Flocktoberfest

This weekend I went to Flocktoberfest. What the heck is that? The tagline was “Racecars, Beer, and Chickens”. Yup, that about sums it up. The event was held at Faster Farms, a chicken ranch owned by Gavin and Kristen Hembree. It was co-organized by Cathy Fuss, the owner of Lucky Dog Racing. The property has lots of chickens and lots of racecars. Various teams store their cars there. In addition to a few endurance cars, I saw a couple Spec-944s and Spec Miata. People also brought their cars to the event. The iconic UDC (upside-down Camaro) was there along with Tinyvette and the Faster Farms land yacht (pictured)

The event was a gathering for endurance racing folks. Lemons, Lucky Dog, and ChumpCar drivers and cars were there. I met some new people who share the same (silly) passion. I also got lucky and won a couple raffle items. One was a car wash kit. If you know me, this is either the best or the worst gift ever (I never wash my cars). The other was a framed print of the event poster. That’s a nice commemorative piece I’ll be happy to hang on my wall.

IO Port racing had a truck there, and I bought a new window net. They also did a safety demo where they burned various kinds of material. I had never seen what happens when you put a blowtorch to Nomex. It just turns brown, but doesn’t burn. Try that with cotton, nylon, or polyester and you get a very different experience. Cotton burns clean but the plasticky stuff makes a drippy mess.

Flocktoberfest is supposed to become an annual event. I hope so. Attendance was pretty good (maybe 100) for a first year, and I expect it to get bigger and better. I’m not a beer drinker, but I’ll return for the tacos, band, raffle, cars, chicken, and most importantly, the camaraderie.

Upcoming

Next week will be the first race for my Yaris. I’m taking it to the Lucky Dog event at Laguna Seca. I’m very excited to finally race it, but I’m also more nervous than usual because I don’t want it to get damaged.

Looking over the page statistics, the most popular posts are on how to drive faster. Well, the next series of posts I have planned are on passing, but after those I’ll get back to technique. Oh, and also more crashes.

Obligatory video

Apparently the Brits love MR2s so much that they have a racing series for all 3 versions. The second and third versions are about the same speed. After the POV car spins out near the end of the video (due to on-track praying), you can see the AW11s at the back of the pack.

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Budget Racing Builds

Do you want to build a car for endurance series like the 24 Hours of Lemons, American Endurance Racing, ChumpCar World Series, Lucky Dog Racing League, or World Racing League? Here are my thoughts on that topic.

Cheap, fast, reliable: pick two

This post is about budget racing, so cheap is non-negotiable. Also, in my opinion, the whole point of racing is the driving. That means being on track, not running to the junk yard to find obscure parts. That means reliable is non-negotiable. The good news is there are lots of cheap and reliable cars out there.

BMW or Mazda?

When it comes to budget endurance racing, two brands stand out: BMW and Mazda. Popularity is a good thing. It means that maintenance, tuning, and repair expertise is near at hand and that spare part you need is probably already in the paddock. Mazda Miatas are the most popular track cars now, and have been for some time. They are robust and so light on consumables (fuel, tires, brake pads) that they are very cheap to run. In addition, they have the highest corner speed, which makes them incredibly fun to drive. Before the Miata was the de facto club racer, there was the RX-7, which is also a good choice.

BMW 3-series are rugged and handle extremely well. The BMW 325 in the e30 or e36 platform is a fantastic track car. Each one is almost as popular as the Miata, and e46s are also becoming very popular. Although less common, the 5-series cars also make great endurance racecars. The 2.5 liter inline six is plenty of motor. The 1.8 is very durable and burns very little gas, but few teams are able to make it competitive.

There are lots of other cars that make good endurance racers. Volvos are the most reliable in Lemons. Simple FWD cars like Civics and Escorts do well. If the car is light, which it should be to keep consumable costs down, you don’t need much power.

Build or Buy?

