Weak manual transmission, how to strengthen?

Transmission to Rear-end

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ptuomov
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Re: Weak manual transmission, how to strengthen?

Post by ptuomov » Fri Aug 31, 2018 10:54 am

On the corvette torque tube and transmission: I don’t yet know enough about rear axle and suspension geometry in general or specifically relating to this conversion to have an opinion whether the swap works easily.
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Weak manual transmission, how to strengthen?

Post by peejay » Fri Aug 31, 2018 8:38 pm

Suspension geometry should not enter into it, at least. The Corvette C5-up chassis does not use the transaxle as a suspension component. (C4 and C3 used the axleshaft as the upper control arm, like an old Jaguar, with all of the geometry problems that creates, which is a lot of why the C5 was so much a breath of fresh air)

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Re: Weak manual transmission, how to strengthen?

Post by ptuomov » Tue Sep 04, 2018 7:02 pm

Atomic Blonde soundtrack on. Thru time and space, I've got what by the West Germans' proclamations are the last two fifth gear assemblies for the G28.13. Made in West Germany in May 1987, and priced at an arm and a leg!

The next step is to break them in the most interesting way possible. Any suggestions?
AtomicBlonde.jpeg
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Weak manual transmission, how to strengthen?

Post by ptuomov » Tue Sep 04, 2018 7:09 pm

Anyone know of a reputable firm that can do cryogenic treatment and REM ISF somewhere in Southern California?
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Weak manual transmission, how to strengthen?

Post by MadBill » Tue Sep 04, 2018 11:05 pm

ptuomov wrote:
Tue Sep 04, 2018 7:02 pm
..
The next step is to break them in the most interesting way possible. Any suggestions?

AtomicBlonde.jpeg
Mount up the biggest drag radials that will fit and start practising your launch technique. =D>
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

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Re: Weak manual transmission, how to strengthen?

Post by econo racer » Wed Sep 05, 2018 5:31 am

Can you tape up a big Magnet to the bottom somewhere. Can you use Lucas Sorry for you. :(

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Re: Weak manual transmission, how to strengthen?

Post by ptuomov » Wed Sep 05, 2018 1:20 pm

econo racer wrote:
Wed Sep 05, 2018 5:31 am
Can you tape up a big Magnet to the bottom somewhere.
The drain plug has a magnet.

Anything worth seeing in this last of the Mohicans?
934CDF66-DB48-44F1-9785-B0CBFE01E022.jpeg
5BC25F73-BD6C-4A5A-988F-06B740D32C00.jpeg
DF66D974-2DC9-4035-8059-E6D65270D9C9.jpeg
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Weak manual transmission, how to strengthen?

Post by MadBill » Wed Sep 05, 2018 6:39 pm

Looks like a very high helix angle; good for quiet, not so much for strong...
Felix, qui potuit rerum cognscere causas.

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Re: Weak manual transmission, how to strengthen?

Post by RW TECH » Mon Sep 10, 2018 5:11 pm

Ken_Parkman wrote:
Wed Aug 29, 2018 5:26 pm
Completely different question - what are you doing when the failures happen?

While not a perfect solution one comment is type of clutch. You need a tremendously strong tranny to withstand shock loadings. Drag race type abuse (launch, shifts) with a hard grabbing diaphragm clutch that grips the hardest at lock is a really good way to bust stuff. Borg & Beck style pressure plates are not as harsh but I don't know how much you will gain in a street clutch if it will hold the power. And the pedal effort will get a lot worse. For real abuse a sliding clutch is way easier on the driveline and faster as well, but that is certainly not designed with street in mind.
This!!!

Take some mass (inertia) out of the clutch & flywheel (especially the disk) and consider a less agressive friction material.

I would be willing to bet that if you applied torque to the transmission input with the output locked, you would find out the transmission's ultimate strength will be 2x greater than the torque output of your engine, even if it's bunches more than the original engine for that trans.

Shock is what typically causes fracturing like you're showing in the pictures. Doesn't mean things can't be made to be more shock-resistant, but you can also reduce some of the shock force by reducing the inertia of the parts that are impacting the input shaft & gears.

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Re: Weak manual transmission, how to strengthen?

Post by peejay » Mon Sep 10, 2018 7:48 pm

With that it mind, does a dual mass flywheel exist for the engine?

