Meet-up
Whereas on many Sundays, one may not be out of the house until long after sunrise, this morning was different. This was race day. As the sun rose upon the (Si) Valley, we met up for a quick bite to eat and headed south to Marina Municipal Airport for the autocross event. Although I didn’t pack a lunch, I did pack a nice little breakfast bagel & egg sandwich with about 3 eggs in it. This helped give me a good supply of energy and I didn’t really feel hungry till late morning/early afternoon.
I’ve learned from previous events, that sufficient sleep and a good breakfast are critical elements to a good (and fun!) race day. I’m glad that I ate breakfast here, about an hour-plus out from the event location. Running the second half of the morning session and working the track in the beginning meant that there was plenty of additional time standing around for food to digest prior to the session.
I’ve had events where I was on very low sleep and may have been on coffee. I remember having a hard time keeping the car in control and making the quick, coordinated movements that are needed for autocross. Once, while heading to Laguna Seca, I grabbed some breakfast from McDonald’s in Monterey, maybe it was a Maple Oatmeal or an Egg Bagel. I think it was in the middle of the first session where I had to pull over because my stomach was getting turned upside down. No fun.
Moral: Get proper sleep. You know what that means for you. Eat breakfast an hour+ before the first driving session!
Arrival
Getting Acquainted
Driving on an autocross course is naturally going to be very different from driving on a road course. Especially when the road course is something like Laguna Seca, which has been virtualized in numerous racing video games, there’s a good chance you are already familiar with the lay of the land and what type of turns are where.
Driving on an unfamiliar road course, for example, Thunderhill Raceway which is not in any games that I know of, can be a bit unsettling at first, but within the first few laps you’ll quickly get the hang of it. Since those laps are back to back, you can grasp the rough course layout pretty quickly in the first session.
Autocross is quite different in this regard. Almost every event presents a new course layout. Unless the layout is a repeat from the past, the turns are rarely in the same sequence or location. This makes the need to arrive early and walk the course, so much more essential! There’s no 20 minute long continuous first session where you can lap the course over and over again to get familiar with it in the morning, and guarantee to be familiar with the course by the afternoon. In autocross, you only get a handful of (1-lap) runs, each with a gap between it, so each and every lap must be put good use.
Arriving just as the coursewalk had ended, our group didn’t get a chance to walk the course prior to the first session. I felt so lost on the first one and completely skipped one of the first turns, as I wasn’t sure where to go. I ended up having to reverse out of it to continue along the proper path.
You can see me fumbling my way through the first lap here:
Immediately after my first run, I jumped into a friendly Z06 owner’s car for a ride along and that quickly helped me get much more familiar with the course layout. I was also blown away by the sheer amount of power that Vette had. The driver must have been driving the entire lap at under 40% throttle. There was one segment where he might have gotten close to 100% and even though he missed the next turn because of developing that speed, I had the biggest smile on my face for the rest of the run. The force with which that power pushed me back in my seat was incredible!
Session Recap
Plenty of variety at this Corvette club-sanctioned autox
What follows is a breakdown of my reflections of how the car performed in this event in various areas of performance. It’s a fairly raw reaction and is not meant to be definitive or advice in any way.
I cover the areas
Tires
Brakes
Power
Suspension, Body-roll, and Weight Reduction
Limited Slip Differential (LSD)
Tires
I’m very happy with the performance of the tires during this autocross session! Alhamdulillah (All praise belongs to God)
Having completed my maze orientation during the first run, I managed to stay on course the entirety of the second run, which is where the tail-sliding action began. This course had a special loop section which was nearly a 270 degree turn that crossed over into itself. It had a nice straight on the entry allowing some speed to be brought into the turn, say 40 mph or so. The turn itself seemed to go on for days, so there was plenty of room to play with the throttle input mid-turn and feel the car’s response.
There was a good amount of understeer on entry while trying to get the car to rotate. So long as I didn’t add too much throttle here, understeer was the dominating limit. Also, bear in mind the tires are still very cold at this point as it’s the first run.
The first run where I stayed on course, I power oversteered and had the back slide out on me in full-on drift theatrics. The car was still composed, however, even while sliding and it didn’t feel like a snap-oversteer as it may have in a Miata or MR2 for example. Instead, as soon as I backed off the throttle input, I felt the car return to the driving line. And then, since my passenger Bilal was recording video, I childishly dug my foot back into the throttle for a second slide. Only this time, Perhaps I gave it a bit too much throttle, and I had to do a strong countersteer at the end of the slide in order to keep the car moving in the right direction.