When sold, racecars return about $0.25 on the dollar. An inexpensive $10,000 build is only worth about $2,500. That’s bad news if you ever want to sell a car, but great news if you want to buy one. In order to be competitive in Spec Miata, you need a 1.8 liter engine these days. That means there are lots of 1.6 liter racecars available for cheap. You can also find RX-7s that were former SCCA/NASA racecars. Expect to pay more for an e30 (Spec E30) or e36 (Spec 3) racecar because they are (a) less common (b) more expensive to build (c) BMWs.

As you peruse Craigslist, RacingJunk, racing forums, classified ads, etc., you may come across some can’t miss deals. Some of these will see you spending more money than a Mazda or BMW in the long run, even if you picked it up for free. You know that car that you coveted in your youth? It will break your heart and your bank. Racing is hard on cars. Use your head, not your heart.

Mandatory Upgrades

If you decide to build a car, there are certain things you absolutely have to upgrade or at least replace.

  1. Brake pads. Stock brakes are generally fine but OEM pads are not meant for racing. Brake pads work in defined temperature ranges. OEM pads are designed for stopping you when the pads and rotors are cold. Race pads are for when the pads and rotors are hot. At a minimum, get a ceramic pad designed for autocross. But you really want a pad that was designed for full on racing. Replace all the rubber hoses and replace the fluid with something designed for racing.
  2. Suspension. Replacing tired/worn suspension isn’t necessarily going to make you that much faster, but it will prevent you from getting into some bad situations and help you drive out of those you do get into. It’s okay to have some body roll, but you don’t want the car bottoming out or wandering around on you.
  3. Oils. Replace fluids as often as you can. Frequently changing  engine, transmission, and differential oils prolong the life of those components, which means you’ll have fewer lost days at the track. In endurance races, cars go home early all the time due to failures in these components.
  4. Tires. The simplest way to improve the performance of your car is to upgrade the tires. There are a large number of 200-ish treadwear tires on the market. Some are stickier than others and those also tend to wear out the soonest. See the end of the post for more thoughts on tires.
  5. Fueling. Another really simple way to improve your performance is to spend less time in the pits. Remove the ball valve in the fuel filler neck and figure out how to safely empty a 5 gallon tank into your car in under 30 seconds. Fuel spills can take extra time to clean up, so make your fuel filling routine as foolproof as possible.

Electronics

Every racecar needs at least one camera and some kind of telemetry device. Cameras are important for training and critical to untangle fault in an incident. Don’t go racing without a camera. It should be mounted to the roll bar with the driver in the field of view. Adjust the vertical position of the camera so that it also captures the rearview mirror. There are so many choices when it comes to cameras. You can go with the usual GoPro, but even dashcams are fine. I have a Mobius ActionCamera powered by a USB cable connected to the cigarette lighter. It shoots whenever the kill switch is on. It is set up to record in 1080p and lasts about 10.5 hours with a 64GB card. I also have a Tomtom Bandit for head-mounting and other uses.

To improve your driving, some kind of telemetry device is very helpful. There are two basic flavors: (1) immediate driver feedback (2) data loggers. Some devices do one, others do both. For driver feedback, I like the RumbleStrip DLT1-GPS. It shows your current speed and lap delta (difference between this lap and last lap at this position in the track). For data-logging, I use an Aim SoloDL. While the Aim also does predictive lap timing, I like the big red LEDs on the RumbleStrip. Smartphone apps can also be very useful. They have the ability to do feedback, data logging, and even video overlay. But the quality is usually a little less. An external GPS unit can improve things I hear, but I prefer dedicated devices.