Although, I think that Porsche used a weird rubber bonded clutch disk in the 944 to try to have the same effect.

DMFs are great on normal transmissions, not 100% sure what having an input shaft half the length of the car would change in this equation.

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Re: Weak manual transmission, how to strengthen?

Post by MadBill » Tue Sep 11, 2018 12:27 am

RW TECH wrote:
Mon Sep 10, 2018 5:11 pm
Ken_Parkman wrote:
Wed Aug 29, 2018 5:26 pm
Completely different question - what are you doing when the failures happen?

While not a perfect solution one comment is type of clutch. You need a tremendously strong tranny to withstand shock loadings. Drag race type abuse (launch, shifts) with a hard grabbing diaphragm clutch that grips the hardest at lock is a really good way to bust stuff. Borg & Beck style pressure plates are not as harsh but I don't know how much you will gain in a street clutch if it will hold the power. And the pedal effort will get a lot worse. For real abuse a sliding clutch is way easier on the driveline and faster as well, but that is certainly not designed with street in mind.
This!!!

Take some mass (inertia) out of the clutch & flywheel (especially the disk) and consider a less agressive friction material.

I would be willing to bet that if you applied torque to the transmission input with the output locked, you would find out the transmission's ultimate strength will be 2x greater than the torque output of your engine, even if it's bunches more than the original engine for that trans.

Shock is what typically causes fracturing like you're showing in the pictures. Doesn't mean things can't be made to be more shock-resistant, but you can also reduce some of the shock force by reducing the inertia of the parts that are impacting the input shaft & gears.
Several years back I helped a friend out with his transmission issues in a vintage Trans Am Mustang road racer. He had broken several successively higher strength input shafts. I listened to his shifts and realized the clutch was engaging late, allowing the revs to rise, then be yanked down, causing big shock loads. A quarter inch adjustment of the clutch stop was all the fix it needed.
Similarly, switching a solid to a cushion hub clutch disc can band-aid a marginal transmission.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

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Re: Weak manual transmission, how to strengthen?

Post by weedburner » Tue Sep 11, 2018 4:03 am

Consider that the inertia impact on the gears from a quick clutch engagement may only last for 0.10 sec. Doubling that engagement time can cut the intensity of that inertia impact roughly in half. If you are using the clutch to shift, a simple clutch "hit" controller can make it easy to adjust that engagement time. This effectively softens the impact to the gears from a sudden clutch engagement, without reducing the ultimate torque capacity of the clutch.

Pressure in the hydraulic throwout bearing on these graphs basically represents a reduction of clutch clamp pressure and clutch torque capacity. Here's a graph showing a hydraulic throwout bearing's Psi during an un-controlled clutch pedal release cycle...

Image

Here's a graph showing a hydraulic throwout bearing's Psi during a ClutchTamer controlled clutch pedal release cycle...

Image

T-brg Psi of the "hit" point can be changed to suit the application. This is essentially like being able to almost instantly release the clutch pedal to a certain point in it's travel. Here's a composite graph showing a range of different "hit" adjustments...

Image

The rate of throwout bearing Psi gain after the "hit" point can also be changed, this adjustment basically controls how long the clutch slips after the "hit" point...

Image

Grant

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Re: Weak manual transmission, how to strengthen?

Post by ptuomov » Wed Sep 12, 2018 4:22 pm

Thanks for the clutch info. This transmission gave up without being shifted particularly hard. In fact, it was on the fourth gear for about a month as John run various hub dyno experiments.
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Weak manual transmission, how to strengthen?

Post by ptuomov » Wed Sep 12, 2018 4:22 pm

So what does this gear damage look like, what’s the suggestion?
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Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Weak manual transmission, how to strengthen?

Post by weedburner » Wed Sep 12, 2018 7:03 pm

ptuomov wrote:
Wed Sep 12, 2018 4:22 pm
Thanks for the clutch info. This transmission gave up without being shifted particularly hard. In fact, it was on the fourth gear for about a month as John run various hub dyno experiments.
I don't know much about your transmission, but dyno experiments are often performed in a direct gear. That means power may not actually flow thru a set of transmission gears, as direct is a coupling of the input/output shafts.

Grant

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