Axle Torque management

[openwheel25]

This tune and scan file is from a 2008 Silverado with a single turbo. I had it on the dyno and could not keep it from pulling the throttle back at 98 mph and 4,100 rpm. In third gear. If I kept it on the floor it will give the throttle back at 95 mph. The ETC torque management says axle when it is limiting the throttle. I did everything I know to do to get rid of this. I increased all the torque management for all the axles, increased all the limiters and cutoff I could find. Nothing would fix it. It does not do this in second gear. I am thinking there must be a table that I don't have access to. I was hoping someone on here might have run into this before and might be able to help me out. I searched the forums when I had the truck tied to the dyno but could not find any answers. Thanks for looking.10-17-20.hptdyno pull axle torque.hpl

[5FDP]

You didn't change the speed limiter source from GMLAN to calibration. It won't matter what you set the speed limiter to if you don't change that table as well.

[Jon S.]

If you survive the event, try and post a video of the Silverado driveshaft exploding on the dyno.

[openwheel25]

You didn't change the speed limiter source from GMLAN to calibration. It won't matter what you set the speed limiter to if you don't change that table as well.

Thank you for looking and helping. That is something I never knew. Why do you think it was saying axle? I would think it would say something like speed limiter or something like that. I know if you hit the rpm limit it will say engine limiter. Of course I think the 98 speed limiter was in the four wheel drive part so that may be why it says axle. This truck had the four wheel selector set to 2 wheel and only the rear wheel turning.

[openwheel25]

If you survive the event, try and post a video of the Silverado driveshaft exploding on the dyno.

Do you have experience with drive shafts exploding in Silverado's? If so what company did you use to replace the drive shaft with. Did you go back with aluminum or switch to steel or maybe even carbon fiber.

[5FDP]

The stock aluminum driveshafts are known to fail over 100mph. You could go with a built steel or aluminum driveshaft, whatever floats the customers boat. So long as it's speed rated to go that fast and there are no weird angles to the driveline it should be fine.

[openwheel25]

The stock aluminum driveshafts are known to fail over 100mph. You could go with a built steel or aluminum driveshaft, whatever floats the customers boat. So long as it's speed rated to go that fast and there are no weird angles to the driveline it should be fine.

Thanks for that. I was going to ask if the stock aluminum was stronger than the two piece steel shaft. I googled it and I only found people talking about the two piece. I will continue to use 2nd gear on the dyno and this truck has a 4l80 waiting and the driveshaft will be upgraded since it will be too long anyway.

Thanks for all your help.

[Hib Halverson]

There are two reasons for the speed limiter and both are for safety
1) tires.
2) prop shaft critical speed.

It's pretty obvious what will happen if the tire's speed rating is exceed significantly, but not to many people understand critical speed. There are videos on the Internet of testing and what happens when a prop shaft gets into a critical speed problem.

Check it out.