Tires

Budget endurance racing series have converged on tires with 200 treadwear ratings (and some allow 180). There are a lot of tire choices. One of my favorites is the  Falken Azenis RT615K in 195/60/14. Yes, 14″. These routinely go on sale at Discount Tire Direct, and with free shipping and no tax, you can have them shipped to your door for about $85 per tire. They have good grip and are very durable. You can get about 25 hours of racing per set. If you have a Miata you may already have the 14×6 7-spoke rims that weigh less than 11 pounds. If not, you can pick them up cheap. BMW e30s came with 14×6 bottlecaps that weigh about 14 pounds. The nice thing about these rims and tires is that they are a breeze to mount with a $40 Harbor Freight manual tire changer. Wider tires with shorter sidewalls are a pain in the ass. The problem with 14″ rims is that there isn’t much choice for tires (there are Dunlops in 185/60/14, but they are much more expensive). Also, wider tires are faster.

Once you get to 15″ wheels, there are over a dozen that have 200-ish UTQG ratings. The sticky ones, like Bridgestone RE-71R, tend to wear out quickly. Although the treadwear rating is supposed to be indicative of how long they last (and therefore inversely proportional to grip) this number is controlled by the manufacturer (and their marketing department). Some 200-ish treadwear tires are more like 100 and some are more like 300.

  • BF Goodrich Rival – they are on the quiet side
  • BF Goodrich Rival S – never tried them, but they are often equated with RE-71R
  • Bridgestone RE-71R – fastest 200
  • Bridgestone RE-11A – middle of the road
  • Champiro SX2 – no idea, but some time trial folks win on them
  • Dunlop Star Spec II – most popular?
  • Falken RT615K+ – equally most popular?
  • Federal 595 RS-RR – cheapest and surprisingly good
  • Hankook R-S4 – liked the R-S3, and this is supposed to be better
  • Kumho V720 – seen bad stuff happen to these
  • Maxxis VR-1 – more PSI-sensitive than others I hear
  • Nitto NT-05 – lots of audible feedback, cheaper than most
  • Toyo R1R – supposed to be very soft, good for rain
  • Yokohama AD08R – also supposed to be a good rain tire

Obligatory Video

In the UK they race Jaguars as if they were crap cans…

Race Report: Buttonwillow

This weekend was the 24 Hours of Lemons race at Buttonwillow. My previous experience at this track a couple years ago. We had just rebuilt the MR2’s 20V 4AGE motor and travelled to Buttonwillow for a test day. After months of anticipation, 4.5 hours of driving, and $175 in track fees, my anticipation was at an all time high. The plan was for me to about 10 laps and then hand it over to my teammate/mechanic Bill. The moment I got in the car I was having such a good time that I had made a mental note to myself that I wasn’t planning on coming in until I needed fuel! I kept thinking to myself, “this feels like a racecar”. And it did. For all of 3 laps. Post-mortem analysis showed that all the bearings were spun. I feel the pain of that still.

This weekend, I brought down a much more reliable car, my B-Spec Toyota Yaris. It’s not a Lemons car, but I like taking it to test days before Lemons events because it’s the best bang for the buck. I can go on and off the track all day long for the price of a typical HPDE day. The icing on the cake is sharing the track with all the fun Lemons cars. I carpooled with John Pagel (Tech Chief of Lemons and owner of Evil Genius Racing). He towed me down and let me use his pickup-bed camper as my home for the weekend. What a guy!
I had two goals for the test day (1) learn the track (2) do a comparison test of Bridgestone RE-71R vs Federal 595 RS-RR. The 71R is the top of the line 200TW tire. Lots of people feel it’s more like a 100TW, and if you look at the NASA PT/TT rules, they equate it with some DOT R-comps. The RS-RR is the least expensive 200TW tire. I got them for $80 each.

I ended up doing a little coaching on Friday. A rookie racer asked me to drive her around the track since she hadn’t raced before. We did that for a half-dozen laps and were treated to a great mix of race situations. She got to see a car spin directly in front of us, idiots not using their mirrors, drivers using point-bys (or not), emergency vehicles doing live tows, yellow flags, white flags, and a Yaris embarrassing many faster cars. Later, she even drove my car. In Lemons spirit, I didn’t charge her anything and later they fed me. I also drove some of our team around the track as we were all new to Buttonwillow.

