Ask Tim Zimmer of tmzperformance.com (or Twicks69 on here). He's extremely knowledgeable and honest.

Don't waste your time on Mitsubishi gears with that level of torque. The next step up would be the PAR synchro gear set, and/or the NEAT gear set if it ever gets released. Nobody really knows for sure how much more power the NEAT kit is good for, but it's still helical gear (quiet) and replacement parts should be easiest to obtain.

More torque usually means more clutch to handle the extra torque. More clutch generally translates to the clutch grabbing harder during engagement.

Look into adding a 'tamer to the clutch pedal, which effectively reduces the peak impact on the geartrain as the clutch engages.

Grant
clutchtamer.com

I don't know much but I have heard of people taking a stock F5M33 and sending the gear set off to be cryoed to mimic an evo 3 gear set. I'm not sure how much HP/torque it would be capable of though.

Personally, I think the best option will be the one that is in the process of being designed and manufactured by NEAT Gearbox in Australia, which will be a stronger gearset with better material being used, along with keeping a helical gear design and synchronized. Their gear kit is replacing all of the weak points, along with all of the obsolete parts from Mitsu, and should be a fairly comprehensive kit once it is completed.

You can find more information regarding it here - https://www.dsmtuners.com/threads/group-buy-stronger-5-speed-gears.545357/

tschuhly said:

I don't know much but I have heard of people taking a stock F5M33 and sending the gear set off to be cryoed to mimic an evo 3 gear set. I'm not sure how much HP/torque it would be capable of though.

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The amount of engine HP/torque is typically not what causes manual transmission gear failures, as the clutch's engagement rate is what actually determines the peak impact sent to the gear teeth.

Here's a link to a page to help explain the concept of inertia management...
https://clutchtamer.com/clutchtameruniversity/

Grant

Oh, I beg to differ. Torque IS what will take all the teeth off of a gear. I also build 400 SBC stuff (it has ALOT of torque). I KNOW that the rear dif in this car is not up to taking it. Its not if, its WHEN it will no longer put up with the abuse and this is in an auto car, around 3800lbs. I am fully prepared for it to tear up the new set of 3.73 gears I put in it less than 1000 miles ago. Just my 2 cents. Take it or leave it.

Agreed, I've sheered all the teeth off of 3rd just rolling into it, zero shock on the gear.

jdxnc said:

Agreed, I've sheered all the teeth off of 3rd just rolling into it, zero shock on the gear.

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Something ive never been able to investigate, did yiu ever check preload AFTER a failure?
Unless they're really fresh ive always found preload to be sloppy and there is clear evidence of the race spinning in the bearing plate. Ive also notice the bearing plate flexes rather easily. Curious how bad it is once you up the power alot on an involute gear set. There is a reason Boostin makes a billet plate. I assume this is it.
Ive never been at gear shearing power levels but I can see if gears are allowed to move away from each other....boom.

pauleyman said:

Something ive never been able to investigate, did yiu ever check preload AFTER a failure?
Unless they're really fresh ive always found preload to be sloppy and there is clear evidence of the race spinning in the bearing plate. Ive also notice the bearing plate flexes rather easily. Curious how bad it is once you up the power alot on an involute gear set. There is a reason Boostin makes a billet plate. I assume this is it.
Ive never been at gear shearing power levels but I can see if gears are allowed to move away from each other....boom.

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When it's happened to me, it's been after several hard pulls....so yeah, I'm sure it got sloppy from case expansion. Last one before going to a dogbox wasn't possible to measure This is exactly what the Boostin plate prevents.

jdxnc said:

When it's happened to me, it's been after several hard pulls....so yeah, I'm sure it got sloppy from case expansion. Last one before going to a dogbox wasn't possible to measure This is exactly what the Boostin plate prevents.

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Makes me very curious on "lower" hp cars. Ive long thought about that boostin plate even on a sub 400 car.

jdxnc said:

Agreed, I've sheered all the teeth off of 3rd just rolling into it, zero shock on the gear.

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You remember the tq you were at when you did this?

Im on the fence about turning it up more but my car kinda feels slow again

-Daniel

99dsmer4g63 said:

You remember the tq you were at when you did this?

Im on the fence about turning it up more but my car kinda feels slow again

-Daniel

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I think the stock transmissions are only good for like 450hp

tschuhly said:

I think the stock transmissions are only good for like 450hp

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Transmission longevity depends more on torque, not hp. And since Mitsubishi only rated our transmissions for 243 lb-ft of torque, well, small wonder why they fail. I really don’t understand why so many people want massive numbers knowing the costs. Keep it light & punchy and enjoy.

