6 speed transmission #4 go boom. - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 06-16-2014, 02:35 PM   #41
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Old 06-16-2014, 02:40 PM   #42
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That box can also be had with 2.94, 1.94, 1.34, 1.00, .82 which I really like, lets me keep the 4.10.
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Old 06-16-2014, 02:47 PM   #43
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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/
for comparison.



Also for discussion Last night I peced together a gearset in that Richmond 6 speed. It can be made very close to what can be found in the NISMO AZ6 or it can also be made very close to the stock Miata 6 speed with a taller 1st and 2nd. first time I seen anything like that that you can get the gearing right in. cost about $3700 from summit for the box. I think you can buy the bellhousing to fit it to a BP from summit as well.
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Old 06-16-2014, 04:17 PM   #44
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Quote:
Originally Posted by bbundy View Post
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.


I keep forgetting that we're always talking about BPs specifically. I look at the TII gearing and say "that's not too shabby."
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Old 06-16-2014, 06:27 PM   #45
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Quote:
Originally Posted by Leafy View Post
That box can also be had with 2.94, 1.94, 1.34, 1.00, .82 which I really like, lets me keep the 4.10.
if you are using primarily for autocross in SSM I think you would want the 5.125 rear end with those gear ratios. selecting a second gear that is usable on the track for slow turns on the track means its way too tall for autocross unless your car has awsome power and throttle response starting at 3000 rpm or the speed range on your autocross course is between about 50 and 95 mph.

I think those ratios would work quite nicely for a high power track car.
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Old 06-16-2014, 06:34 PM   #46
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1.94 2nd gear with the 4.10 and 275s is like a 71mph top speed with 8500rpms. I might consider the 3.9 with it.
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Old 06-16-2014, 06:46 PM   #47
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Quote:
Originally Posted by Leafy View Post
1.94 2nd gear with the 4.10 and 275s is like a 71mph top speed with 8500rpms. I might consider the 3.9 with it.
Oh my bad I still had the 1.53 second in my spreadsheet. you would have a decent autocross box and just 3 gears for track use though.

Last edited by bbundy; 06-16-2014 at 06:58 PM.
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Old 06-16-2014, 07:12 PM   #48
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Which takes us back to needing a 6 speed to have a good auto-x box and a good RR box. Like the Richmond Gear 6 speed with the 1.125 x 26 spline input shaft

2.77, 1.88, (1.67, 1.52, 1.46, or 1.36), 1.19, 1.0, 0.84

This is like a $3900 tranny, dry weight of 108lbs. So its a weight gainer compared to our 6 speed but you'll never have to think about it again. A a bonus, the fitment we want is the C4 vette which also has a pickup for a torque arm that was should be able to make a ppf adapter for.
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Old 06-16-2014, 07:48 PM   #49
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Quote:
Originally Posted by Leafy View Post
Which takes us back to needing a 6 speed to have a good auto-x box and a good RR box. Like the Richmond Gear 6 speed with the 1.125 x 26 spline input shaft

2.77, 1.88, (1.67, 1.52, 1.46, or 1.36), 1.19, 1.0, 0.84

This is like a $3900 tranny, dry weight of 108lbs. So its a weight gainer compared to our 6 speed but you'll never have to think about it again. A a bonus, the fitment we want is the C4 vette which also has a pickup for a torque arm that was should be able to make a ppf adapter for.
yea if I was going to do an autocross only box I would go 2 or 3 speed I think.
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Old 07-09-2014, 02:48 PM   #50
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Subscribed to this one too.
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Old 07-10-2014, 03:47 PM   #51
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Quote:
Originally Posted by Leafy View Post
That box can also be had with 2.94, 1.94, 1.34, 1.00, .82 which I really like, lets me keep the 4.10.
Those are the standard T5z ratios on 1-4, and a ~$200 5th gear option. Changing 5th does not require disassembling the main transmission body, just removal of the tailshaft piece. T5z is a very affordable transmission and strong enough for anyone on this site.

