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Old 04-27-2010, 03:18 AM   #21
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Quote:
Originally Posted by Savington View Post
Doing what? Hardparking in the paddock? Making 900whp Mile passes? Please don't tell us, I thrive on suspense.
IDK it's Rharris's buddy. He broke down last session of the day and I didn't feel like salting the wound with a ton of questions. I think he said 5th and 6th wear gone. PM Robert
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Old 04-27-2010, 08:04 PM   #22
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Old 04-30-2010, 02:00 AM   #23
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Dang

It seems to me that the 6 speed has a much better stiffer case than the 5 but the teeth are still a bit small for high torque with track driving.

I changed my fluid and I saw no big chunks but I could definitely see that there is some seemingly heavy wear going on. Quite a bit of metal dust stuck to the drain plug for such a short time it has been in the car. I wonder if a Mazdaspeed version with the supposedly treated gears would lessen that.

Interesting that it let go on a downshift, every 5 speed I have broken has been between 4000 and 5500 rpm at full load. Car is making ~330 ft-lbs across that rpm range.

Bob
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Old 04-30-2010, 02:34 AM   #24
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Originally Posted by Savington View Post
Doing what? Hardparking in the paddock? Making 900whp Mile passes? Please don't tell us, I thrive on suspense.
We are going to tear it down next week to see what is going on. It just wouldn't go into 5th and 6th gear. It was feeling weird after lunch, but nothing too alarming.
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Old 04-30-2010, 08:38 AM   #25
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TSB- You sure were putting some interesting loads on that transmission....
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Old 04-30-2010, 10:31 AM   #26
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needs more:

I had those gears in my VW.

Anyone breaking these at 250whp?

Those ******* are loud though...I mean LOUD.
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Old 04-30-2010, 02:48 PM   #27
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Has anyone put an rx8 transmission into a miata before? I wonder what kind of power those can hold up too..

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Originally Posted by Doppelgänger View Post
TSB- You sure were putting some interesting loads on that transmission....
How so? I don't see myself doing anything out of the ordinary when i drive. In fact i think i probably treat my transmission better than savington or emilio. In terms of speed of shifting (they both shift extremely fast, much faster than myself)

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needs more:

I had those gears in my VW.

Anyone breaking these at 250whp?

Those ******* are loud though...I mean LOUD.
AND expensive as ****.
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Old 04-30-2010, 03:01 PM   #28
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What are the TII transmissions rated to? Someone really should come up with a bolt on swap for those or atleast something close to it.
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Old 04-30-2010, 03:11 PM   #29
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So all i would have to do is swap the bellhousings?
http://www.rx7club.com/showpost.php?...6&postcount=23
Full thread here:
http://www.rx7club.com/showthread.ph...76#post6374476

Gear ratio's dont seem to be too far off, i mean, i am not competing so i dont really need the "best" gear ratios. I just wanna drive the damm thing.

Miata 6-spd 99 3.760 2.269 1.645 1.257 1.000 3.909 3.295 195/50-15 913 300
Miata 6-spd 05 3.760 2.269 1.645 1.257 1.000 4.100 3.456 205/45-16 910 3145
RX-8 6-spd 03-08 3.760 2.269 1.645 1.187 1.000 4.444 3.747 225/45-18 802 3005
Source:
http://mrmazda.no-ip.com/tranchrt.txt

Special thanks to Jason for passing this info along to me.

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Last edited by thesnowboarder; 04-30-2010 at 03:27 PM.
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Old 04-30-2010, 03:25 PM   #30
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Quote:
Originally Posted by thesnowboarder View Post



How so? I don't see myself doing anything out of the ordinary when i drive. In fact i think i probably treat my transmission better than savington or emilio. In terms of speed of shifting (they both shift extremely fast, much faster than myself)


Watching the video, you get that wheel spin exiting corners, and it's not even wheels spin...you know the kind that casuses drifting. Spinning a tire under WOT and it suddenly gripping was probably pretty hard on the trans. I had similar issues when attending FM's track day and running V710s...it was unsettling when the inside wheel would spin and quickly grab traction as the weight came back on the inside. I could see/feel my shifter lurch when this would happen. A good diff that would prevent that would probably help reduce these shock loads. After the first couple of times it happened, I started lifting on the throttle to keep the wheels spin/shock to a minimum. I have only had this problem on the V710s and didn't have this problem when running some Hankook Z211s.....those just started a nice managable slide...which is probably easier on the transmission since the transition from wheelspin to grip is far smoother.

