[Autocross] Points Event #3 with TSCC: June 2023
Stress testing the car with a codriver at the start of summer
Ben, a friend of mine and former MK7 owner needed a co-drive for this event so I figured it would be a good opportunity to stress test the tune, and see just how bad temps get at an autocross event under worst-case-scenario conditions.
To summarize the day: the car felt good. We settled on 35psi up front, 33psi out back (I think I could tolerate a bit higher out back, but my codriver thought it was too loose). I’m not too picky about everything being “perfect”, and as long as the car isn’t doing anything bad, I just drive.
I’m tuned by myself via Simos Tools, included the Switchpatch traction control which I had been working on and you can see it was really helping quite a bit. I still need to work on the launch control portion (likely lower boost during LC more than anything), but it works like a champ to drop 30F+ of IAT before the run starts.
If you look at the overlaid videos - at the top you’ll see “Cyl cut”, “WG pull”, and “Ign pull”. Essentially, ignition pull is used primarily for traction control purposes, the wastegate pull is utilized to ensure overboosting doesn’t happy during ignition cut, and if wheel slip exceeds a calibrated amount even with max ignition pull, it will cut cylinder(s) entirely to get wheel spin under control. You will also see cylinder cut happen on shifts for a DSG car as well, so it’s important to know when to interpret it as the traction control kicking in, vs normal cylinder drop on upshift.
I definitely drove a lot angrier than usual. I would normally consider myself a more “tidy” driver, generally speaking. The car seemed to like being driven by the scruff of the neck, unfortunately I got way behind right before the u-turn on the far end of the course but still managed fastest in STH, and 2nd in our ST* PAX class overall. I missed #1 by 0.101 to a great driver in an STR prepped NC Miata. The car was definitely capable, I just couldn’t put it all together for the win.
We got 6 runs in total, so 12 were put on the car. We had to start spraying the front tires to stay cool after my 4th run (probably should have done it after the 3rd runs). It helped marginally, but even though the “V730s love heat”… there is a limit, and back to back co-driven autocross runs on a reasonably warm day exceeds that. The bigger 255s up front (with 245s out back) seem to provide a tiny bit more grip, if not at least a bit more heat resistance before they give up the ghost vs the 245 square setup.
At this point, I had already purchased a 24x14in hood vent from Race Louvers that was at home and awaiting install, so this would be my last event in STH. Modifying the hood is not permitted in the ST* classes.
I ‘ll need to figure out what I'm going to do classing wise for auto-x. Best bet might be to just codrive other peoples' cars. Perhaps find another ST* ride for the rest of the year. Some of the most fun I had autocrossing in 2017-2018 was driving a different car at every event, but we’ll see.
