However my butt dyno tells me somewhere in the 290-310hp range. Will probably run a virtual dyno later in the month and update the thread with numbers. Trans is holding up so far, shifts like butter.

If I make another post, its most likely be because the rebuilt 5 speed failed lol. Only time and abuse will tell.

 

MO POWA FO MO SCIENCE!

 

This team has lost 2x Walter built 5 speeds at 264hp after an hour or so, lost 3rd gear. Car running with trans and diff coolers.
https://www.reddit.com/r/Miata/comme...the_grid_this/