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Axle Spline Count Strength?

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Old 09-19-2012 | 12:24 PM
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Default Axle Spline Count Strength?

How much HP/Torque can the various axle sizes take on Slicks at the track with perfect traction in an Stock Weight F-Body?

I contacted Mark Williams and they say that they have no data for the 31 Spline Axles they manufacture. I was stunned to find out that they cannot quantify any data on their axles that they are selling! I have been going back and forth with them for 3 days now on the matter! Stunned to say the least!

So what are your real life experiences with axle Strength for the various axle sizes?

28 Spline
31 Spline
33 Spline
35 Spline
40 Spline

How much can they withstand with a Axle Type (10 Bolt, 9" etc.),Type of Diff (Spool, Locker etc), Perfect Traction and 3500 pound F-Body, State Your Gear Ratio, Stall if Auto, Trans Braked etc?

I am not asking for my specific application but would like to build a data base for guys looking to build up an axle package for their own car. It would be nice to see what you guys have built and used and if you have had no problems let us know or if you had failures and had to end up upgraded what you had to something new let us know the specifics.

That way someone doesnt build something too weak or build something that is way overkill for their situation. I did a search and couldnt find specific information on Axle Strength.

Joe
Old 09-19-2012 | 12:51 PM
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Taken from brutespeed.com, hope you dont mind Bob.


Spline Count
Properly sizing your axles can be tricky. Axles too small are prone to breaking, while ones too big eat up power. Fortunately, Moser has a simple formula to help select the right axles. "First multiply your engine's torque by its First gear ratio, its ring-and-pinion ratio, and 0.90 to account for driveline loss," explains Moser. "This will give you a figure that represents the maximum amount of torque transmitted to both axles if you launched at your engine's torque peak and dead-hooked out of the hole. A 30-spline axle is rated at 6,200 lb-ft, a 31-spline at 7,000, a 33-spline at 8,200, a 35-spline at 9,600, and a 40-spline at 12,000. As long as the figure from the formula is smaller than the torque rating of the axle, you'll be in good shape. Since axles are rated individually and not as pairs, sticking with this plan will make it virtually impossible to break an axle since you'll have a safety factor of 200 percent built in."



FORMULA:

Torque at rear axles = Torque x First gear ratio x Rear gear ratio x 0.90
Old 09-19-2012 | 01:42 PM
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Originally Posted by subhumanzz
Taken from brutespeed.com, hope you dont mind Bob.


Spline Count
Properly sizing your axles can be tricky. Axles too small are prone to breaking, while ones too big eat up power. Fortunately, Moser has a simple formula to help select the right axles. "First multiply your engine's torque by its First gear ratio, its ring-and-pinion ratio, and 0.90 to account for driveline loss," explains Moser. "This will give you a figure that represents the maximum amount of torque transmitted to both axles if you launched at your engine's torque peak and dead-hooked out of the hole. A 30-spline axle is rated at 6,200 lb-ft, a 31-spline at 7,000, a 33-spline at 8,200, a 35-spline at 9,600, and a 40-spline at 12,000. As long as the figure from the formula is smaller than the torque rating of the axle, you'll be in good shape. Since axles are rated individually and not as pairs, sticking with this plan will make it virtually impossible to break an axle since you'll have a safety factor of 200 percent built in."

FORMULA:

Torque at rear axles = Torque x First gear ratio x Rear gear ratio x 0.90
This is the exact information I was trying to get from Mark Williams but they didnt have it for the 31 Spline Axles. I figure that there are variances between the different materials used (Alloys) and Heat Treating Procedures utilized so there are more variables then just one blanket figure for each Axle Size so if anyone can turn up more examples and/or post their personal examples/situations it would be great!

Joe
Old 09-19-2012 | 02:18 PM
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I've ran 33's in a Strange 12 bolt, I currently have 40's my Mark Williams 9" right now. I run a 1.76 glide with a 4.56 ratio, I'm no where close to the limit. Even when it had a BBC on nitrous leaving off the transbrake. You shouldn't be able to break the 33's if there is a spool in the rear end.

Last edited by fex77k; 09-19-2012 at 04:21 PM.
Old 09-19-2012 | 03:03 PM
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Keep in mind that the rear diff type you want to use may make a difference in what spline axles you get.

ie I don't believe you can get a posi (other than a wavetrac) for 35 spline axles.

So just make sure whatever type of rear diff you want to use comes in the spline count your going with.
Old 09-19-2012 | 03:24 PM
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Originally Posted by subhumanzz
Taken from brutespeed.com, hope you dont mind Bob.


Spline Count
Properly sizing your axles can be tricky. Axles too small are prone to breaking, while ones too big eat up power. Fortunately, Moser has a simple formula to help select the right axles. "First multiply your engine's torque by its First gear ratio, its ring-and-pinion ratio, and 0.90 to account for driveline loss," explains Moser. "This will give you a figure that represents the maximum amount of torque transmitted to both axles if you launched at your engine's torque peak and dead-hooked out of the hole. A 30-spline axle is rated at 6,200 lb-ft, a 31-spline at 7,000, a 33-spline at 8,200, a 35-spline at 9,600, and a 40-spline at 12,000. As long as the figure from the formula is smaller than the torque rating of the axle, you'll be in good shape. Since axles are rated individually and not as pairs, sticking with this plan will make it virtually impossible to break an axle since you'll have a safety factor of 200 percent built in."



FORMULA:

Torque at rear axles = Torque x First gear ratio x Rear gear ratio x 0.90


Thanks this ^^ just let me figure out if my 8.8 project with 31 spline axles and 4.10 gears is going to be able to handle both current and future LQ4/9 build.



Also here are the T56 gear ratios for any one else wanting to figure it out.

http://en.wikipedia.org/wiki/T56
Old 09-19-2012 | 06:49 PM
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Good old powerglide, lmao!
Old 09-19-2012 | 07:58 PM
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I went with Moser 35's and a spool... I was told it would be good to the 7's....so at the power level I'm at.... It's about bullet proof





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