Another 6 speed bites the dust.
11-18-2013, 08:48 PM
#281
Pretty much got to use the whole gear set from the RX8 to get the assumed stronger gear. 4th is machined right on the main shaft. I think you might be able to swap the input shaft and main gear between the two to allow using a standard off the shelf Miata clutch. Miata clutch has a 15/16X 22T input and RX8 has a 1"X23T
FWIW the 4th gear in the RX8 is odd ratio spacing compared to the Miata. I think it was done entirely for strength. The Miata has a slightly better ratio with even rpm drops between 3rd, 4th, 5th shifts but little tiny fragile teeth on the 4th gears to get that ratio.
ALSO I think the strength issue of 4th gear is dramatically diminished if the car doesn’t see the track. Almost never do you get the opportunity to do a full power run through the rev range in 4th gear for any kind of sane street driving even if you typically drive like a jackass every day to work. Especially combined with super sticky DOT Slick tires whereas on a track you could do it 3 or 4 times per lap.
FWIW the 4th gear in the RX8 is odd ratio spacing compared to the Miata. I think it was done entirely for strength. The Miata has a slightly better ratio with even rpm drops between 3rd, 4th, 5th shifts but little tiny fragile teeth on the 4th gears to get that ratio.
ALSO I think the strength issue of 4th gear is dramatically diminished if the car doesn’t see the track. Almost never do you get the opportunity to do a full power run through the rev range in 4th gear for any kind of sane street driving even if you typically drive like a jackass every day to work. Especially combined with super sticky DOT Slick tires whereas on a track you could do it 3 or 4 times per lap.
what are you using? some super stiff competition mount, MSM mount, OEM?
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11-18-2013, 09:33 PM
#282
So, while you are disassembling everything, would you be willing to measure out the synchros?
There has been speculation that the s2000 carbon fiber synchro rings might be a drop in replacement. Which might lead to an even better 6 speed, (at least in shift feel and quality).
There has been speculation that the s2000 carbon fiber synchro rings might be a drop in replacement. Which might lead to an even better 6 speed, (at least in shift feel and quality).
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11-19-2013, 12:35 AM
#283
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I have AWR engine mounts the softest ones available which are absolutely brutal in a daily driver at ~3500 rpm and idle but made shifting precision so much better I decided to live with it. I will say that wheel hop on launches in first and second gear went away with removing the sprung clutch it also buzzes a lot when not loaded. Energy suspension Diff mounts. And I have also broken an aluminum Diff housing arm through the fail here notch and have since replaced it with a much beefier RX7 one.
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11-25-2013, 02:35 AM
#284
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Sorry to get off topic for a second, I just bought a 6 speed a couple weeks ago and it didn't have the 4 bolt plate that holds the shifter on. (don't even know what its called)
Anybody have a toasted 6 speed laying around that they might be able to vulture for me?
THIS is what I'm workin with. I'd be happy to provide sexual favors in return, or just money for shipping and a 6 pack if your not a REAL miata owner.
Anybody have a toasted 6 speed laying around that they might be able to vulture for me?
THIS is what I'm workin with. I'd be happy to provide sexual favors in return, or just money for shipping and a 6 pack if your not a REAL miata owner.
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11-25-2013, 11:33 AM
#285
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Sorry to get off topic for a second, I just bought a 6 speed a couple weeks ago and it didn't have the 4 bolt plate that holds the shifter on. (don't even know what its called)
Anybody have a toasted 6 speed laying around that they might be able to vulture for me?
THIS is what I'm workin with. I'd be happy to provide sexual favors in return, or just money for shipping and a 6 pack if your not a REAL miata owner.
Anybody have a toasted 6 speed laying around that they might be able to vulture for me?
THIS is what I'm workin with. I'd be happy to provide sexual favors in return, or just money for shipping and a 6 pack if your not a REAL miata owner.
Here it is new: CASE,CONTROL (Y601-17-470) - $68.83 - Y60117470 = $68.83
Although one of these guys with a busted 6 can probably provide for much cheaper. You are also going to need an complete bushing set to go with that, or possibly an upper and a tip bushing, and a shifter. What year is your 6 speed out of? Take the VIN off the side of the trans and drop it into CARFAX or something and it should be able to verify the year and reported mileage, if nothing else.
We can discuss payment options later
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11-25-2013, 05:41 PM
#286
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Yup thats what I need, thanks for the info.