Speaking of the team, “NSR. Nut Sack Racing”, there were four of us: me, the car owner, a Lemons veteran (with decades of experience racing dirt bikes and sprint cars), and a rookie (with lots of jetski racing experience). The car was a 1980s Celica with a Ford 5.0 engine and an automatic transmission. It looked like it was from a Mad Max set.

The car passed tech easily and given a C class rating. Apparently they didn’t think we would do very well. Looking it over, I didn’t think so either. There was a smallish fuel cell that was supposed to last 2 hours with 12 gallons of fuel. My Miata and Yaris burn more than that… The tires were some off-brand summer tire that had already seen a couple races and didn’t look worn. The brakes were stock (disc front, drum rear) with OEM replacement pads. Despite this, the team had very high hopes. In fact, we thought we were practically guaranteed a first place win in C class if we just kept the car on track.

We started the day with the owner behind the wheel. He put down a 2:29 as a fast lap. Unfortunately, there were others in C class doing 2:24. Cheaters! Oh well, the plan still held. Stay on track and out of danger. After an hour and 40 minutes we got a radio call that the car had run out of gas. As we sat waiting for the tow truck to bring it in, we relaxed a bit because the race was most likely ruined.

I was next in the car. It stalled when I stepped on the pedal. Twice. Apparently you have to be very gentle at low RPM. The car was set up with a 2 gear shifter. After pulling it from Park to Drive, you put a trailer pin in the shifter so that it can only switch between Drive and L2. Then you just slam it up and down to change back and forth between the 2 gears. Whatever. I just left it in Drive the whole time.

From the moment I got on track, I pretty much hated the car. The brakes were terrible. Tiny OEM rotors and pads do not belong on a car with a 5.0L V8. You could use the brakes at most once per lap. Aggressive braking causes them to fade almost immediately. The motor, which is clearly the high point of the build, is good on the straights but weak in the corners (or so I thought). Unfortunately, you can’t use it fully on the straights because you have to coast long before the brake zone to keep from melting the brakes later.

How was the handling? Strange. Despite a much heavier front end than stock, there was massive understeer on corner entry. Mitigate that with trail-braking you say? No, I had to save the brakes for emergencies. Also, the brake bias was set too far to the rear, making such techniques a little sketchy. Once on throttle, the car behaved okay, but the suspension bottomed-out at several places on track. The net result is that a 2200 lb Celica with a 240 HP engine was slower than my Yaris (2250 lbs, 100 HP). The best I could manage on Saturday was a 2:24.

About an hour into my stint, I smell oil and look around to see which car it is. Mine! I am practically skywriting down the back straight. I pull into the pits and we look under the hood to find transmission fluid has coated the entire engine bay. Turns out that one of the hoses going to the transmission cooler sprung a leak.

The next driver out was our rookie. He only drove 30 minutes because the judges kicked him out of the car for spinning off course 3 times. It’s a poor craftsman that blames his tools, but in this case the brake bias was partly to blame. None of the other drivers spun, so this was also a case of the driver not having the experience or ability to drive around the problem. I realized very early on that the brake bias was bad. So I always did straight-line braking.
You don’t get 3 black flags in Lemons without having to do something embarrassing. Our driver had to read a novel aloud. Sounds mild until you realize that it’s a NASCAR romance novel. Yes, they make romance books for men in which NASCAR racers bed cars and drive women. The page was turned to a sex scene. I’m an avid listener of books on tape. This was not a 5 star book or performance. Riveting though.

Our next driver was our most experienced racer. He’s got a long dirt racing resumé on 2 and 4 wheels. His career highlight was a $30,000 purse in a sprint race. He’s also raced Lemons a few times. So he knew what he was doing and drove an uneventful session. Over dinner, he told me that the transmission did a good job slowing the car down if shifted to low. Something to try next stint. Day 2 started with the same driver. He put down a couple of 2:31s but eventually got black flagged when he spun.

