After some testing, here’s what I’ve found about the bump glitch and how it works
You need to have your bump setting at 8 or higher to get the most out of the glitch. Higher the number faster you can go. This is where the effect is most noticeable.
The game needs to be running at a stable 60 FPS. I have not tested at different frame rates. PC players generally have an advantage here since it’s easier to lock in consistent frame rates. Higher FPS stability seems to directly influence the glitch’s effectiveness, giving you extra grip levels when it triggers.
Some players say they can get the glitch to work every lap. Personally, I’ve only been able to get it to happen every few laps, even when driving consistently. And sometimes it will start working mid way through a lap and stop before the lap is over.
Testing with bump set to 4 or below still showed the same type of grip increase, but it’s more subtle. The benefit is there, and your lap time might still improve, but the effect isn’t as dramatic.
You need to be a very consistent/fast driver to really notice when it triggers. It’s not always obvious unless you’re hitting the same lines and inputs lap after lap.
Feel free to test this out yourself. The grip boost is real, and while it might not happen every lap, it can still give you an edge especially if you build around it properly.
I do have a tune shared the Audi #4 90 GTO if anyone wants to do further testing. It’s not the best setup for the car but you can really tell when it’s working. Drive it at hockenheimring