Project Update for April 27, 2012 - Part 2: So the update above covered last week's preparation and this update will cover the ProSolo event. We bombed out to the 2012 SCCA ProSolo which was being held at a "local" site on Friday morning - Mineral Wells, TX, only 2 hours away. We arrived at 1 pm so we could help with registration or whatever else the event co-chairmen (Brad and Jen Maxcy) needed. Since we were a sponsor to the Texas Region SCCA for this event (we put up $ for Friday night's welcome party), we got to set-up our trailer and vendor table near the Lincoln Welcome Center trailer/Tech line and next to the giant "shade tent" that was being set-up late Friday. Only had to move our trailer 3 times to make room for everything there, heh. Weather was PERFECT after a brief rain shower Friday at noon, with temps in the 60s-70s all weekend and sunny skies.
Once we got the Mustang unloaded, Amy went to work getting people to sign waivers at the front gate while I got the car prepared for tech. Several sponsor decals later the car passed tech and I got in line for practice starts on the tree. A ProSolo is an unusual autocross format where there are two mirror image courses run simultaneously with a drag race style "Christmas tree" start. You reaction time at the tree
does factor into your course times, so "cutting a good light" is critical. The slower your reaction time, the slower your lap time is because the timer starts as soon as the light goes green, not when you cross the start beam like in most autocross events. It's not uncommon to lose 1 or more tenths of a second at the tree, so you strive to cut perfect .500 lights (or at least lights in the .5xx-.6xx range).
I took four practice starts on the new tires and had some pretty blah 60 foot times (2.2-2.4 sec) and reaction times all over the place, but I had one .510 light (a .500 is perfect, but anything .499 or quicker is a red light and you get no time... kind of like a DNF). This was after lowering tire pressures a good bit. Since our car was the only one at the event (160 entrants) on Kumho R compounds, I didn't have much good intel on proper tire pressures to run. I had raced on V710s in the past and remembered that after testing we ran pressures really low... like sub 30 psi, down to 25 even. ESP guru Mark Madderash agreed and said he remembered pressures being that low on this tire, but not many people have run them competitively in Solo in 5+ years.
Vorshlag ProSolo Picture and Video Gallery: http://vorshlag.smugmug.com/Racing-E...roSolo-042012/
Practice time was running out so I went and grabbed Amy so she could take some practice starts, while we continued to play with tire pressures. She was having a helluva time with the tree and kept red lighting, so I bought her more tickets. After 10 practice starts she had the tree down and was popping off some mid-.5xx lights (she has cut perfect .500 lights at Pros before), but still struggling with sixty foot times (2.4-2.8 sec). We talked through the launch, which was quickest for me at 1800 rpm. I guess I have a slight advantage over her with literally thousands of dragstrip starts on R compound and street tires (a bunch of us used to drag race our street/autocross Mustangs in college, using our autocross tires). So I can't give her too much grief for that. I wasn't exactly setting record sixty foot times myself (my best all weekend was only a 2.20 - the best in ESP was a 2.0 seconds and Madderash cut 2.1-2.2).
Friday night we stayed out at the event site late, grilling burgers and hot dogs for 100+ hungry racers for the Welcome Party. I manned the grill for 4 hours and still smell like smoke a week later. I met a lot of new folks from out of state that came in for the Pro, a surprising number of which said that they follow
this build thread and loved our little Mustang. Grilling on the open-top little portable grill we brought was no match for this hungry mob, so for Saturday night's party another Texas Region racer brought a 2nd grill, and together we grilled hundreds of chicken, brats, dogs and burgers until 10 pm. We killed 3 kegs of Shiner beer over the weekend, as usual.
Saturday morning many of us hurt - from eating too much food, from so much walking, from excessive beer intake - but we walked the courses one more time and then I headed out to work the course in the first heat. That was when Amy ran in L1 class, so she was on her own for set-up and had no help with tire pressures between runs.
The tires crept up almost 10 psi over her 4 runs, so that didn't help. She looked timid behind the wheel, which I kind of expected from her hopping into our STX prepped car just with some big R compounds and a rear spoiler slapped on. It takes her a couple of events on an all-new setup to adjust, but I was hoping 12 runs this weekend would short cut that learning curve.
She was fighting some fast women drivers in L1 and managed to snag 2nd place after her first 4 morning runs (2 left, 2 right). She drove her fastest runs of the weekend that morning, but one of them had a cone penalty - which she cleaned up that afternoon, but she never matched her best raw times from that morning. I don't have a single picture of Amy driving as I was working course when she ran. Unfortunately this was a pattern I mimicked, also running my fastest runs of the weekend in my first Saturday morning race heat (which you can see below in this 6 minute video - my 2nd left and right side runs there were my quickest).
Click here for Terry's 4 runs in heat one
Amy conveyed the tire pressure creep, and since she worked 3rd heat and I ran 2nd, she could help me with tire pressures between runs all weekend (hugely helpful). My first run was on cold tires and was a total throw-away - learning the course, learning the new grip limits of Rs on this car, driving off line in the heavy klag that this site's surface turns to in short order, and having no heat in the tires. By my 2nd left side run the tires had some heat, and the Mustang felt like it was one rails. It had an AWFUL steady state push, but still managed to put down power very well and on the final straight after the giant sweeper it was hitting the rev limiter in 2nd, so that's in the ~75 mph range. Brakes worked well, but it did get into the "funky steering feedback loop" issues towards the end of my last run. I could also feel the limited slip differential starting to slip badly in my 3rd and 4th runs, which I note in the video if you listen.
Left: We have spring rate changes already underway to prevent this! Right: But it happens to others...
more below...