But hey, it could have been a bad transmisson, seen a hard prefious life..who knows. Just my opinion.
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Old 04-30-2010, 03:26 PM   #31
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What about the FD RX-7 6-spd from JDM land?
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Old 04-30-2010, 03:29 PM   #32
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I should just sell it all and go v8

Quote:
Originally Posted by Doppelgänger View Post
Watching the video, you get that wheel spin exiting corners, and it's not even wheels spin...you know the kind that casuses drifting. Spinning a tire under WOT and it suddenly gripping was probably pretty hard on the trans. I had similar issues when attending FM's track day and running V710s...it was unsettling when the inside wheel would spin and quickly grab traction as the weight came back on the inside. I could see/feel my shifter lurch when this would happen. A good diff that would prevent that would probably help reduce these shock loads. After the first couple of times it happened, I started lifting on the throttle to keep the wheels spin/shock to a minimum. I have only had this problem on the V710s and didn't have this problem when running some Hankook Z211s.....those just started a nice managable slide...which is probably easier on the transmission since the transition from wheelspin to grip is far smoother.

But hey, it could have been a bad transmisson, seen a hard prefious life..who knows. Just my opinion.
Good info

Quote:
Originally Posted by Doppelgänger View Post
What about the FD RX-7 6-spd from JDM land?
Need to do more research, i was under the impression quite a big of fabrication was needed to get the rx7 trans into our cars. (bellhousing adapter plate of some sort)
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Old 04-30-2010, 05:48 PM   #33
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Originally Posted by wayne_curr View Post
What are the TII transmissions rated to? Someone really should come up with a bolt on swap for those or atleast something close to it.
I have personal experience with one going about 10k of mixed street and track driving behind 400whp/380wlbtq. A few guys in the old RX7 club I belonged to put down way more than that with zero problems. I've heard that they're good to 600, but I don't have any first hand experience.
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Old 04-30-2010, 05:57 PM   #34
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Nick, how much do you flatshift the car? When I stripped it I removed the clutch switches and disabled the flatshift since I felt it was too hard on the transmission. I know you used it last year at MRLS a little bit.
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Old 04-30-2010, 06:16 PM   #35
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Originally Posted by bbundy View Post
Dang

It seems to me that the 6 speed has a much better stiffer case than the 5 but the teeth are still a bit small for high torque with track driving.

I changed my fluid and I saw no big chunks but I could definitely see that there is some seemingly heavy wear going on. Quite a bit of metal dust stuck to the drain plug for such a short time it has been in the car. I wonder if a Mazdaspeed version with the supposedly treated gears would lessen that.

Interesting that it let go on a downshift, every 5 speed I have broken has been between 4000 and 5500 rpm at full load. Car is making ~330 ft-lbs across that rpm range.

Bob
Bob, what kind of fluid are you using? Redline HD shockproof has a good reputation for keeping gears from shredding and I use it in my quaife trans. The gear whine from the gears went from a SCREAMING BANSHEE to a muffled whine, so it definitely works. I drained it when I pulled it off the old track car(MiniMe) and the particles were showing signs of degredation so it was time for fresh fluid(only 7k mostly street miles on it fwiw). Cold shifting is definitely notchy, but warmed up it is not noticeably different from the MT90 I had in there previously.

A lot of the SM guys use it in their transmissions too and most of them told me it seemed to significantly extend the life of the transmission, compared to Redline MT90 or Swepco.
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Old 04-30-2010, 06:28 PM   #36
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maybe that rx8 idea aint so hot. jason saini doesn't think much of the 04-08. i was hoping: if rx8's were same gerabox equals more crashed cars to pull from equals cheaper.

oh well, so if 06+ miata is the new hotness, ok, but whoa $7500? even for motor+6sp+driveshaft+diff, thats crazy
http://orangecounty.craigslist.org/pts/1701588950.html

i recently saw a built 430whp sr20det w/ 3071 + hardened gearbox for same money. something's not right

ref: http://www.rx8club.com/showpost.php?...2&postcount=16

Quote:
1. Venerable Miata (and 1st gen RX7) 5-speed. This box is nearly bullet proof, even in forced induction applications. Has been upgraded throughout the years, including helical reverse and dual-cone 2nd gear synchro in '94. Curiously, in '99, the retaining rings that keep the gears from 'overthrowing' were removed from the shift rods. PPF mounts from the passenger side.

2. MX-5 (2006+) 5-speed. This is a new version of the same venerable 5-speed box - exactly the same internals, and intermediate case, with a new bellhousing and tail shaft. This trans adds dual-cone synchros for 3rd and 1st, I think... it's been a while since I've been in one. This is the box that's so highly regarded by MX-5'ers, but it caused us nothing but problems when we tried to race them in the MX-5 Cup. The cases were twisting, and 3rd or 4th would regularly shear off. There was heavy evidence of the case twist. I don't think any of this would be a problem in a street application. PPF mounts from the driver's side.

