Originally Posted by skypilot
front roll center change along with hinge pin spacing. inner toe in
Can you elaborate a bit more specifically? Are we talking about moving the hinge pins up and down, or also closer/farther from the center line of the car?
Does "inner toe in" just mean "toe in", I assume on the front? Or are you talking about using bulkhead spacers to sweep the arms?
Things I've done so far that have helped reduce traction roll:
1) Freshen the shocks. Two events ago, I found my shocks were leaking and not doing much damping, especially the left front which is the outside on all the places I was having roll issues.
2) Less sauce. After a short soak before practice, just clean the tires with sauce and wipe it off, leaving only a very thin sheen on the tire, and let it dry. No actual soak, unless the tires fall off during the run, then just a bit more for the air dry. This got rid of about 50% of my issues, and didn't seem to hurt corner speeds.
3) Less camber. Dropping from 2* front/rear to about 1.25* front and 1.5* rear got rid of about another 30-40%.
4) Corner balance the car. I found a spring that was .5mm shorter than the others. I marked it, then set the droop using blocks. Then iterated on ride height and corner balance checking several times to get things nice and even. Cross weight is now 50.3%, left/right is very close to 50%, and I'm 48% front. I think I had some wedge in the car before that was compounding issues. The car drives nice and straight on/off throttle now.
5) Much less droop. I had it before so that I could raise the chassis about 3mm before the tires lift. I reduced this to about 1-1.5mm. The car stays way flatter, and is actually much more responsive, and seemed a bit easier to drive, holding a more consistent line. This was my last change before my last main, and I'm going to revisit camber and sauce again.
6) Don't do stupid things with the steering and brakes during corner entry.
I can still roll the car, but I have to try pretty hard.
While the car is more consistent, letting me push it harder, my absolute fastest lap is still about .5 seconds off pace. My Top 20 is another half second. I can definitely work on my driving with this setup, which should be worth a lap, but I'd like to find a bit more raw speed without sacrificing the drivability.
Things I'm gonna try next:
- Check the glue on my tires.
- Go back to 2* camber and see if the roll comes back, or if lap times improve.
- Raise the inner hinge pins.