Larger Billet Input Shaft

[GTRPSI]

Picked up a Quafie/Trust 6 speed dog box to use with our GTR build and i am thinking of changing the input shaft to something stronger knowing that its a weak link with drag racing.

Ive heard that the shaft sizes can be increased to Chev size and spline, we can get Jim Berry to change our clutch center to suit.

Interested to know of any recommendations for who to see for a larger/stronger billet input shaft to get made up.

Thanks in advance.

[GTSBoy]

Another thing to look at is cryo treating. I am the world's biggest sceptic with regard to cryo. Having done materials science and all that jazz at uni, I know what you have to do to make atoms move around and re-arrange themselves in metal - hence why heat treatment involves getting stuff hot. Cooling stuff down to try to achieve these effects seems counter-intuitive. The cooler you make a metal, the less mobile the atoms in the crystal structure are.

But.....business across the road from me is an automatic transmission workshop that builds a lot of autos for a lot of serious drag cars. They got sick of Ford input shafts breaking in a few cars that they deal with and did some cryo treated ones. Gone from breaking them nearly every time out on a couple of cars to "not broken one since".

Anecdotal evidence, sure. But it lines up with a lot of other similar stories. They can't all be placebo now can they?

[chez00]

PPG do a billet mainshaft with the Chevy splines, but obviously won't suit your 6 speed. Have you contacted Quaife to see what they have? We shot peen and Isotropic Superfinish (REM) components to improve fatigue resistance, and may be a good solution whether you stick with the standard shaft or get one fabricated. If you want more info on the technology have a look at our website: www.neategearboxes.com.au

[GTRPSI]

I will be sending Quaife a email this weekend to see what they say, somehow i dont think they will have it but i will try.

My thoughts on the 2 suggestions above, which have already run through my head before i posted....

Cryo treatment.

My thoughts are that any strengthening of the input shaft steel metallurgy will only make it more brittle and prone to crack more easily.

Possibly with a auto where the shock loads are less (as explained by GTSboy on autos) it may be a good thing, however i am suspicious to how well it would hold up in a 600Kw at all 4, 4WD manual application with a high clamp load clutch cover in a drag racing application with sticky rubber.

Making the metal stronger in my eyes, makes it more brittle, however my level of expertise in this area is old school self taught, happy to listen to corrections to my train of thoughts in this matter, my mind is open to suggestions (and education by those who know more).

Shot peening and stress relieving......there's something we use to do before after market rods were around.

Again, a surface depth treatment, better than standard for sure, however i dont believe it will be enough for our application.

Id be more inclined to shot peen as it improves the fatigue cracking resistance over Cryo which could produce a brittle part.

Im still thinking just getting a larger diameter billet input shaft may be the answer......just a question of where to go to get one made up.

Edited May 29, 2014 by GTRPSI

[KiwiRS4T]

Will the OS Giken unit fit your box?

[chez00]

I wouldn't consider swapping the input shaft unless it was designed for you gearbox. Tooth profiles would all vary between manufacturers and you could run into a lot of trouble if you got it wrong.

In shot peening's defence, yes it's a surface treatment. So is pretty much any other process we use to make metal stronger and more fatigue resistant. That's because the vast majority of crack formation occurs on the surface. Pretty much every aerospace component is shot peened for this reason and is testament to the process's effectiveness. I'd be surprised if Quaife didn't shot peen gears anyway to be honest.

The REM process can be done to the entire gear set to reduce friction, reduce heat in the oil and so on. If you have a look on the remchem website there are a bunch of SAE papers proving the effectiveness of the process. There are some "stress relieving" characteristics as a result of the process too. A large spline option would be best though.

[GTRPSI]

Will the OS Giken unit fit your box?

No idea of the OS tooth profile and gear diameter compared to the Quaife one.

I wouldn't consider swapping the input shaft unless it was designed for you gearbox. Tooth profiles would all vary between manufacturers and you could run into a lot of trouble if you got it wrong.

In shot peening's defence, yes it's a surface treatment. So is pretty much any other process we use to make metal stronger and more fatigue resistant. That's because the vast majority of crack formation occurs on the surface. Pretty much every aerospace component is shot peened for this reason and is testament to the process's effectiveness. I'd be surprised if Quaife didn't shot peen gears anyway to be honest.

The REM process can be done to the entire gear set to reduce friction, reduce heat in the oil and so on. If you have a look on the remchem website there are a bunch of SAE papers proving the effectiveness of the process. There are some "stress relieving" characteristics as a result of the process too. A large spline option would be best though.

At the end of the day i may send it off for shot peening, i might ask Quaife if its already been done to it before i pull it out, good suggestion that it may have already been treated, that didn't cross my mind.

I have sent them a email asking if they make a larger input shaft, just waiting for a answer.

I spent last night researching getting a larger shaft made up, i noticed PPG mentioned they can custom make parts, will see how i go with Quaife first, then contact PPG about sending my sample to them and getting the shaft replicated to suit the Quaife gears in their larger input chev truck shaft size, hopefully they might be able to do it.

Edited May 30, 2014 by GTRPSI

[XRATED]

I chose to leave my input shaft stock size as a bit of a safety measure. If your shockloading the drive train hard enough to break an input shaft, then your putting alot of pressure onto everything down stream. Your also shockloading the tyres...

I figured I would rather an input shaft go than start stripping gears in my ppg gearset, pulling bearings apart, twisting centre plates, body,mounts etc... I also choose to run stock input shafts in the rear for similar reasons.

...saying that, I'm not running 600rwkw yet, but I do use street drag tyres, unsprung multiplate clutch and nitrous.

I guess what I'm trying to say is choose you 'weak link'..... and plenty of very fast GTR's have been racing for alot of years with stock size input shafts.

If your looking for ultimate? then yeah go bigger, but if you go to that extent, I'd be looking at soild mounting almost everything, look at the rear geometry carefully, billet axles/half shafts (they still break) with larger Cv's.....so on and so forth.

..anyway, that's where I got with it.

Cheers

Justin