Its a 2001, JM1NB353110215330 don't know how to verify miles without paying for a report but I did find the car for sale on a salvage site. It shows picture of the odo @108k. Shifter etc I should be able to transfer from a 5spd? Idk I'll do some reading to figure out what parts can swap over.
Its a 2001, JM1NB353110215330 don't know how to verify miles without paying for a report but I did find the car for sale on a salvage site. It shows picture of the odo @108k. Shifter etc I should be able to transfer from a 5spd? Idk I'll do some reading to figure out what parts can swap over.
Last edited by Golferluke; 11-25-2013 at 06:17 PM.
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11-25-2013, 07:23 PM
#289
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SHIFT LEVER KIT (PKM528-17-510A) = $119.95
Fits:
1990-2005 Miata w/5-Speed Manual Transmission
1999-2001 Miata w/6-Speed Manual Transmission (Up to 08/01/2001 Production
1990-2005 Miata w/5-Speed Manual Transmission
1999-2001 Miata w/6-Speed Manual Transmission (Up to 08/01/2001 Production
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11-28-2013, 02:23 PM
#290
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Sorry to get off topic for a second, I just bought a 6 speed a couple weeks ago and it didn't have the 4 bolt plate that holds the shifter on. (don't even know what its called)
Anybody have a toasted 6 speed laying around that they might be able to vulture for me?
THIS is what I'm workin with. I'd be happy to provide sexual favors in return, or just money for shipping and a 6 pack if your not a REAL miata owner.
Anybody have a toasted 6 speed laying around that they might be able to vulture for me?
THIS is what I'm workin with. I'd be happy to provide sexual favors in return, or just money for shipping and a 6 pack if your not a REAL miata owner.
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11-29-2013, 07:17 AM
#292
A novice like me would assume that the time spend using full torque would be the major factor for failures of this kind.
This was the reason for suggesting 3.9+ to maximize the use of 5th and 6th (but Bob is going too fast for that solution).
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11-29-2013, 08:57 AM
#293
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From the racer's ultimate top speed perspective...
For the 1:1 transmission ratio (4th in a Mazda 5 speed or 5th in a 6 speed) the input shaft and output shaft are directly coupled. No gears involved so this is the maximum efficiency & lowest transmission power loss gear. All other ratios have 2 pairs of gears involved so there is some power loss.
If you have the correct final drive (axle ratio) to use a 1:1 top gear transmission ratio, the added power (say >5%), should result in a slightly higher max speed.
Overall ratio vs. direct drive and Mazda overdrive transmissions
(See attachment - Over all ratio in top gear)
This now opens the transmission options to those with a 1:1 top gear ratio. For the high HP cars, something like the Richmond Road Race 5 speed or a T10 may work (these are wider ratio transmissions so they will not suit high RPM peaky power bands).
http://www.richmondgear.com/pdf/RG24.pdf
Lots of ratio options. Something like the following 2 gear sets may work.
(see attachment Richmond Road Race 5 sp).
Of course a transmission change such as the above will require a lots of other parts like: new bell housing, clutch, driveshaft, shifter, power frame mods, ... Weight will also be a concern as the 5 speed alone is 95lb, the T10 is a little lighter at 70 lb.
I have no experience with the Richmond Gear Road Race 5 speed transmission so I can not comment on quality or reliability. It is rated for V8 HP torque levels so 300+ HP should be no issue.
The above is of little value to the dual purpose road car...
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11-29-2013, 10:25 PM
#294
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Just read the full thread because I am going to track my miata next year again.
However, I don't have a solution as well but I have an onboard video of an auto-x miata with sequential Quaife gearbox from austria.
Enjoy and sorry for any blue *****
However, I don't have a solution as well but I have an onboard video of an auto-x miata with sequential Quaife gearbox from austria.
Enjoy and sorry for any blue *****
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11-29-2013, 11:34 PM
#295
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The 3.3 however makes some road race boxes with 1:1 finals doable. not as dual purpose as what could be done with a 6 speed but This for instance would be awesome on the track. its basically like a 6 speed 3.909 in terms of usable track gears using 2nd through 5th instead of 3rd through 6th and first gear is mid way between 1st and second. second gear would be too tall for autocross however.
