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Old 03-10-2014, 01:57 PM   #121
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It seems like the Miata 6 speed is ideal if it were only able to handle the power.

Have any of you guys that are destroying them thought of adding cooling and a trans brace to stop any case twisting? Given the challenges of fitting something else it seems worth a try. I guess at some point the torque levels are high enough to make any mods hopeless.

As a money no object solution a quafe sequential would be the real ticket.
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Old 03-10-2014, 01:59 PM   #122
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Originally Posted by k24madness View Post
It seems like the Miata 6 speed is ideal if it were only able to handle the power.

Have any of you guys that are destroying them thought of adding cooling and a trans brace to stop any case twisting? Given the challenges of fitting something else it seems worth a try. I guess at some point the torque levels are high enough to make any mods hopeless.

As a money no object solution a quafe sequential would be the real ticket.
I think a money is no object option would involve flappy paddles.
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Old 03-10-2014, 02:00 PM   #123
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Or a baller straight cut rally style sequential.
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Old 03-10-2014, 02:15 PM   #124
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Originally Posted by Leafy View Post
I think a money is no object option would involve flappy paddles.
QBE60G/QBE69G boxes are available with air-actuated paddles. ~$14k installed
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Old 03-10-2014, 02:21 PM   #125
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Originally Posted by miata2fast View Post
I don't know what all the fuss is about for the perfect transmission ratios, when in many cases a final gear change is all that is needed to get the gearing right.
*sigh*

You don't understand because you aren't a road racer, but I'll spell it out anyway. If the "low" gear (3rd in a 6-speed) is too low, like it is in both RX7 turbo options, the AR5 from a Solstice, and T5/T56 boxes, and you simply dump the rear end ratio down into the ~3.0 range to compensate for a short 2nd gear, then you end up with huge RPM drops between 2-3 and 3-4 and an extremely tall overdrive gear that never gets used. IOW, the car goes slower, period. That also ignores the fact that several of the people looking for 6-speed replacements have put $2k+ into reliable Mazda 7" rear ends and none of us are keen on ditching them just so we can switch to a CTS-V or Ford 8.8 rear end which both adds weight and takes away any hope of a decent LSD option (helical/positrac is not decent).

Read post 119 to understand why gear ratios in the transmission matter, and why no amount of screwing with the rear end ratio will fix bad trans ratios.
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Old 03-10-2014, 02:23 PM   #126
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i can have a straight cut dog box with custom ratios made for around $6k... maybe cheaper if there was a few interested.

i have checked trans temps and when mine failed at the weekend it was under 100'c...

Last edited by mr2daj; 03-11-2014 at 06:12 PM.
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Old 03-10-2014, 02:25 PM   #127
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You know there's a 5 speed jerico option as well as their 4 speed options that work with the lakewood housing. Infinite gear ratio choices. except 5th is 1:1. Which equates to dropping the coin for a speedway quickchange rear end to get a light, strong rear end with a real LSD and the correct gear ratio. But you're approaching sequential money.
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Old 03-10-2014, 02:37 PM   #128
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**** it, CVT.
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Old 03-10-2014, 05:12 PM   #129
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Quote:
Originally Posted by NiklasFalk View Post
Getrag 420G (e.g. M3 E46)
4.32, 2.54, 1.62, 1.23, 1.00, 0.83
0.00, 41%, 36%, 24%, 19%, 17%

$2k+ on ebay, plus modding. No spare parts available... New box to get syncros...

But although the M3 are running a little different powerband, just ask the racers you can get hold of. One of my firens have toasted a number of 6sp in his E36M3 and are now going to a 5sp with custom gears instead.
I don't remember the exact gearboxes he have used but there might not be a low hanging fruit in the Beemer camp either.
I have a hard-on for this tranny

BMW E39 540i 6 Speed Manual Transmission Getrag S6S 420g Use for E38 Swap D1 | eBay

$800 shipped
~100lbs
small
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Old 03-10-2014, 05:16 PM   #130
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Quote:
Originally Posted by Savington View Post
That also ignores the fact that several of the people looking for 6-speed replacements have put $2k+ into reliable Mazda 7" rear ends and none of us are keen on ditching them just so we can switch to a CTS-V or Ford 8.8 rear end which both adds weight and takes away any hope of a decent LSD option (helical/positrac is not decent).
OS Giken makes their diff for ford 8.8s now

http://on.fb.me/1ne2vwF
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Old 03-10-2014, 05:34 PM   #131
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Originally Posted by soviet View Post
OS Giken makes their diff for ford 8.8s now

http://on.fb.me/1ne2vwF

I'm so hard right now.
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Old 03-10-2014, 06:22 PM   #132
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Quote:
Originally Posted by Savington View Post
*sigh*

