My wildest quess is caused by programming failure which multiplies speed without limits (i quess there is some loop that doesn't have ending method).

I found out that this works with tanks too.
Tried this with jeep, but jeep only got extremely slow.

With tanks this worked for me when i used [shift] to boost while grinding the wall. Sadly I wasn't able to control the speed.

Sorry i don't have video to proof, try it out your selves