6 speed transmission #4 go boom. - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 06-13-2014, 06:40 PM   #21
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And a Quaife box is never perfect the first time out. Be prepared for adjustments and improvements after 5-10 hours (a couple times).
Quaife/Elite are low end racing boxes...

PAR gears in the AZ6 is a different ballgame of complexity (but can be assembled less than perfect of course).
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Old 06-14-2014, 02:49 AM   #22
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Sorry Bob. I fixed the post.
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Old 06-14-2014, 04:44 AM   #23
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Is it naiive of me to think it's absurd that a solution can't be found to handle 400 whp?? It's monster power to us miata guys but it's really not that much in the bigger picture. This whole $12k to get a transmission that doesn't implode from <400 ft-lbs seems ridiculous. There has to be a solution.

-Ryan
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Old 06-14-2014, 07:21 AM   #24
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Quote:
Originally Posted by ThePass View Post
There has to be a solution.
If you don't care about ratios there are several that just need fabbing (mounts, adapters/bellhouse) to get in there.
A contributing problem is that the stock ratios are really good and if you do something why make it worse.

PAR gears seems to be the cheapest/convenient "solution", currently. But no one here knows how long it will hold (it will fail for someone for some reason at some time of course).
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Old 06-15-2014, 03:25 AM   #25
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After 3-4 6 speeds I'd have put one of those solutions in and adjusted ratio at the diff to make it work...
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Old 06-15-2014, 11:39 AM   #26
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Quote:
Originally Posted by ThePass View Post
After 3-4 6 speeds I'd have put one of those solutions in and adjusted ratio at the diff to make it work...
Gears don't work like that.
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Old 06-15-2014, 03:48 PM   #27
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two spead rear end?
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Old 06-15-2014, 09:46 PM   #28
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Is there a reason why you track guys are against 4 speed, with the quicktime bell housing and something like this

G-Force Transmissions and Long Shifters

i would think that its a far cheaper option then custom gear sets or sequential gear boxes. I find it hard to believe you can't get ratios to work with the amount of custom ratios for 4 speeds and rear ratios for our diffs.
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Old 06-15-2014, 10:31 PM   #29
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Quote:
Originally Posted by ctdrftna View Post
4-speed
That's the option I was considering before I decided to build a street car. I think a T101a with some sort of powerplant adapter might be a good option, although not for a street car.
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Old 06-15-2014, 10:55 PM   #30
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I was interested in the Richmond 5 speed road race transmission. They now make a 6 speed as well and with a fair number of ratios.
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Old 06-15-2014, 11:23 PM   #31
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I could definitely make a box with fewer gears work for either track or autocross but not both from anything I have seen. Autocross is easy you only need two gears one low gear to launch and one that will hit right around to 70Mph with an elevated rev limit.
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Old 06-15-2014, 11:52 PM   #32
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Quote:
Originally Posted by kaisersoze View Post
I was interested in the Richmond 5 speed road race transmission. They now make a 6 speed as well and with a fair number of ratios.

interesting I think you could build one with good ratios. why have I not seen that before?

http://www.richmondgear.com/pdf/RG21.pdf
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Old 06-16-2014, 01:32 AM   #33
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Quote:
Originally Posted by bbundy View Post
interesting I think you could build one with good ratios. why have I not seen that before?

http://www.richmondgear.com/pdf/RG21.pdf
That might work nicely with a 3.909.

Richmond ROD 6 speed
Gear ratio Mainshaft countershaft
Drive - 22 37
1st 3.043 38 21
2nd 1.993 32 27
3rd 1.570 28 30
4th 1.237 25 34
5th 1.000 - -
6th 0.857 26 51

looks like it might be about 50-60 lbs heavier than an AZ6 by the time you get the bellhousing and taileshaft mounting setup.
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Old 06-16-2014, 01:37 AM   #34
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Sorry to hear about your trans problems. Subed for more info.
Is the RX-7 turbo 2 trans too much fab work to mess with? Bad gearing choices?
Any potential advantages to cryo treating if your building another 6 speed?
What are you currently using for rear end and half shafts?