Some tail-sliding action:
Having had my fun on the initial slide, in later sessions I found that the car was very responsive to fine modulations in throttle input during this turn, and that it felt surprisingly controllable during the slide. More controllable than I expected it to, this being a relatively short wheelbase car and the tires being upgraded in compound & width (225/255 RE71R).
While minimal throttle input and maximal steering input resulted in a good amount of understeer, I really enjoyed and was quite impressed with how progressively the rear end slid out under power. I noticed that by feathering in just a slight amount of throttle input, I was able to trail on the edge of oversteer and get the car to rotate through the turn with a slight and continuous slide. I didn’t discover this till the later runs.
On the Edge of Traction:
I believe that a good portion of this behavior can be attributed to the tire compound and construction, which lends it the properties of providing a gradual loss of traction at the limit, as opposed to tires that are super sticky that may break free completely when they slip.
Later, I inspected the tires and noticed the blobs of rubber that looked like they were splattered on to the tire. This indicates to me that the excessive understeer resulted in the tires overheating to the point where the rubber began to melt slightly, although only in small spots <5mm in diameter. I imagine that these spots of liquid or nearly liquefied rubber cooled down at the end of the turn and resolidifed, leaving the tire with apparent blobs of rubber that look like they had been splattered on to the tire. While I think my explanation is way cooler, a quick google reveals that this is probably just marbles of rubber I picked up on the course that were shedded from other cars’ tires.
Brakes
As far as brakes are concerned, the brakes did not even close to heat up to temperature. Only after leaving the event, did I feel a strong braking “bite” as we headed back via “the” (Hwy) 1. During the laps, I didn’t feel that bite that I’m familiar with when the brakes are warmed up, and I really had to stand on the brakes to scrub off speed while approaching a turn hot.
A future session might have better braking performance if I get started on the initial lap with a few heavy brake applications to get things warmed up. This will also be easier if I arrive early enough to walk the course so I know where I can speed up.
Power
From a power perspective, the car had more than enough power to break loose on command and sustain some power oversteer turns. The only place where I felt power was a limitation was on the two full U-turns (towards the upper left side of the course map) where I was suggested to downshift to first. That would have definitely given me the power I needed, but I decided to keep it in second to avoid putting that stress on the transmission with first gear being known for its sensitivity.
A little more low-end torque would be pretty sweet here, because entering those U-Turns at about 3k RPM meant that there was a long way to go before VTEC powerband was ignited. It mattered even more so because each U-Turn led into a long straight, so it felt like the opportunity to be at WOT was not being taken full advantage of because of how slowly the car was picking up speed. My passenger said “punch it!” even though I already was, lol. I’m not sure what type of upgrades would enable 240WHP at 3K RPM, as I’m sure most upgrades will focus on the higher end of the power-band.
Having the intake airbox cover off probably didn’t help with power production, athough it did sound JDM Tyte Yo. No joke, it sounded really nice. I put the cover back on for the later runs, after the engine and the environment began to warm up.
Launches were smooth, alhamdulillah, I revved up to 3-4k and did a semi-quick clutch engagement, but not close to a clutch dump. Just enough to hop off the line.
Weight, Suspension and Body Roll
Weight was fine, I don’t think this was a limiting factor. In fact, with the amount of oversteer I was playing with, I feel (and have felt before) that emptying out the trunk is not necessary and may be detrimental to the car’s overall stability. It’s quite possible that the designers of the car included the weight of the spare tire and tool kit while optimizing the weight distribution of the car. Next time I might just leave these in place.
I softened up the rear suspension setting by about 5 clicks or so. I’m honestly not sure what settings the coilovers were set at before, I just know they’re softer now than they were. That seemed to help, but it’s hard to qualify how exactly. I might say that it contributed to a slightly smoother oversteer.
Body roll, I didn’t notice it. The car felt planted and went whichever way I pointed it. Loving the agile-response with these HKS coilovers.
Limited-Slip Differential
However, the run immediately after I softened the rear coilover settings was the first time I can recall feeling the LSD engaging! I’m not sure if these are related. However, during the sharp U-turn at the upper-left-most corner of the coursemap, as I was coming out of it, I felt like one wheel was spinning as I feathered into the throttle. As I gradually let off the throttle in the middle of the turn and I felt a moment where the LSD locked in and both rear wheels began receiving power together, in mid turn.
