Track Day 24 + 25 - Thunderhill East - Part 2 of bringing the trailer back

So as part of my adventure down south to pick up my Corvette with my new trailer and bring it home, I decided to try and schedule a track day to hit up on my way North. Thunderhill wound up having a weekend long track event which worked out perfectly as Thunderhill sits nearly exactly in the middle of the drive from the Ventura back North. So I left early black Friday, arrived at the track and unloaded my car, shredded the track all weekend then packed up one session early on Sunday and was home before midnight. Not bad, not bad!

I was pretty excited to get the Corvette out at Thunderhill. I'd been here once before in the past as part of a private track day on my sport bike. Getting back here over 10 years later in my Corvette was a fun little way to eclipse a bit of my past, especially as I've progressed a fair bit further with the car than I have with the sport bike back in the day.

The first track day I decided to run fast intermediate. I generally run advanced these days, but given I haven't seen the track in quite some time I didn't want to be out there wandering around aimleslly figuring stuff out. It wound up a reasonable enough decision as I was able to figure out the lines and traffic only stressed me out moderately. I did at times hold a few folks back, but one gentleman I caught up with said he was definitely way back on the throttle chasing me on the straights, but in the turns my corner speed was quite high so that helped me feel a bit less guilty about occasionally holding folks up.

I signed up for time trials for the weekend. Seemed like a no brainer since you get a bonus pretty wide open session for $50 a day, and pretty much everyone pretty much walked away with $35 off their next track day with the org so it was really just $15 for a bonus session. Worth it! I got second place in time trails in my category, but... there was only two people. So last place, haha. The other competitor was in a 2022 Chevy Camaro, which I wouldn't exactly deem that a fair match up as they have probably 200 horsepower on me and who knows what else. Still, they only beat me by 3.3 seconds so I think with a wing and some horsepower I could match them, or maybe even some nice 100tw tires! Although that level of cost per track day I'm not as excited about buying my way into a win. That said, the camaro also claimed to normally run 1:55 but had tire issues so... who knows and who cares? For all I know any issues I had were oversteer related as well.

Here's the track addicts info (10hz gps) I have from my best lap of 2:03.363 in time attack. It was by far my best lap of the day as I wasn't able to get a clear enough track in fast intermediate to ever have a fully clear lap. As you can see it's a pretty quick track with many sections in the triple digits. This also set a new on track top speed for my C5 of 123mph, so eat your heart out Willow Springs for claiming to be the fastest track of the west!

Video of my personal best lap:

The second track day was much colder, but less windy. In the end, I think the two track days were pretty much a wash. I was running 23psi cold though, and throughout a session the tires would heat up to 31psi. I'll need to take a closer look at my temps sometime though to really see what's up. I just gotta convince some friend to help come be pit crew for my car.

The track was much more open on this second day as less folks attended, and now that I had solid track faimiliarity and I had compared my lap times to others in advanced I knew I could drop into that group and for the most part hang. I scouted the pits, figured out a few vehicles I'd definitely have to get out of the way of such as a full aero LS swapped NA miata, and took to the track. Sure enough, I was mid pack as I expected. I had to let some people pass me, I smoked others, and I had a good time.

A track map of thunderhill east

Above is a track map of thunderhill East, which might help you reference any of the turns i'll mention in this last bit.

I did go off track once trying to maximize my drive into turn 14 I was always struggling there and felt like I was getting push mid turn from the front... which is a bit silly as I've got the most downforce up front. Oh well. I pitted, got a quick lookover despite feeling fine about the car and then went right back to shredding. I wonder what I can do to improve mid turn front end grip... more rake perhaps? A wing won't help, heh. Probably some suspension adjustments I could make.

A few improvements I made to my on track lines based on feedback from some people online and others in the pits:

  • No coasting. On gas or braking. Hold gas long brake harder instead. This helped pick up my average lap time and definitely picked up the intensity. Specifically this helped with turn 8, where I was frequently coasting a bit before it to keep my speed to the max for turn 8. Now I'd carry speed much later to turn 8, grab some brake to drop 3-5mph or so (guestimated, I don't watch my speedo) and then still make max speed on that turn. I'd also carry speed deeper into 10, and get on the throttle more through 9 versus coasting until I could see my line out. That last bit about 9 though was more about confidence the track was going to be where I was pointing than anything.
  • Set tires before going over a crest. As most of the crests (turn 3 and 5 / 5a bypass) are left handers I would just get my braking down up to the peak, then turn just a bit so the weight was already transferred to the outside tires. I'd then come over the crest and already have my weight settled to the outside.
  • In turn 2, brake later and trail brake. I was frequently braking up to the entry, then setting my turn and maximizing drive through and out of the turn. I started braking later and finishing braking about 20 yards into the beginning of the turn. This picked up some speed and time in general.

During the second days time trials I turned a 2:03.6, so .3 seconds off. I feel this was because I was coming into the turn 14 side by side with a C8 corvette, that just wasn't able to pull enough distance on me. So I lifted for the briefest of moments to give them the clean pass and line through 14 and then got back on line and on the throttle. I'm betting I lost at least that .3 seconds, if not more... but eh such is life. I still had a blast and I feel good about a 2:03 two days in a row. It gives me something reasoanble to aspire to as well my next time at the track.

Added bonus for the second days time trial though... I was the only person in my category this time! So I took first place!!!! Woohoo! Since it was hardly a competition, I gave the prize to Bella for being the cutest track pup. She wore her medal around the pits when I walked her and Everybody loved her. She couldn't help herself but get pets from everybody that she could, but did try and steal several peoples food. Such is the life of a Bella!

Overall, the weekend and the trip down south was a success. The Corvette held up well and trailer did great as well. I also now have a low key place to stack track outline stickers! This time around there were also zero issues loading and unloading the C5 at the track, so the ramps worked quite well!

One minor mechanical hiccup of note, I was getting squishy brakes again. I bled them, and yet again there were air bubbles on just the drivers side caliper. I think something is up on that side. I'll be reviewing it with downtime this winter.