Quote:
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1.94 2nd gear with the 4.10 and 275s is like a 71mph top speed with 8500rpms. I might consider the 3.9 with it.
I'm running it with my 3.90. I'm not a track guy but it's nice on the street. The standard .63 5th is a HUGE drop in rpm. I'm at ~2700rpm at 75mph, which is nice but the .8x 5th is on my to-do list.
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Old 07-10-2014, 03:50 PM   #52
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Tim, is the T5z supposed to be stronger than the T5WC? The T5WC would break around the same torque as the 6 speed.
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Old 07-10-2014, 04:04 PM   #53
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T-5z is the world class trans. Technically a 330ft-lb capacity in a heavy mustang doing dragstrip yank the wheels launches with dragradials.

I know of racers running significantly more than 330ftlbs thru them on the strip.

But yeah maybe, apples/oranges application. Maybe the extra heat from road racing will cause damage in similar time to the 6 speed. That would suck.
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Old 07-10-2014, 04:08 PM   #54
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Quote:
Originally Posted by TurboTim View Post
T-5z is the world class trans. Technically a 330ft-lb capacity in a heavy mustang doing dragstrip yank the wheels launches with dragradials.

I know of racers running significantly more than 330ftlbs thru them on the strip.

But yeah maybe, apples/oranges application. Maybe the extra heat from road racing will cause damage in similar time to the 6 speed. That would suck.
I guess. I thought fox bodies could still lunch the world class tranny in stockish form on early 90's era street tires though, they just did it less often than the older fox bodies that came with the non-wc t5.
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Old 07-10-2014, 10:39 PM   #55
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I keep thinking about BP to T5 adapter.
Here are my thoughts:
- Most common Ford T5 has 17mm tip of input shaft. Miata pilot bearing is 35mm OD. Fastenal has a bearing just that size
- T5 pilot bearing (at least on Ford transmissions) goes into the block while Miata pilot bearing goes into the flywheel. This gives enough offset for an adapter plate that would sit between stock T5 bellhousing and BP block.

Ideally, the adapter plate would sit between miata bellhousing and T5 because it has a simple, easy, 4 bolt flange. But miata transmissions don't have separate housings, the whole front part is one piece.

BUT!
There are also automatic miatas, right?


90 93 Mazda Miata Automatic Transmission | eBay

This is a 90-93 automatic transmission and it appears to have a very nice, separate bellhousing. Now, its an auto so there is no provision for a clutch fork. But thats a much, much simpler problem than not having a bellhousing, imo.
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Old 07-10-2014, 10:45 PM   #56
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Further research shows that only NA automatic transmissions have that bellhousing, the NB transmissions are different.
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Old 07-11-2014, 12:34 AM   #57
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Maybe lakewood can be re-drilled for the T5 to mount to it.
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Old 07-11-2014, 12:42 AM   #58
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Lakewood bellhousing is 20lbs and $700, **** that ****.

also
MX-5 Miata Forum - View Single Post - A question regarding interest


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Old 07-11-2014, 09:16 AM   #59
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I am also looking into this and have one of the T5 rebuilders commenting yesterday
"I was able to confirm that the Quicktime RM4097 bell housing will bolt
to the 88-92 Camaro T-5 case and would expect to have the Camaro size
input shaft! "
Yes it is $600-700 for the bellhousing and it will be steel, but it is readily available and claims that it does not require further fabrication.
G-force has apparently stopped producing dog ring gear sets for T-5, too many issues with people wearing them out and asking for warranty rebuilds.
Looking for other vendors providing straight cut dog ring gearsets for T-5...
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Old 07-11-2014, 10:46 AM   #60
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Are you looking for straight cut gears or dog ring? I don't know if g-force ever had a straight cut gear set... they only show helical dog ring and helical synchronized. No straight cut gears...

You can get a faceplated TKO600 from Liberty's Gears. It should also bolt up to the Lakewood housing. They could faceplate any other transmission, e.g. T5 or whatever. New Page 1

As far as I understand, faceplated and dog ring is more or less the same thing.


edit: google shows that g-force did have straight cut gears circa 2008 (?)
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