3. Aisin 6-speed for '99-'05 Miata/Miata Turbo. Generally regarded as bulletproof, not raced as widespread as the RX-8 - but raced enough to know it's a good box. As noted above, has a better 4th gear ratio than in the RX-8. PPF mounts from the passenger side.

4. Aisin 6-speed for '04-'08 RX-8. Generally good reputation for street use, but very fragile for racing use. Big problems with 3rd/4th being overthrown and losing their shift-keys detent *****. Very poor metal quality for both steel and aluminum parts. Quick wear on shift hub slider teeth and matching gear teeth - causing grinding. Doesn't last very long in race use. We've made some upgraded parts that make them last better (one recently finished the NASA 25hr race,) but still a compromised design. At best, our fixes only extend the inevitable demise. PPF mounts on the driver's side.

5. '06+ MX-5 (and '09+ RX-8) 6-speed. Single case, or toploader design (much stiffer structure than the mult-part caes on the other designs.) Very large gears, much bigger than the other gearboxes. Dual cone synchros on all but 5th, 6th and Reverse. The weakest link on this gearbox is the 3/4 shift fork. It's weak metal, and breaks quite easily. We have made a billet replacement for racing use, and I hope that the new RX-8 box has an upgraded part. We've passed on everything we learn to Mazda, they are acutely aware of this issue. There is an adjustment for 3/4th shift throw, and this being mal-adjusted is the cause of most complaints from street users - the dealers can't do anything about it, because it's not in the shop manual... we've worked with Mazda, and it should be added. There are also three plastic bushings that break when the trans gets to racing temperatures. Finally, the 3/4 shift hub is prone to cracking under racing use. The gears are very durable, and the teeth on the hubs/gears stay sharp even after two seasons of racing. MOST of this gearbox is bulletproof, and Mazda is aware of the weak links... I'm sure they have integrated some of these fixes into the RX-8 version of the gearbox, knowing the weight/hp increase that it will need to hold. I can only assume that they delayed putting it into the RX-8 until they learned as much as possible about it. I would confidently say this is the best gearbox of the bunch. PPF is mounted on the [i]driver's[i] side of the case.

Sharp readers will note that on both the 5-speed and the Aisin box, in the Miata application the gearbox is trouble-free, and the RX-8 and MX-5 applications of those same boxes, they don't hold up as well. REALLY sharp readers will notice that the PPF mounts on opposite sides in each case... making me believe that's too much of a coincidence. I think the side it's mounted on makes all the difference in how the tranny will last.

Overall, I'd be happy they went to this box... it should be much better than the current one, especially for street and autox/occasional track use.

As soon as we get one here to play with (hopefully very soon,) I'll let you guys know if the improvements made it in there, and how it holds up for us on the track.

Last edited by jasonb; 04-30-2010 at 09:40 PM.
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Old 04-30-2010, 06:51 PM   #37
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Bob, what kind of fluid are you using? Redline HD shockproof has a good reputation for keeping gears from shredding and I use it in my quaife trans. The gear whine from the gears went from a SCREAMING BANSHEE to a muffled whine, so it definitely works. I drained it when I pulled it off the old track car(MiniMe) and the particles were showing signs of degredation so it was time for fresh fluid(only 7k mostly street miles on it fwiw). Cold shifting is definitely notchy, but warmed up it is not noticeably different from the MT90 I had in there previously.

A lot of the SM guys use it in their transmissions too and most of them told me it seemed to significantly extend the life of the transmission, compared to Redline MT90 or Swepco.
In my 5 speeds I had used HD shock proof. I thought the 6 speed wouldn’t like it for shifting reasons. I had Redline MT90 in it. I recently put in Amsoil 75W90 GL4 in somebody else’s 6 speed and it improved shifting dramatically so that is what I have in now. It seems to rattle less now with the fluid swap.

Bob
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Old 04-30-2010, 07:06 PM   #38
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1. Venerable Miata (and 1st gen RX7) 5-speed. This box is nearly bullet proof, even in forced induction applications.
I stopped reading there. 5-speeds bulletproof in FI applications? Hilarious.
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Old 04-30-2010, 08:17 PM   #39
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Why type of clutch is everyone running?

Bob,
When you say metal I assume you saw iron/ferrous metal and not brass, right? If you guys are using GL5 you're eating those synchros which probably means nothing for structural gear failure.
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Old 04-30-2010, 08:45 PM   #40
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Michael is using a FM level II clutch
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