I was invited to the Pro-Solo Test down in Moultrie this past weekend. Moultrie is quite close to the site of this year’s Red Hills Tour, way down there in the South of Georgia.
After the problems with the Pro-Solo system early last year the SCCA began a crash effort to fix the issues. A few events got cancelled, but an improved system was then fielded mid-year.
What I didn’t know previously what that a significant effort has continued since then to further improve the system to make it even more reliable and easier to operate. So last weekend the SCCA ran a test in Moultrie on the concrete pad at Spence Field to shakedown the revised software and hardware implemented since the end of last year and prior to the first points Pro-Solo event in a few weeks in Florida. We did a lot of starts and runs over 3 days, testing single-course, dual-course and challenge modes multiple times.
The system worked really well as far as I could tell. I got something like 60 full runs and an additional 40 or so practice starts on Friday which began wet and slowly dried a bit as we went along. (This went a long way to minimize tire degradation as I learned to launch the car.) The Corvette was awesome the entire time. The clutch never overheated and stayed consistant for every run the entire weekend.
Just before I left I received a set of upper shock bushings made from polyurethane which will be installed with the Penskes when they get here. Some people may not realize that these are legal in Street class. They should make a slight improvement in shock response. The Ohlins I had on the C5 had no bushings at all… they fitted metal to metal at the upper end and transmitted a lot of additional noise into the cabin. The Konis mounted now re-use the stock rubber bushings. I have them cranked down pretty tight to limit lost motion.
The two very short courses were not quite identical and that was a good thing. In fact, I wish they had differed even more than they did for additional variety. Both had a tight section that rewarded excellent braking, car control and a good knowledge of the braking understeer point for the front end. These sections also rewarded narrow cars and better transient response.
Of course the drag start rewards power-to-weight and forward grip. I think the rear 305 Falkens did a pretty good job of putting the power down once I really tuned into the feeling and sound of incipient wheel spin and could control the application of torque. The Sunday morning session contained my fastest times on both sides and is shown below.
In the picture above you have, from left to right on the top row, the clock time of the first run which happened to be from the left side, its sequential number in that session and that side, the total time of the run, the Reaction Time, and the time to travel the first 60 feet. Then you have the same data again for the first run on the right side. For those not familiar, the quickest left side time is added to the quickest right side for your total at a competitive event.
The sharp-eyed and clued-in may notice that the clock times look a little strange, i.e. they don’t all swap from side to side like normal as we cross-over behind the start, alternating side to side. This is true. After the second run, which was on the right, I pulled back into the right lane again to even up the lines of cars on both sides and ran my third run from the right side again. Later in the session I did the same thing but on the left side. This could never happen at a real event, but at this informal test things were laid back.
The red, crossed-thru time was a red light run, i.e. I left too early and crossed the start beam before it had turned green, which is 0.500 seconds after the last yellow light. I had been playing around a lot with my launch technique, but by this time I was getting reasonably consistent in the 0.6’s and 0.5’s.
The 60-foot times are a little slow with the best being in the mid 2.2’s. I attribute this partly to the cold conditions which limited grip. In warmer weather I’d hope to be running consistently low 2.1’s, but I’ll have to improve my launches some more to get there. Barry K. cut a few 2.0’s in his mid-engined C8. Donour S., owner of a Lotus Evora he’s taking to STU this year, was consistently in the 2.1’s and sometimes dipped into the 2.0’s. I expect he’ll cut some 1.9s this year in that mid-engined car that has over 60% of its weight on the rear tires similar to the C8. It’s not horsepower that nets good 60-foot times. The car has most of the energy it needs to get started well already present in the engine’s rotating mass. It’s grip and technique that make for good 60-foot times.
You can find a video of the last 8 of these 10 runs on Youtube here.
This concrete site is not big enough to have much in the way of fast sweepers and probably couldn’t hold a real Pro-Solo event, though it could host a single-course event nicely.