I got in the car next, excited to try out the transmission. Holy crap, it works. Both ways. On the way into a corner, I would hold the brake pedal down for a couple seconds, then shift to low and let the transmission do some work, then trail off the brake as I entered the corner. Once I hit the gas, the motor responded with a satisfying growl. On the straight, not much could keep up with it. Unfortunately, Buttonwillow has a lot of corners and the combination of tires and suspension really held it back. With a big brake kit, working suspension, 200 TW tires, and a larger fuel cell, this car could be on the podium in the A class.

The two race days were so completely different. On Saturday I was constantly shaking my head and praying I wouldn’t hit someone. On Sunday I was grinning and laughing. What changed? The brakes a little, but mostly my attitude. There’s a personal lesson in that. I need to be able to change my attitude faster than overnight.

I’m used to driving a momentum car, so it was a great thrill to be on the other side of the fight. It’s so much less work to pass someone on the straight and then park it in the corner. On my last lap I had a great couple of corners and a wide open track in front. It was going to be my flier. But I got a little too ambitious and went 2 off in Cotton Corners. I wasn’t sure if that was going to be a black flag today or not, so I went in to talk to the judges. No penalty, but I decided to end my stint anyway. Although I ruined what was going to be my fast lap, I still managed to record a couple of 2:19s in the session.

The next driver our was the rookie. He made a huge leap from the previous day and recorded a couple of 2:25s. Unfortunately, he came back to the pit on a cable. He spun off track (collecting another black flag – 4th if you’re keeping track) and then couldn’t restart the car. Back in the pit, the battery was reading 9V. We surmised that he drained it trying to restart. After charging the battery for a while, the car finally took the track with the owner at the wheel. Unfortunately the alternator was also going bad, and he came back after a half dozen laps.

We finished 4th or so in class and I had the fast lap in the class. The guys on the team were really great to hang out with. It was a typically great Lemons weekend. I really appreciated having my own living quarters on track, and that’s occupying my thoughts a little too much.


If the main reason you’re reading this incredibly long post is that you want to know if Federal 595 RS-RR is your next endurance tire, I had better finally say something on the topic! The RE-71R is faster. How much faster? Hard to say exactly. I was carrying a full load of fuel, the temperature was much higher, and there was more traffic. Even under those conditions the RE-71R is faster. Under the same conditions, I’m going to guess 1-2 seconds on a 2-3 mile track. If you’re at the pointy end of performance driving and rules prevent you from using R-comps, the RE-71R is a great choice. But it doesn’t last very long. In a typical endurance weekend, you’ll probably change tires between days. The current price of an RE-71R at DTD is $131. The RS-RR cost me $80, and look like they will last an entire weekend. Without considering mounting, the RE-71Rs will set you back $1048 while the RS-RRs are $320. Add mounting costs and the difference is about $800 per weekend. Some people will look at that and say “$800 is too much to pay” while others will say “$800 is a bargain for 1-2 seconds”. I’m planning on using the RS-RRs for the upcoming Lucky Dog race at Laguna Seca. If we find ourselves challenging for a class win, we may switch to RE-71Rs to get those precious seconds.

3 years of YSAR

Did I really start YSAR 3 years ago? Well, this is post #156, so I guess that’s a fact. If you’re a YSAR visitor I want to say thank you for reading. It’s been fun sharing my thoughts with you. This week I want to reflect on a few related posts from the last year to create some kind of synthesis.

Last October, I wrote a pair of posts about the fastest line through a 90° corner. Does the line change if the car is a Miata vs. Corvette? Does it change if you’re on a race track vs. ice? I “solved” this problem using a simple-ish formula with circles of various radii. Turns out, if you’re driving a Miata, yes, the line matters a lot. Take a late apex most of the time, but make it a little earlier in faster corners. If you’re driving a Corvette, the line doesn’t matter that much. Driving on ice? The typical late apex is the worst line and early apex is the best. Huh? When you have no grip, and therefore no acceleration, you might as well keep your speed as long as possible.