You don't understand because you aren't a road racer, but I'll spell it out anyway. If the "low" gear (3rd in a 6-speed) is too low, like it is in both RX7 turbo options, the AR5 from a Solstice, and T5/T56 boxes, and you simply dump the rear end ratio down into the ~3.0 range to compensate for a short 2nd gear, then you end up with huge RPM drops between 2-3 and 3-4 and an extremely tall overdrive gear that never gets used. IOW, the car goes slower, period. That also ignores the fact that several of the people looking for 6-speed replacements have put $2k+ into reliable Mazda 7" rear ends and none of us are keen on ditching them just so we can switch to a CTS-V or Ford 8.8 rear end which both adds weight and takes away any hope of a decent LSD option (helical/positrac is not decent).

Read post 119 to understand why gear ratios in the transmission matter, and why no amount of screwing with the rear end ratio will fix bad trans ratios.
I road raced in Formula Continental for 7 years, f1000 for 3. Optimizing your gears is a set of compromises and you end up with the best gear selection you can... Very important when your racing others in the same class with nearly the same car... The more unique your car is the less important absolute optimization matters. In FC we had a Hewland LD200 and would change out gears for every track. Don't and you'll lose!
In a one-off 350hp Miata it's not as important, IMHO. Durability should be the focus.
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Old 03-10-2014, 06:36 PM   #133
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3.35 1.93 1.29 1.00 0.80
0% 42% 33% 22% 20%


2.95 1.94 1.34 1.00 0.80
0% 34% 31% 25% 20%


2.95 1.94 1.34 1.00 0.73
0% 34% 31% 25% 27%


3.35 2.08 1.38 1.00 0.78
0% 38% 33% 27% 22%
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Old 03-10-2014, 07:38 PM   #134
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Originally Posted by carnut169 View Post
In a one-off 350hp Miata it's not as important, IMHO. Durability should be the focus.
No offense, but you have the experience racing a 350whp to back this up? I do, and in my educated opinion, it's extremely important.
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Old 03-10-2014, 07:46 PM   #135
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Quote:
Originally Posted by soviet View Post
I have a hard-on for this tranny

BMW E39 540i 6 Speed Manual Transmission Getrag S6S 420g Use for E38 Swap D1 | eBay

$800 shipped
~100lbs
small
5mins of google says the 540i's 6-speed (Getrag S6S 420G) was also used in the 740i and the E39 M5, which bodes well for strength for us. No parts available from Getrag, though, and they are known for breaking shift linkages.

Last edited by Savington; 03-10-2014 at 08:23 PM.
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Old 03-10-2014, 08:01 PM   #136
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Originally Posted by Savington View Post
No offense, but you have the experience racing a 350whp to back this up? I do, and in my educated opinion, it's extremely important.
No, the FB AND FC we're not even close to 350, but I'd bet a dollar I turned faster lap times than your 350hp Miata. By a lot. Won a championship or two as well. This is not a slam on you (from whom I'll be buying my motor bits unless your a jerk here ) or Miatas as I'm building one myself.

I'd agree if your being out qualified by a few seconds or chasing every last second. Otherwise you come out of a corner at 4k instead of 4200 and you drop .5 a lap. Oh well. Your still having a blast, winning the same amount of cash and fame....
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Old 03-10-2014, 08:45 PM   #137
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Quote:
Originally Posted by Savington;1110362 [B
*sigh*[/B]

You don't understand because you aren't a road racer, but I'll spell it out anyway. If the "low" gear (3rd in a 6-speed) is too low, like it is in both RX7 turbo options, the AR5 from a Solstice, and T5/T56 boxes, and you simply dump the rear end ratio down into the ~3.0 range to compensate for a short 2nd gear, then you end up with huge RPM drops between 2-3 and 3-4 and an extremely tall overdrive gear that never gets used. IOW, the car goes slower, period. That also ignores the fact that several of the people looking for 6-speed replacements have put $2k+ into reliable Mazda 7" rear ends and none of us are keen on ditching them just so we can switch to a CTS-V or Ford 8.8 rear end which both adds weight and takes away any hope of a decent LSD option (helical/positrac is not decent).

