Originally Posted by
farmtruc
Aluminum has a higher critical speed than steel, so an aluminum shaft will spin higher than a steel. At high speeds, strength isn't much of a concern as balance. Also, the larger the diameter, the higher the critical speed.
Gear ratio plays a large part in critical speed too. You can increase the critical speed by installing a set of numerically lower gears, say from a 4.10 to a 3.08.
Steel is stronger than aluminum, plain and simple. All N2O, hi HP manuals, transbrake equipped cars that are making lots of power, are running steel, just as I will be starting today.
The shock of the launch is what hurts the aluminum, depending on what it's made of, it may twist or snap and make a clean break (like mine).
Quick, you make us assume your truck is putting out tons of power from your post, did you get it dyno'd, I'm curious as to what it's laying down.
later,
allen