In December, I wrote about the theoretical fastest path around a pair of cones. Should you drive a tight radius to minimize distance or large radius to maximize speed? Once again, I put some math to this problem and it shows that a tight radius wins every time. The only exception to this is if you’re not allowed to use your brakes.

These theoretical posts above were based on the typical tire model that states “there’s only so much traction, and you can use it for cornering, braking, or some mixture”. A little later I wrote about how the traction circle isn’t a circle (or a diamond, which is another valid way of drawing it). That is, grip can’t simply be divided into braking and cornering. There’s more traction available for cornering than braking, and mixing them a little is better than not mixing them. So trail-braking and early throttle application are techniques one should try to master because they maximize the use of your tires.

So the theory isn’t quite correct, but does the model hold up well enough to be useful? Is the shortest path around a pair of cones the fastest? I got to test this on a skid pad in August, and the answer is yes, the shortest path is fastest in the real world. If there is a long straight afterwards, then a late apex will win. When optimizing corners, it really comes down to a question of the straight that follows the corner. Is it worth throwing away some positional advantage to gain a speed advantage? Shortest path or largest radius?

So what’s my point in reviewing these posts? They were a great learning experience for me. I enjoy bouncing back and forth between theory and practice. When it comes to performance driving, the learning is as rewarding as the driving. As we start heading into the racing off-season, I urge you to read a book or two on racing. Brush up on the theory and see if you can put it into practice. For my homework, I just purchased Keith Code’s “Soft Science of Roadracing Motorcycles”.

The Ideal Student

As I was driving home from a particularly good coaching day at Thunderhill, I started thinking about what makes the ideal driving student.

  1. Safe. Safety is always the #1 priority doing something as dangerous as high speed driving. Safety doesn’t just mean being able to control the car. A safe driver has enough mental capacity to do other things while driving. Like watching out for other cars and listening to the coach. A safe driver is also prepared. Rushing creates errors both on and off the track. Arriving early to the exercises and grid is always appreciated.
  2. Humble. The best students don’t have inflated opinions of themselves. They want to improve and want me to help them. Those that already know all the answers, or display that attitude, rarely learn as much as those assume they know little.
  3. Enthusiastic. My favorite students are fun to work with. Positive and negative attitudes are infectious. When the student is having fun, I’m having fun. What’s more fun than seeing a student take pride in learning a new skill?
  4. Brave. I like students who overcome their fears. Bravery isn’t the absence of fear, it’s performing while scared (or at least anxious). Driving a car fast is dangerous, and that danger creates some fear. Sharing in a student’s triumph over fear is truly special. Every time.
  5. Inquisitive. I don’t simply mean asking questions. Anyone can ask “what’s your line through turn 3?” What I prefer is to hear comments that show they’re asking and answering their own questions. Ultimately, every driver has to teach themselves. If I hear “sorry, I messed up that corner, but I was trying to carry more momentum” I know they were thinking.
  6. Simmer. I can always tell when a student has had a lot of simulator experience. Their bodies are sometimes ahead of their minds. That is, the sim has trained some of their muscle memory but their brains haven’t yet connected the virtual and real worlds. It’s fun when the students are surprised by their own abilities.

So I guess that begs the question of the worst student… well, I wouldn’t want to be in the passenger seat with this guy.

https://vid.me/xlOb#2m30s

Data Analysis: Thompson

Last week I wrote about the ChumpCar race at Thompson. This week I want to take a look at the telemetry we recorded with an Aim Solo. As a reminder, this is what the track looks like.

The first thing I want to explore was the difference between my practice and the race. My fastest race lap was more than 2 seconds faster than my practice. Why was that?

The top panel is speed. The next two are G-forces. The bottom is time difference. I don’t tend to find the G-force graphs very useful.The black line is the “reference” or fast lap. The red line is the practice lap.