Canadian_CD9A said:

Transmission longevity depends more on torque, not hp. And since Mitsubishi only rated our transmissions for 243 lb-ft of torque, well, small wonder why they fail. I really don’t understand why so many people want massive numbers knowing the costs. Keep it light & punchy and enjoy.

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Do you know what the evo3 transmissions with the hardened gears is rated for?

tschuhly said:

Do you know what the evo3 transmissions with the hardened gears is rated for?

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The same. The last two digits of the transmission classification (W5M33) refer to the torque rating in nm (x10). The Evo 4+ is W5M51. The major upgrade with the later transmission was the input shaft, which may have been the reason for the higher rating. The Evo 2/3 gears aren’t miracle workers, and aren’t even as strong as some of the DSM gears of the same era. It’s all a question of fatigue over time with these. Yeah you can run past the torque rating of the transmission, but how much past, and how often you use that torque, are major variables on how long the gears will survive.

1990TSIAWDTALON said:

Oh, I beg to differ. Torque IS what will take all the teeth off of a gear. I also build 400 SBC stuff (it has ALOT of torque). I KNOW that the rear dif in this car is not up to taking it. Its not if, its WHEN it will no longer put up with the abuse and this is in an auto car, around 3800lbs. I am fully prepared for it to tear up the new set of 3.73 gears I put in it less than 1000 miles ago. Just my 2 cents. Take it or leave it.

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The clutch draws more torque than the engine puts out.

Grant

99dsmer4g63 said:

You remember the tq you were at when you did this?

Im on the fence about turning it up more but my car kinda feels slow again

-Daniel

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whatever it took to run a 10.47 @ 137

clutchtamer said:

The clutch draws more torque than the engine puts out.

Grant

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Not my car. Torque certainly is the end for any set of gears/axles/ujoints etc.

1990TSIAWDTALON said:

Not my car. Torque certainly is the end for any set of gears/axles/ujoints etc.

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What kind of car/engine/trans do you have?

Here's a graph showing calculated torque applied to an input shaft during an actual stick shift drag run. The engine itself only puts out 425ftlbs on it's own, but notice how torque applied to the transmission's input shaft spikes up while the clutch is pulling the engine down against WOT. That spike is the result of the clutch pulling inertia out of the engine's rotating assy...


Grant

Well its not really new stuff. I built my 1st trans in 1979, a Muncie 4 speed. The clutch should take a load off of torque initially on any stick car. When the MOTOR makes its torque DURING the pull is when gear teeth seem to say "NO".

I really appreciate all of the replies! I am reading through all of them. You guys are great. Im glad to have the abundance of information!

jdxnc said:

Agreed, I've sheered all the teeth off of 3rd just rolling into it, zero shock on the gear.

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Heard that

1990TSIAWDTALON said:

Well its not really new stuff. I built my 1st trans in 1979, a Muncie 4 speed. The clutch should take a load off of torque initially on any stick car. When the MOTOR makes its torque DURING the pull is when gear teeth seem to say "NO".

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The clutch doesn't "take the load off torque on any stick car". The clutch actually INCREASES torque applied to the input shaft while the clutch is slipping against wide open throttle. That's because the clutch is drawing additional inertia torque from the engine's rotating assy while it is slipping, which in-turn causes the engine to lose rpm against WOT. The quicker the clutch pulls the engine down, the higher the resulting inertia torque spike will be.

The reverse is also true. Any time an engine is gaining rpm, it's rotating assy is absorbing some of its torque, which in-turn REDUCES the amount of torque that actually gets applied to the transmission's input shaft.

Note that the 425ftlb engine in the graph I posted earlier doesn't actually apply 425ftlbs to the input shaft at any point during the run. That's because it is either gaining or losing rpm against wide open throttle everywhere on the graph, which means the engine's rotating assy is also either absorbing torque or releasing torque everywhere on the graph. The engine never runs at a steady rpm where it would actually apply 425ftlbs to the input shaft. At every point after the clutch is "locked up" and not slipping, that 425ftlb engine is putting out LESS than it's 425ftlb potential. In 1st gear during the "pull", that 425ftlb engine is only applying 204ftlbs to the input shaft. In 4th gear during the pull, torque to the input shaft is up to only 403ftlbs.

Grant