Read post 119 to understand why gear ratios in the transmission matter, and why no amount of screwing with the rear end ratio will fix bad trans ratios.
Nothing delights me more than when someone who needs the snot wiped from his nose acts like he's God's Glory.

You do not have to bring on the egotistical ****. Racing is racing. I have done enough motocross, competitive drag racing, and been around enough successful motorsports participants to know that if you are stuck with certain options that you can make changes in other areas to compensate. You seem to have this inability to grasp that simple fact. That transmission in post 119 is obviously not in the ballpark, but there are plenty of transmissions that are.

Let me spell something out to you. Lose the ego young man. The customers you have are on this and other forums you post in. The sooner you act like someone people want to do business with the more successful you will be. I will spend 30K on my bucket, and I will not spend a penny to you because of your horseshit. Take it from me, my payroll is higher than every dollar you have ever made in all jobs you have had, and in the chicken **** business you have.
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Old 03-10-2014, 08:55 PM   #138
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Originally Posted by carnut169 View Post
I'd agree if your being out qualified by a few seconds or chasing every last second. Otherwise you come out of a corner at 4k instead of 4200 and you drop .5 a lap. Oh well. Your still having a blast, winning the same amount of cash and fame....
If you look up "chasing every last second" on Wikipedia, the article redirects to my car (Theseus). The goal with that car is to develop the NA/NB chassis to its illogical limit, so if there's a way to upgrade a factory part, chances are it's been done on that car. Curb weight is sub-1900lb with a full turbo system and a windshield header. The hardtop weighs 9lbs, is made out of prepreg by aerospace geeks, can be lifted by one person with one hand without it folding in half, but will still support the weight of a 200lb driver leaning on it as he lowers himself into the car. ECU will be an AEM Infinity box. Traction control will either be through the Infinity if it works well, or through a separate Racelogic system if it doesn't. The motor in it now is a built VVT 1.9L, and it will probably get a sleeved 2-liter with a race head. Power goal is a low-boost setting in the ~375whp range with a high-boost mode as close to 500whp as possible on our investment cast manifold and an EFR7163. Trans is a Quaife close-ratio 5sp (which I'm worried about breaking) and the diff is a 3.63 OS Giken with 949Racing hi-power mods. V8R 0.500" hubs and custom axles are planned. It has XIDAs which will get lengthened and rebuilt with digressive rebound pistons and HVT tophats to match the Keisler 1.5" aluminum drop spindles on all 4 corners. 40mm widebody in front, 30mm in the rear (as narrow as possible to keep the aero footprint down), with 275/35 Hoosiers on 15x10 6ULs, and the wheels may get swapped for something custom and wider to better support the tire. About 3/4 of this is already done and in the car or on shelves in the shop.

Long story short, yes, I'm looking for every second. I don't build cars with big compromises like flawed gearing, it's just not how I work. At the end of the day, I'm just not interested in spending a ton of money on a box that makes the car slower, just like I'm not interested in spending a ton of money on a box that makes the car 40lbs heavier - those options are "good enough", and I don't work that way.

Last edited by Savington; 03-10-2014 at 09:12 PM.
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Old 03-10-2014, 09:25 PM   #139
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How important is a reverse gear to you?
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Old 03-10-2014, 09:30 PM   #140
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Originally Posted by miata2fast View Post
Nothing delights me more than when someone who needs the snot wiped from his nose acts like he's God's Glory.
I said that factually, not to be an *******. Sorry if it was taken wrong.

Quote:
Racing is racing. I have done enough motocross, competitive drag racing, and been around enough successful motorsports participants to know that if you are stuck with certain options that you can make changes in other areas to compensate. You seem to have this inability to grasp that simple fact.
In my opinion, a longer rear end ratio does not adequately compensate for having the wrong ratios. If the ratios are too far spread apart, you just go slower - end of story. Whether that speed loss comes from losing a useful gear which cripples you in slow corners, or whether you change the rear end and end up with an overdrive so tall that you can't pull it, you go slower. There's no "fix" for that, just like there's no "fix" for not having enough horsepower, not having good shocks, not having enough tire, or two dozen other things. You can still go fast, but the guy with the correct gearbox is going to be faster.
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