hf-mx5t

yup. shattered like glass just around 4500 rpm.. probably close to, or above 400tf/lb

Nagase

iTrader: (6)

Makes me want to get a gated shifter.

Without a gate cut out for fourth. Thanks for the info.

hf-mx5t

mine lasted a loong time at only 400whp. but the increase from 1.6 bar to 2 bar boost finished it off.

in for an option that will handle north of 400torques with decent ratios

bbundy

well I just stripped second gear in one too.

4th gear in 3 of them and now a second gear.

275 Hoosier A6 on 15X11 wheels grippy surface ~310 RW ft-lbs.

muoto

Third in a year.....


I guess this is my life now

TNTUBA

iTrader: (1)

Still don't get all you all trying to use stock gear boxes. I mean...I'm "just" an autocrosser and even I saw the value in doing something aftermarket.

hankclaussen

iTrader: (5)

What are you using? [edit] Nevermind, I found it. (Quaife)

codingparadox

iTrader: (2)

He and I are both using Quaife gearsets in a 5 speed.

muoto

I guess I have to look those Quaife gears at some point…

TNTUBA

iTrader: (1)

And if you do...don't skimp on having it built. Replace every single wear item in the donor box (@$650) and have a shop that knows what they are doing build it.

All of the Quaife failures I have seen had "issues" which could have been related to the install. It's not a drop in install. I've built several motors, transmissions, rear ends and was a jet engine mechanic in the US Air Force.....and I still coughed up the dough to have a pro build the box.

After you have spent 3500 in parts...what's an extra $500 to have the case machined properly and have everything set up buy someone who has built a few thousand Miata transmissions?

And before you say $4 grand....that's just too much money. Think about people who have broken 7 5 speeds and 4 6 speeds. If you assume $250 for the 5 speeds and $600 for the 6 speeds you have already spent $4,150 on stock boxes, had to change transmissions 11 times and missed at least part of an event.

Kinda ashamed I didn't do it sooner.

bbundy

If I was just doing autocross or just doing track time attack the Quafe gears would work well with the right selection of a rear end ratio for each of those uses.

Problem is a really usible ideal autocross gear is too low for even the slow corners on most every track I run.

And I also think the best SSM autocross box would be a Nascar 3 speed dog box. as a side benifit it would be about 20lbs lighter than the Mazda 5 speed I think.

Leafy

iTrader: (1)

Why not save even more weight with a 52lb Jericho 2 speed. Just gear it to 74 with the 4.10, and keep a setup 4.30 for tighter courses. Its 18lbs lighter than the 3 speed and 20 pounds lighter than the 4 speed. And I think once you put the bell housing on the 4 speed it'll be in between the weight of the miata 5 and 6s. But they're all side loader boxes which are going to have exhaust clearance problems.

Impuls

iTrader: (1)

Who is said person building all the Miata transmissions?!

codingparadox

iTrader: (2)

Dave Wheeler @ Advanced Autosports

Ryan_G

iTrader: (8)

You could also have ISC racing do it for you since they are semi local to you.

TNTUBA

iTrader: (1)

Helios did mine. While ISC is MORE than capable of building a stock box, I would not send them a Quaife set because they haven't done one before. There is some machine work which has to happen to the case...and no mention of the a chine work is in the instructions that come with the gear set. I would send it only to someone, who when you talk to them, mentions the machine work to the case BEFORE you bring it up. That way you will know they know what they are doing.

bbundy

I believe with the two speed you get a 1:1 ratio and one other gear. I think you need 2 gears below 1:1 to make it work with an avilable rear end ratio to have a 1st launch gear and a gear that will do a little over 70 at redline rpm, hence 3 speed.

Leafy

iTrader: (1)

Oh. True. I had to look at the parts diagram to notice that.

TNTUBA

iTrader: (1)

Have you all actually laid hands on that quicktime bellhousing for the BP? That thing is made out of led. My current trans is lighter than the T101A and that Bellhousing was. Just saying....Ive had both setups on the scales.

hankclaussen

iTrader: (5)

I could get on board with it, the rating and that there have been failures worry me. I would have a conniption fit if it broke after all that because then it would have made more sense to go all in on a $8k custom whatever else we're looking at.


In my case a tko600 with a .82 5th was brought to my attention and wouldn't be the worst thing in the world though there's a lot of fabrication involved compared to what I want to do (none), but zero worries about power.