If you look at the speed graph, you can see that I’m pretty much faster everywhere. I’m braking deeper into the corners, and I sometimes have lower speeds in the middle of the corner (actually slightly before the apex). I knew when I was driving my fast lap that I had pushed too hard at point A and was understeering badly. This turned out to cost me about a tenth, so it wasn’t that bad. In order to get into the 1:26s, I’ll have to find more speed. So let’s look at the other drivers to see what I can learn from them.

I brake later and carry that speed much farther into the corner. By the time I’m on the gas, I’ve gained over a second on the green and red drivers. But I’m much later getting on the gas, and that advantage starts to decay. If there was a long straight following T1/T2, they would catch and pass me. However, on this track, my strategy would allow me to pass them going into T1 and block them on the way to T3. I brake later and keep more speed through T3.

Despite my more aggressive driving style, I’m no faster than the blue driver, and the red driver has mostly caught me by the time we fully exit T4. At some point I’m going to gap them by 2 seconds, but it isn’t through these slow corners. T5 has a funny data error; ignore that. I brake much, much later in T5 and carry the same exit speed. So I put some distance between myself and the red/green drivers. But the blue driver has a similar line to mine and we’re still neck-n-neck as we head toward the bowl.

In T6, you can see that I have the lowest mid-corner speed. I took a lot of different lines through here and this one wasn’t that good! By the time we are running down the straight between T6 and T7, I’m not much ahead of the red or blue drivers. What happens next is critical.

The red and green drivers brake much earlier. They have a somewhat constant rate of deceleration all the way to T8 and then pick up throttle from there. Without a throttle or brake trace it’s hard to say if they are coasting, but my bet is that after some initial braking, they are scrubbing speed by coasting. Coasting is generally not the fast way around the track, but it does have its uses. In contrast, the blue and black drivers have a roller-coaster speed trace. They brake much later on the way to T7 and speed up between T7 and T8.

The blue driver is losing nearly 2 seconds by overspeeding between T7 and T8. He ends up turning T8 into a braking zone. His speed never recovers and he ends up with the slowest speed down the main straight. This is a Miata, not an M3. The throttle is a suggestion to go faster. You have to keep as much speed as possible, especially in the fast corners.

Thinking back to last week, I was really excited about this series of corners. It’s a Type II followed shortly after by a Type I. That is, you brake way late for T7 to keep as much speed as possible. Then you throw away the exit to set up for T8 with just enough speed that you’re full throttle from just before the apex until the end of the main straight. That’s what I did, and it’s 2 seconds faster than the other drivers. That said, even if the others had taken my same line, they are unnecessarily lifting or braking to set up T9. That section is really about confidence more than technique. They’ll get faster as they get more laps.

3rd Gear Experiment

Late in the day we started losing the clutch. So Mario decided to do an entire stint without using 2nd gear. The results are pretty surprising.

The black line is his reference lap (fastest 2nd gear lap). There are two 2nd gear corners: T1 and T4. Once you hit T5, it’s 3rd and 4th all the way. So let’s look at the time and speed through T4. Amazingly, the loss is only 0.2-0.3 sec. In T1, he consciously holds more speed in 3rd gear. While he doesn’t get as much drive leaving the corner, he loses no time to shifting. The net effect is that he has lost no time by the time he hits T3. He does lose a couple tenths in T4 though. It’s a really tight corner, and 2nd gear puts the power down much better than 3rd. But it’s just a couple tenths. OK, so I’m driving in 3rd next year, at least in T1.

GPS Alignment Issues?

One of the YSAR readers, Sten, who happens to be a data analysis professional, claims that “some of the data is definitely misaligned”. I admit that I suck at telemetry  analysis, so I followed up with him. Over email he further specified that it was impossible for the black and green lines to be accurate in T1 and T3, for example. Here’s an overlay showing the 5 fastest laps from the black and green drivers. They are fairly consistent.

Race Report: Thompson

This weekend, I raced in a 12 hour ChumpCar race at Thompson Speedway Motorsports Park with my twin brother’s car on team “Occam’s Racer”.

