On the Torque(Torque is the killer, not HP) side, its got a ton of of variables. Stickiness of the tires, Launch Load, Engine Torque etc. etc. We've seen failures in the Pinion Gear from Launching, 2nd and 3rd from repeated over torque, and repeated synchro death.
I am really fortunate that not only do we have a proven high performance/racing gear and shaft partner, but we also have 3 different material & engineering experts consulting!
- Combined 80+ years in materials science, specifically high strength steel design and use in motorsport, aerospace, and OEM gear, shaft, and axle applications.
We're upgrading to improve all these areas:
Most important is design:
-Wider 1st, 3rd, 4th to add strength
-Improved fillets in key areas to reduce stress risers
-Bigger, thicker gear roots to vastly strengthen teeth
-Lower Helical angle to improve strength.
-Closer ratios to reduce the work on the synchros for longer life
-Better material and heat-treatment.
Stock uses a softer, case hardened steel. They do this because it is easy and cheap to machine and the case hardening gives about 0.040" of hard outer layer for wear and tear.
We'll be using 4340 THROUGH-Hardened steel for everything but the input shaft. This provides a far tougher, more flexible part:
The input shaft will be 300M. 300M is "super 4340" and damn-expensive. It has even higher toughness, ductility, and greater surface hardness and crack resistance. This part will also be cryoed as standard.
Above and beyond this, for even more extreme duty, we have a proper Aerospace grade shot-peen partner(they shot-peen Apache rotors(GunPilot giving you the shout-out!)) AND the correct SAE spec for media and intensity to add significant compressive pre-stress for even higher durability. Not some guy blasting parts randomly in a booth in his garage. Each lot has a pair of SAE standard test strips to show the peening intensity. This will be an option since it is not cheap.