Moving the Top Speed Limiter

[swathdiver]

14 minutes ago, truckguy82 said:

I’m pretty certain the limitation with driveshaft speed is all about the factory balance. I’m sure they have sloppy balance specs evident by so many people having shaking issues. If you driveshaft is on the upper limit of that spec and is out of balance your top speed will be lower. If it’s near perfect by coincidence, you should have driveshaft speed limitation of well over 300mph.

 

A perfectly balanced spinning steel tube could probably handle 100,000 rpm before the rotational g forces rip it apart.

 

Nope, it's critical speed which comes from the design specs.  Balance plays a role, but is not the deciding factor.

 

https://spicerparts.com/calculators/driveshaft-safe-operating-rpm-calculator

 

http://pstds.com/critical-speed-chart/

 

https://www.markwilliams.com/driveshaft-tech.html

 

 

[Husker_1911]

Screw it.  I'll leave the limiter, driveshaft, and entire truck alone aside from exhaust, intake, long tubes, and a tune...  and get my go-fast fix with a Gen6 Camaro SS.

[Husker_1911]

I wonder if Grumpy would approve of the above idea.  Eh, on second thought I don't care.

[Slvijoe]

I took my 2017 Silverado  W/T Reg Cab long bed out today to see where the speed limiter was set, but more so to check for any vibrations. 

Smooth as glass right to 110 and everything in between. , didn’t want to push the issue, but so much for the 100mph limiter!!!

BTW, the truck is a 5.3 4WD with 6 speed transmission, stock tires, with 3:42 gears.  

Truck felt like it had much more in it, but didn’t want to test some CHP’s radar gun. 

 

Edited September 4, 2019 by Slvijoe

[Sean D]

I have the diablo tune with speed limiter off. Iv gone to 130 MPH no problem 

[mike5511]

I just had my 2020 Sierra over 110mph 30 minutes ago. I kept waiting for it to shut off at 98 or so and it just kept climbing. Because of terrain, I let up at about 112 or so. Needless to say, I was surprised......pleasantly!

[Kef]

If you believe the critical speed calculations the limiters are set based on the driveshafts. Test drove 2 different z71s and 3 2wd trucks. First 2 did 112. Other 3 all 99. Calculate the critical speed and you’ll see in the 2wd 4 door trucks, the one piece 75” shaft will jump rope at about 110-115. I’m going to get a 2 piece because I do not trust the stock 5” .080 aluminum foil shaft.