This weekend I'll be driving my 2010 Cooper with an automatic in my third autocross race and this one will be with a new 19mm sway bar set on the softest setting. I'm anticipating a bit more rotation of the rear end and seeing as how we have two near hairpin turns, I'm assuming most of my braking better come well before the turn??? I found a huge parking lot over the past weekend and set up some cones and actually practiced some slalom turns while looking at the last cone only.That was fun. Tires were squealing but the back end never broke loose. Just looking for comments and ideas. Tire pressures front and rear???? Pete
Tire pressure can be determined by marking the tires with chalk, 4 lines at 12,3,6&9 o'clock from bead to thread. Then make some runs, too much worn off sidewall pressure too low, not enough from threads too high.
There are actually little triangles on the sidewall in those positions and the "top point" is where said tire manufacture says their sidewall starts.. Ideally you scuff to that point.. So you run the same course set up each time??? Ours is different everytime out..
third autocross Yep, we run the same course and then we do the same for time only later in the day.Your club changes the layout each time? You must have a large club and a large area to work with. Sounds fun.
Ranges from 75-120 cars each month.. Locations changes each month as well but when it does duplicate a location it's a different layout and most times range from 42-58 second runs.. Of course some people are alittle faster and slower.. Shifter carts are in the mid 30's Triad Sports Car Club TSCC They usually do well each year at the Nationals. Civic in my class was 5th last year..
I have never heard of using the same course over and over. We only have 50 ish cars and we do a different course each time. How big is the lot you use? After 8-10 runs I usually can not lower my time on a given course. Anybody use one of the GPS course tracking tools? We have a guy who uses one that will tell you your hypothetical best lap if you were able to cary your highest speeds from all your laps. It is fun to see how mistakes in one section hurt you in other sections. We had a 4 cone slalom and everyperson would lose time in the next turn when they had their best slalom times. Just reinforced the need to know where to go fast and where to go a little slower to set up for the next section.
You might want to set the sway bar higher if the back of the car didn't want to come out during a slalom run. I always found that if the car was just getting loose during a slalom run it was quicker around the corners as I could get the car to rotate by trailbraking or by lift-off throttle oversteer.
On the topic of tire pressures, the chalking method works nicely as mentioned. I'd focus on getting the correct pressure in the fronts by chalking, then adjust the rear's to fine tune the handling of the car. I typically end up with rear pressures higher than fronts to get the rotation that I'm looking for (even with a 22mm rear bar full stiff and camber plates up front). Have fun! Jason
We only get 4 runs and all within 10-15 minutes of each other so you have to adapt quick.. I usually end up with close to stock pressure in the fronts 35-38 and 40-44 in the rear to help steer.. and that's not perfect as I'm not winning my class..
Sounds like a good time coming up! Chalk/white shoe-polish method works the easiest for getting pressures right. Ideal pressures will vary depending on: the tire you are running, car, mods, and ground/air tempurature. I have been running Starspecs. So, while cold, I was running 42psi up front and 36psi in the back. Usually there is a smidge of adjustment that happened after I got heat in the tires to dial in that ideal scrub point depending on the ambient temps. Good skill out there! Have fun!
3rd autocross When i said we do the same course, I meant for the day the race is run. Month to month each race is a different layout. Sorry I didn't understand the question correctly. Thanks for the info on tire pressure and if there is any more on how to set or what to expect from the new sway bar, I'd love to hear it. Pete