It's April in the Southeast region, which means it's time for the Spring Brake event at Roebling Road Raceway in Savannah, GA. Roebling is a fast track, and though it looks simple in map form, getting a decent time requires some finesse and a bit of bravery.
This April marks our fourth event here, and so still learning the nuances of the track; there's much room for improvement. Additionally, the Friday practice session was a great opportunity to test setup, and was able to get some interesting indications of wing performance of the APR wing currently on the car.....more to follow on that topic, in a separate post.
Saturday, April 6th
Saturday started with great conditions: cool (low 60s), dry, little humidity. We started the weekend on 2017-model Continental race slicks designed for the front of LMP3 cars. The tires had 8 or so heat cycles. Despite the optimal conditions, the car never felt planted; though completely controllable, the car wanted to push moderately in most corners, and the tires would start graining after two hot laps. The tires felt as like they needed two laps to warm up, and then fell off after the third. As a consequence, never felt comfortable in the morning sessions, and lap times were weak, at best. Previous event at Roebling, managed a 1:21.5 in TT3 trim, with stock aero and used Hoosier A7s with 9 heat cycles. Struggled to better that time this weekend, even with aero and 40 more hp.
After consulting fellow Time Trialers, Johnny Miller from Track Day Tire (and former Trans Am and NASCAR pro) and Matt Isbell with Zen Racing, the tires were the most obvious issue, aside from driver incompetence. With rain likely on the horizon around the lunch our, we decided to get trackside vendor Appalachian Tire to mount up some fresh Hoosier 315mm A7s.
As luck would have it, the afternoon rain turned into a full downpour from lunch until the awards dinner, so we were stuck with a poor showing waaaay down the order, 4th in TTU and 13th overall. Disappointing would be an understatement. Saturday Results
Sunday, April 7th
After regrouping with a pleasant evening in downtown Savannah, arrived back at the track nice and early on Sunday with hopes of salvaging at least a little dignity after Saturday's ass whipping. Hopes were further spurred on by the prospect of running the maiden voyage on brand new Hoosier A7s!
Consulting again with my garage mates, it's evident I've been running far too much tire pressure in the past. Conditions were slightly damp and cool, so set the cold pressures to 27 psi and headed to the grid. Because of my poor showing on Saturday I was stuck back in the middle of the grid, but was okay with it as I intended to take it a bit easy on the out lap.
After getting a good scrub on the tires on the out lap, and a gentle second lap staying off the curbing, it was time to see how much more grip we had. Starting back in 14th for the session meant we had to deal with a healthy helping of traffic. But we slowly worked through traffic throughout the session, progressively pushing harder with each lap. In the six laps that session, never found the limit of the tire......it just kept gripping harder the harder it was pushed.
Even with the heavy traffic during the session (passed at least one car per lap, never had a clean lap), the tires improved times by a full three seconds compared with similar conditions the prior morning. After pulling into the garage, Johnny asked how the tires did; I could only shake my head and laugh; now I know why they're called "purple crack". Had to take a 10 minute walk around the paddock to cool off before resuming my post-session routine.
An incident with a stranded HPDE car meant our second session of the day was limited to one lap. And the expectation of heavy end-of-spring break Atlanta traffic meant we had time for only one more session for the weekend. By our 1:20 afternoon session, temps had climbed to the mid-80s, so the track was obviously going to be slower than the morning session. Even so, was hoping for some clean air to see exactly how much more grip these A7s had versus the previous Continental slicks.
Was gridded towards the front this time, right behind one of the TT1 cars (roughly 170whp more than my C5 currently pushes), so the session goal was to stay on her tail. Much to my surprise, mission accomplished! Though my target time of a 1:16 wasn't achieved, a .8 second improvement to a 1:17.9 in degrading track conditions was very satisfying. And, considering most other drivers failed to improve over their morning times, a .8 second improvement was pretty big. Additionally, that put me 6th overall, and 3rd in the TTU class. Considering the group that beat me included two track record holders (TT1 and the new TTU record holder, Matt Isbell in the Zen Racing LMP3), a former pro driver, and two others with > 150 more whp, I consider the day a success. Sunday Results
So, take-aways from the weekend are:
1. The wing has to go. But this will be a subject for a future post.
2. Yes, sticker A7s deserve the name "purple crack".......it's a whole new level of grip.
3. Even in my current TT2 trim, a 1:16 is immediately available in decent conditions, and a 1:15 should be the future target once I find a bit of bravery.