Gearbox options/experiences
 

So we were at the dyno last week with the new turbo/engine setup and things were looking good. map was just starting to get there but still really rich and we were just about to start turning the boost up a little when BANG!! stripped 4th on the 6 speed box. had just made 373bhp and around 330fl/lb an the previous run and this run was looking a lot better with some of the fuel pulled out.

With a test day booked for a few days later and no spare 6 speed we threw a 5 speed in knowing it probably wouldn't last the day. took the first few sessions really easy just giving the car a good run down as it was the first time out this year. decided it was time to start pushing on a bit and after 16 laps of medium to hard driving it striped 3rd.

so my question is... should i just keep throwing 6 speeds at it, go down the 5 speed Quaife gear set route or something different?? i would imagine the car should be well over 400bhp after it has been back to the dyno to have the mapping finished. a 6 speed lasted all last season at 355bhp but how will it cope at 400+bhp and whatever torque it makes?

Maybe i don't know anything, but aren't the MSM 6 speeds shot peened or something? Or there is something done to them to make them stronger than a regular 6 speed.

Then again, i don't know. I thought i read that somewhere.

MSM 6 speed supposedly can take a little bit more torque than the normal 6 speed because of the shot peening. Other straight up bolt on option is the 5 speed with quaife gears.

TII tranny with the adapter plate, I like the gearing on those kind of. Need to figure out a PPF adapter.

T5z with 0.83 5th swap. Seems like decent ratios will either take the power or can be built to. BEGI is supposed to have a cast bell hosing adapter almost ready to go. Needs a shifter re-locator and some sort of PPF adapter.

Lakewood bellhousing adapter options
TKO500, 5 speed, a few gear ratio options can be built for the powah. Needs a shifter re-locator and some sort of PPF adapter.

T101a, this is the NASCAR 4 speed more or less, can be had with an assortment of ~2000 gear ratio options, easy to rebuild, can take 700hp, 4 speed and 4th is a direct drive (1:1) so it will require a ring gear in the 3.3ish range to be useable which means ford 7.5 or 8.8 rear or using a quick change rear like this one. Also needs a shifter re-locator and some sort of PPF adapter, but the shifter re-locate is super easy because its designed for it.

Jericos and other options I didnt look into as much

Texa$ or fab
Tractive sequential
Quaife sequential
etc

Did I miss anything?

What about WPC treating the 6spd? The folks over at MotoIQ rave about it.

Spend a bunch of money swapping an alternate OEM box with shitty gear ratios into the car, or $$buy$$ a Quaife 5sp with gear ratios similar to the 6-speed (i.e. good for road racing). I did the latter and don't regret it yet.

The Quaife setup isnt even Big money. Its only 2ish grand and the labor to pay someone to rebuild it. Its actually probably the cheapest option besides another 6 speed that I mentioned when you dig down into real cost.

I want a dog box, and here's where I'm going just as soon as I win the lottery:
Bogger :: Barrington Performance

Quaife. Get the short ratio 1-3, long 5. That gives you a 1st gear you can actually use.

Use a low milage NB donor and pay a good gearhead to make things fit. You will have the best shifting 5-speed in a Miata and good ratios. The Quaife kit is not bolt-in.

The only other option is forking out big dollars for a sequential box, which means bell housing, box, mounts, drive shaft, etc.

Is there even a North American dealer for Quaife that still has these in stock that will swap out the gears?

We sent him a pile of dead AZ-6's recently. They're developing a sequential conversion for the AZ-6 6 speed (90-05 Miata). Ron tells me it'll cost a lot more than a Quaife gearset for the 5 speed but a lot less than a Quaife QBE60G sequential. Anxious to see how this turns out. Most of his customers are EP and a few GT3/STL guys so it might not be optimized for big power. We'll see. The thought of sub $9k custom ratio 6spd sequential in a 350whp track Miata is..:party:

We are a Quaife dealer, and the parts are still listed on their website. I'd be happy to inquire about having a set sent over in any specific ratios, and we could build the 'box for you as well.

Jack's Transmissions

I'll stop fantasizing about the ~$20k hewland sequential boxes then for now

Win - I'll play test mule ;)

So what you're saying is that I should just suffer though only having 200 ftlbs of torque for an extra season and buy the lights out ultimate tranny. It will still have reverse right?

Btw, don't think WPC is cheap. Doing tranny internals is over $1000 for sure

I won't be selling these things if Barrington successfully develops them. Contact them to find out more.

The Barrington sequential (if it comes to light) will only hold 250lbs of tq. Not gonna be a option for the high torque turbo guys but us lowly rotrex guys are gonna love it!

And... how exactly do you know this? Just saying, if true, this sucks - out for being test mule...

I heard this from Ron at Barrington. I guess there are limits if you are using the stock case.

soo.... don't use the stock case!