reducing t56 weight
reducing t56 weight Has anyone left out unneeded gears/synchros, etc to reduce weight and MOI in a t56? On the track, I'm in 3/4/5 all the time with short enough rear gears and I was thinking someone crazy might have gutted a t56 already and would be interested in how much weight was reduced and if there were any balance issues with leaving stuff out. The car weighs 2200 lbs so getting going from a stop in 3rd gear is doable. Getting stuck in a sand trap or on an incline might be a problem, though. Putting a winch on the trailer might also be necessary. The gears are heavy. The sliders are also not light. Could even machine the countershaft, although, might not be a lot to save there. 6th would need a stop/retainer so the synchro doesn't fall apart. It also has the added bonus of never being able to shift into 1st or 2nd by accident. 
Or maybe this is a bad idea...
Or maybe this is a bad idea... What vehicle? From the sounds of it, you'd be better off going with a T5 or TKO.
Removing synchros can be done, ask for faceplating the T56. That is usually done to improve reliability if your setup destroys the synchros and gears.
Removing synchros can be done, ask for faceplating the T56. That is usually done to improve reliability if your setup destroys the synchros and gears.
Miata. Makes about 450 whp. I've seen t5s used in ls1 swapped miatas and would rather stick with the t56. The t5 swap kit wasn't exactly bolt-in. Faceplating may improve shifting with gears I want to keep, but what about the gears I don't need? Was hoping someone already tried removing gears to see how well it works to reduce weight and MOI. I have a t56 in pieces right now so maybe I'll just weigh some of the gears, but that won't tell me how the reduction in MOI improves shifting.
I really dont see it helpng much. The gears are very close to the shaft and the gears on the countershaft cannot be removed since they are all case in a line. Also the synchro rings are very light. With the realtively small weight savings and radius of the gear relative to the center of the shaft the moment is not large at all. youre better off investing in the lightest smallest dia clutch setup to reduce moi.
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Joined: Sep 2014
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From: Merica
You can drill the gears and shafts for lightening but its costly and doubtful that much is gained from it. Its common practice in circle track classes that require certain transmissions. Every ounce reduced for them counts in super tightly regulated classes.
As redbird stated, I don't think gearbox internals are the best place to cut weight.
With your power to weight I suggest: carbon clutch, lightweight flywheel, carbon driveshaft, and lightweight crank pulley.
Can you easily drop in a 4spd Muncie? IIRC they have long gears, survive big power, and 4th is 1.00 ratio for highway.
With your power to weight I suggest: carbon clutch, lightweight flywheel, carbon driveshaft, and lightweight crank pulley.
Can you easily drop in a 4spd Muncie? IIRC they have long gears, survive big power, and 4th is 1.00 ratio for highway.
The clutch, flywheel, driveshaft, and damper on the car are already lightweight and have relatively low MOI. Not much I can do there. The ratios on a muncie would not be ideal for road racing and 450 whp is already way more power than the car needs on the track to have fun so handling more power isn't needed.
Drilling gears is interesting but probably way outside my budget. I'd rather just remove the unneeded ones entirely. Sounds like no one has tried this, though. I think I'll start weighing the t56 parts I have - wonder what contributes the most weight. The main and counter shaft are pretty beefy but so are the gears.
Drilling gears is interesting but probably way outside my budget. I'd rather just remove the unneeded ones entirely. Sounds like no one has tried this, though. I think I'll start weighing the t56 parts I have - wonder what contributes the most weight. The main and counter shaft are pretty beefy but so are the gears.
Last edited by orion4096; Jan 6, 2015 at 11:30 AM.
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Pick up a used 4 speed from a NASCAR team. Light as hell, strong, better shifting (no synchros). They are all based off a T-10 so they are pretty compact. That's my plan in the future. If you figure out how to get rid of gears in the 6 speed, a winch for the trailer is a must. No way you can get a car on a trailer in 3rd without murdering the clutch, 2200 lbs or not.
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