-Jeff
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Old 06-16-2014, 02:58 AM   #35
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Quote:
Originally Posted by 2manyhobyz View Post
Sorry to hear about your trans problems. Subed for more info.
Is the RX-7 turbo 2 trans too much fab work to mess with? Bad gearing choices?
Any potential advantages to cryo treating if your building another 6 speed?
What are you currently using for rear end and half shafts?

-Jeff
Qnce again. RX7 turbo 2 has awful freekin gearing for track use. way too big of rpm jumps in the 70-150 MPH range. I believe id loose a second or more on several tracks not being able to match shift points with track layout.

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6 speed transmission #4 go boom.-rx7tii410.png  
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Old 06-16-2014, 03:20 AM   #36
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What about 2.42, 1.53, 1.23, 1, .75?
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Old 06-16-2014, 01:05 PM   #37
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Quote:
Originally Posted by FrankL View Post
What about 2.42, 1.53, 1.23, 1, .75?
If picked right a 6 speed will have 2 useful gears for autocross and 4 useful gears for the track. A 5 or a 4 speed can be optimized for one or the other but not both. The stock gearing in the 6 speed is Ok but I think it would be improved if it were closer ratios still. Second gear needs to be slightly taller for autocross and I think slightly less rpm drop between shifts 3-4, 4-5, and 5-6 would be faster on the track. On the track you really sort of want it to where being in any of two different gears at critical points will keep you on the power curve so you can adjust shift points to match for both the track layout and speed while staying at RPM’s that have the most throttle response and power.
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Old 06-16-2014, 02:04 PM   #38
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Quote:
Originally Posted by FrankL View Post
What about 2.42, 1.53, 1.23, 1, .75?
Pretty crummy jump between 4th and 5th. still looks bad to me with a 4.10 or 3.909. Best 5 speed gearing speed seems to be the Quafe wide but even that I think can be optimized for the track or for autocross but not both with the same rear end ratio. I just get enough speed out of second with the 6 speed 3.636 combo for autocross by turning up the rev limit to 8600 rpm Im not quite sure how much taller I can go before loosing power and throttle response for slower corners cost significantly. My guess is not much like 5mph more max. I have been over geared with the 5 speed for autocross before and it was an eye opening experiance with lower gears and a higher rev limit. Top speed is not important enough to sacrafice power and throttle response on the rest of the course but shifting to 3rd sucks.


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6 speed transmission #4 go boom.-mystery-5.png  

Last edited by bbundy; 06-16-2014 at 02:21 PM.
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Old 06-16-2014, 02:20 PM   #39
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Quote:
Originally Posted by FrankL View Post
What about 2.42, 1.53, 1.23, 1, .75?
Perfect, except 5th is a little deep as Bob said.

Read this thread, especially from post ~125 onwards, for a lengthy discussion of what gear ratios are ideal and why they are ideal.

https://www.miataturbo.net/suspensio...es-dust-75506/
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Old 06-16-2014, 02:34 PM   #40
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Quote:
Originally Posted by Savington View Post
Perfect, except 5th is a little deep as Bob said.

Read this thread, especially from post ~125 onwards, for a lengthy discussion of what gear ratios are ideal and why they are ideal.

https://www.miataturbo.net/suspensio...es-dust-75506/
the 'mystery transmission' is a G-Force T5 gearset
G-Force Transmissions GFT5242-93S G-Force T5 Transmission Gears And Mainshaft Upgrade Kits - Free Shipping on All Orders @ JEGS

you can also get a 0.82 fifth gear which should work better than 0.75
G-Force Transmissions GFT82 G-Force T5 Transmission Gears And Mainshaft Upgrade Kits - Free Shipping on All Orders @ JEGS
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