How much RWHP can a 6 speed tranny handle?
#1
How much RWHP can a 6 speed tranny handle?
I am completing my build for a road race only miata. I purchased a 6 speed (non MSM) tranny and rebuilt it. I am planning on my car having 350 to 400 RWHP and after searching around it seems like the 6 speed tranny is questionable at those power levels. Should I sell my 6 speed (while it is still good) and get a 5 speed with Quaife gears? or is that a waist of money and run the speed? Thanks
#2
Run the speed. Honestly, as far as the 6 speed, no one has a definitive number on them. 350-400 is the general consensus. I have seen one crap out as low as 280 (whp) btw. That being said, My car at 18psi handled a 5 speed. When you are at that power level, you should expect breakage. Although, I finally gave up on my saab 900 when I changed my 4th transmission in about a year an a half. God that was the worst trans set up.
#5
If you can be mechanically empathetic it can handle 400rwhpfor a while. Its really the ftlbs you need to worry about. I have 398/357. I finally blew 4th gear after 4 events My other lasted 4 also, but I didnt shred a gear,the syncros are just fugged to ****.
I am personally interested in the queef 5 speed sets myself.
I am personally interested in the queef 5 speed sets myself.
#9
Former Vendor
iTrader: (31)
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Location: Sunnyvale, CA
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AFAIK nobody's done the TKO swap yet. The basic breakdown:
Lakewood bellhousing: $650
TKO600R: $2100
resplined clutch disc & altered pilot bearing: $???
V8R framerails and crossmember: $~600
custom front diff mount: $??
custom driveshaft: ~$300-350
$4k into the car. The rest of the drivetrain will cost you $10-14k depending on your intended usage, so in the long run it isn't all that expensive - just hurts to shell it all out at once.
Lakewood bellhousing: $650
TKO600R: $2100
resplined clutch disc & altered pilot bearing: $???
V8R framerails and crossmember: $~600
custom front diff mount: $??
custom driveshaft: ~$300-350
$4k into the car. The rest of the drivetrain will cost you $10-14k depending on your intended usage, so in the long run it isn't all that expensive - just hurts to shell it all out at once.
#11
AFAIK nobody's done the TKO swap yet. The basic breakdown:
Lakewood bellhousing: $650
TKO600R: $2100
resplined clutch disc & altered pilot bearing: $???
V8R framerails and crossmember: $~600
custom front diff mount: $??
custom driveshaft: ~$300-350
$4k into the car. The rest of the drivetrain will cost you $10-14k depending on your intended usage, so in the long run it isn't all that expensive - just hurts to shell it all out at once.
Lakewood bellhousing: $650
TKO600R: $2100
resplined clutch disc & altered pilot bearing: $???
V8R framerails and crossmember: $~600
custom front diff mount: $??
custom driveshaft: ~$300-350
$4k into the car. The rest of the drivetrain will cost you $10-14k depending on your intended usage, so in the long run it isn't all that expensive - just hurts to shell it all out at once.
#12
http://www.jegs.com/i/G-Force-Transm...ductId=1343711
this with an adapter plate, maybe 3k total if someone stepped up to the plate. Could handle just as much as a TKO but for about the same without then need for a pricey bell housing or the rest of the drive line to be tampered with
this with an adapter plate, maybe 3k total if someone stepped up to the plate. Could handle just as much as a TKO but for about the same without then need for a pricey bell housing or the rest of the drive line to be tampered with
#13
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I will have new clutch discs done for my 949 twindisc, or I'll have the current discs resplined (if that's even possible). I haven't gotten that far down the road.
http://www.jegs.com/i/G-Force-Transm...ductId=1343711
this with an adapter plate, maybe 3k total if someone stepped up to the plate. Could handle just as much as a TKO but for about the same without then need for a pricey bell housing or the rest of the drive line to be tampered with
this with an adapter plate, maybe 3k total if someone stepped up to the plate. Could handle just as much as a TKO but for about the same without then need for a pricey bell housing or the rest of the drive line to be tampered with
The easy way to do this is exactly what I said above - Lakewood bellhousing, TKO600, and everything else will be custom. The TKO600R box has a crap 2nd gear (1.89) so if I actually moved forward with this I would seriously look into having a custom 2nd gear made to drop that ratio down into the 1.59-1.65 range. I want the same 3-4-5-6 split as I have now, and the TKO600R box has the right 3-4-5 ratios to make that work.
#15
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Join Date: Jun 2006
Location: Chesterfield, NJ
Posts: 6,898
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As far as gearing, I'm looking forward to the lower rpms of 5th. I'm even leaning towards the 3.42 GM rear, which will cut off 1000rpm at 75mph in 5th compared to what I have now. For the track guys who actually use/need 5th on the track, I can see that being a big issue.
The TKO600R's 2nd is too short (1.89) but 3-5 are the same as the 4-6 split in the OEM 6-speed.
I have absolutely no idea how you came to those conclusions. The G-Force box is $400 more expensive, still doesn't come with a bellhousing, and you still have to have a trans/diff mount made, respline the clutch disc(s), and have a custom driveshaft made. You cannot just have an adapter plate made, because neither Miata box came with a removable bellhousing. Unless you own a machine shop, get free materials, and value your time at $0/hr, there is absolutely no way you are putting a $2600 T5-based gearbox into a Miata for under $3k.
I decided to use the mustang bellhousing, flywheel, starter, clutch, etc because I have none of the OEM equivalents anyway on my V6 build, but that route should also work on the BP. Would it be the cheapest or best idea? Probably not. Most of us already have fancy flywheels & pressure plates that work with the miata starter. There should be a way to adapt some bellhousing to the BP pattern and having a T5 (or TKO) splined clutch disk made. Then it's a matter of correctly spacing the flywheel if it's in the wrong place with respect to the trans input shaft. I have both the miata 5 speed and T5z/mustang bellhousing in solidworks, but don't have the miata flywheel modeled. I think I gave away my old flywheels so I can't model that. The T5's pilot bearing is in the crank, not the flywheel.
The easy way to do this is exactly what I said above - Lakewood bellhousing, TKO600, and everything else will be custom. The TKO600R box has a crap 2nd gear (1.89) so if I actually moved forward with this I would seriously look into having a custom 2nd gear made to drop that ratio down into the 1.59-1.65 range. I want the same 3-4-5-6 split as I have now, and the TKO600R box has the right 3-4-5 ratios to make that work.
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