I’m not sure if that describes the behavior that is intended by the LSD, but thats what I felt. This makes me consider that replacing the rear differential fluid might help improve its operation. I imagine that if the diff fluid was better, while throttling out of the low speed turn in second gear, the LSD should have already locked the axles together and delivered power to both rear wheels. Instead, the throttle input was dumped into a single slipping wheel in Open-Differential fashion, and it wasn’t until I let off the throttle slightly, that the two sides engaged and I felt the traction I needed to power out of the turn.
It’s possible that because the fluid is very old, it’s over-lubricating, or somehow allowing the clutch in the diff to continue slipping when it shouldn’t, thus resulting in single wheel-slippage during the turn. Although I would expect old-fluid to under-lubricate rather than over, so I’m not too sure what’s happening here.
Overall
The end result is that I am feeling like nothing needs to be changed on the car for it to have gone faster during this weekend’s event. Rather, I simply need and would like more experience on the course, and to get more comfortable driving the car at its limit. If I were to choose a single area where I would like to target an improvement, it would be the low-end torque and power output of the engine. Getting a little more ‘oomph’ while outside of the VTEC powerband would be nice.
Everything else: top-end power, brakes, body-roll, etc, felt amazing! mashaAllah. The car has plenty of power to break loose on the turns and to pick up speed on the straights. It’s light enough to take sharp turns without leaning too much. It stops quick enough, just need to heat up the brakes better. It turns very sharply, again heating up the tires would also help a lot here, but such is the nature of autox.
Other than that, the car does what it’s designed to do. Be a nimble monster at 6000+ revolutions per minute. It is, 100%.
Event Overview
The club was well organized, although some complained that it wasn’t. I was a bit surprised by the Star Spangled Banner being played at the beginning, just because I’ve not seen that done at any other autox event I’ve been to. From arrival to departure, I was there (although I should have arrived earlier to walk the course) from 8:45am to 1:30pm. Not bad for a day out at autox! Some previous days with other clubs, I’ve gone out from more like 7am to 4 or 5pm, which is a much bigger investment for the day considering that I’m usually driving out to an autocross event the day-of. Although there were plenty of folks who were staying in a hotel nearby for this weekend-long event, such as this Tesla owner…
Tesla Presence
I was definitely surprised when I saw this Tesla Model 3 at the event. I had the opportunity to speak with the owner and was intrigued to learn that the range-hit from the previous day’s autocross was only about 60 miles of the overall charge capacity. Bear in mind, this is one of the longer autocross courses I’ve seen setup. That’s quite impressive!
It also speaks to the club’s welcoming nature, and I definitely felt welcome as a newcomer in a non-Corvette at this event.
Up Next
Overall, I had a lotttt of fun getting down on this course, which was hands down the longest autox course I’ve run. With times ranging from the 60 – 80s per lap, there was plenty of drive time to really enjoy the lap.
My times progressively increased, starting from 1:14.488 down to my fastest time of the day of 71.930.
At this point I’m highly motivated to join a club for next year, though not sure which. The Lotus Club GGLC was spoken highly of by my cone-working mates, but I really like the half-day format of this event. If that’s how all the Santa Clara Corvette Club’s events are run, then I’m far more likely to join this club’s season. The extra long course, combined with half-day (as opposed to full-day) format, and friendly folks are all strong points.
Even though autocross runs are relatively quite short compared to Time Attack, the low cost barrier to entry and lower wear on the car means that it’s much more feasible to go back more often. Going back more often means being more connected with people in the sport, and learning about more ways to do what I love to do, even better. I think it’s a worthy investment in something that I really enjoy!
Seriously, the very last session of the day, when I finished the run, I felt the adrenaline pumping throughout my body. I felt so excited to have completed what I really felt was one of my best runs of the day, and it was, alhamdulillah. I had so much fun moving the car along through the course, and it felt like I was orchestrating a symphony while I did so. At the end of the run, I felt so excited when I was handed my timeslip. A feeling worth exploring further, inshaAllah. Thank you to Allah for making his day possible. Alhamdulillah. And for getting to go with friends, which was one of if not the best part!
Credit to Bilal for recording all the videos!
Comments