Richmond 5 speed
Gear ratio Mainshaft countershaft
Drive - 27 31
1st 3.014 42 16
2nd 1.879 36 22
3rd 1.457 33 26
4th 1.188 30 29
5th 1.000 - -
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11-30-2013, 08:47 AM
#296
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The 3.3 doesn't make sense for my purposes with 6 speed boxes.
The 3.3 however makes some road race boxes with 1:1 finals doable. not as dual purpose as what could be done with a 6 speed but This for instance would be awesome on the track. its basically like a 6 speed 3.909 in terms of usable track gears using 2nd through 5th instead of 3rd through 6th and first gear is mid way between 1st and second. second gear would be too tall for autocross however.
Richmond 5 speed
Gear ratio Mainshaft countershaft
Drive - 27 31
1st 3.014 42 16
2nd 1.879 36 22
3rd 1.457 33 26
4th 1.188 30 29
5th 1.000 - -
The 3.3 however makes some road race boxes with 1:1 finals doable. not as dual purpose as what could be done with a 6 speed but This for instance would be awesome on the track. its basically like a 6 speed 3.909 in terms of usable track gears using 2nd through 5th instead of 3rd through 6th and first gear is mid way between 1st and second. second gear would be too tall for autocross however.
Richmond 5 speed
Gear ratio Mainshaft countershaft
Drive - 27 31
1st 3.014 42 16
2nd 1.879 36 22
3rd 1.457 33 26
4th 1.188 30 29
5th 1.000 - -
Another 1:1 top gear 5 speed is the "G-Force GF-5R". A straight cut dog clutch race only alternative.
If buying used, make sure you get the road race version and not the "clutch less or torsion bar" versions intended for drag racing.
https://www.gforcetransmissions.com/tran_gf5r.asp
Huge range of ratios available:
https://www.gforcetransmissions.com/pdfs/GF5r_ratio.pdf
The basic transmission is about $5-6,000 so more costly than the Richmond option.
Both of the G-Force and Richmond Gear transmissions are evolutions of an older Doug Nash Transmission design.
G-Force has many other transmission choices available. The GF-5R is likely overkill based on the HP possible from even a high boost BP.
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11-30-2013, 10:59 AM
#297
A 6sp with a stronger 4th looks to be the optimal thing to have (as we have established a couple of times in this thread), no fabbing required
3.6->3.3 is a bigger step than 3.9->3.6
The 6th would be a street only gear for those who aren't that fast (7500 shift point in this graph though).
3.6->3.3 is a bigger step than 3.9->3.6
The 6th would be a street only gear for those who aren't that fast (7500 shift point in this graph though).
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11-30-2013, 05:33 PM
#298
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Another 1:1 top gear 5 speed is the "G-Force GF-5R". A straight cut dog clutch race only alternative.
If buying used, make sure you get the road race version and not the "clutch less or torsion bar" versions intended for drag racing.
https://www.gforcetransmissions.com/tran_gf5r.asp
Huge range of ratios available:
https://www.gforcetransmissions.com/pdfs/GF5r_ratio.pdf
The basic transmission is about $5-6,000 so more costly than the Richmond option.
Both of the G-Force and Richmond Gear transmissions are evolutions of an older Doug Nash Transmission design.
G-Force has many other transmission choices available. The GF-5R is likely overkill based on the HP possible from even a high boost BP.
If buying used, make sure you get the road race version and not the "clutch less or torsion bar" versions intended for drag racing.
https://www.gforcetransmissions.com/tran_gf5r.asp
Huge range of ratios available:
https://www.gforcetransmissions.com/pdfs/GF5r_ratio.pdf
The basic transmission is about $5-6,000 so more costly than the Richmond option.
Both of the G-Force and Richmond Gear transmissions are evolutions of an older Doug Nash Transmission design.
G-Force has many other transmission choices available. The GF-5R is likely overkill based on the HP possible from even a high boost BP.
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11-30-2013, 06:37 PM
#299
From the racer's ultimate top speed perspective...
For the 1:1 transmission ratio (4th in a Mazda 5 speed or 5th in a 6 speed) the input shaft and output shaft are directly coupled. No gears involved so this is the maximum efficiency & lowest transmission power loss gear. All other ratios have 2 pairs of gears involved so there is some power loss.
For the 1:1 transmission ratio (4th in a Mazda 5 speed or 5th in a 6 speed) the input shaft and output shaft are directly coupled. No gears involved so this is the maximum efficiency & lowest transmission power loss gear. All other ratios have 2 pairs of gears involved so there is some power loss.
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