With the exception of Thunderhill, every time I’ve driven a track, I’ve practiced it first in simulation. The Thompson Speedway road course isn’t in any simulation. So that changed how I approached the learning process. In simulation, my first sessions are driven very hard. My primary goal is to catalog the dangerous parts of the course. A violent wreck tends to stick in my mind. Obviously, that isn’t my plan in real life! What follows below is sort of a journal of how I prepared, practiced, and drove in the race.

Part 1: Pre-race Preparation

I’m watching about 7 videos. Some are races and others HPDE sessions. A few are really good and worth watching multiple times. I’ve got a track map that I’m marking up. The first priority is always to find the flag stations. For the most part, these are line-of-sight, low, and near the middle  of corners. The exceptions are T3, which is elevated, T5, which is on the backside of the turn after the bridge, and T10, which becomes visible on the inside as you approach the exit. Making a mental note of the flag stations will be the first thing I do when I go live. Here are my initial thoughts on the turns.

T1/T2 – Reminds me a bit of Summit Point. Starts very slow and then increases in radius as a single corner. 2nd gear shifts to 3rd in T2. Get the braking and turning done early and turn this into one long opening corner.

T3 – Still Summit-like with a slightly early apex 90° that goes a little off camber and blind at the exit. Reminds me a little of Willow Springs T1.

T4 – Tightest corner on track. 2nd gear 180° hairpin. HPDE line is late apex, but I think going around the inside will work better in a race (more defensive, keep speed longer, following straight isn’t very long).

T5 – Another 180° but slightly faster. Seems that one could go late apex, double apex, or tight. I feel like double apex is the default. There is some straight following, but not enough to prioritize exit speed over position.

T6 – An even larger 180°. A single late apex is expected as there is some straight afterward, but I suspect going around the inside is going to happen more often than not in a race. The track out gets close to the wall only at the very end.

T7/T8/T9 – The most interesting sequence of the track. T9 is critical because it sets up the main straight. If the car isn’t at the limit in T9, it means that T8 or T7 were messed up. The approach to T7 is to let the car create space as it passes the wall on the left. Trail-brake around and completely sacrifice the exit. The key is to get the car parallel with the curbing for the T8 entry. Straighten out T8 as much as possible and get on gas as early as possible. Start building speed before the T8 apex and keep building it. Track all the way out and stay out to set up T9. Diving too early into T9 will require lifting at the exit, which will kill the top speed. This whole section requires some discipline to get right. I’m really looking forward to this sequence.

T10 – Not really a turn, but the start of the main straight.

Part 2: Friday Practice

I just did 12 practice laps. I feel like that was enough to get a good idea of how to race it. In person, the track feels really different from what I saw on video. There’s more elevation than it would appear and there are several changes in camber. Also, the surface doesn’t have as much grip as I expected. My first 4 lap times were: 2:10 (out lap), 1:35, 1:32, 1:30, 1:29. It turned out that 1:30.09 was my median race lap, so it only took me 3-4 laps to get up to race speed.

Here’s my post-practice download.

T1-T2 – Brake between the 4 and 3 marker. There’s positive camber here, so grip is good. It turns downhill halfway through, so you really can’t hold trail-braking around or the car will over-rotate. Better to get shit done (braking, turning) early and then add throttle to stabilize the rear.

T3 – I didn’t do this corner correctly even once. It’s just a 90° left. Oddly, I sometimes thought it was T5, and went in thinking I was going to double apex it. I’m mad at myself for not finding the right reference points for this. On race day, I’ll have to make sure I focus on this corner.

T4 – It’s as tight as expected. It drops in elevation toward the end similar to T1, and it’s also important to get shit done early. There’s some throttle modulation required to maximize traction.

T5 – Indeed, this is a double apex. I saw a lot of cars throwing away time trying to enter too wide. The angle at the 2nd apex is critical to get right as the wrong angle could send you off track. I may try to go a little deeper tomorrow to get a better run into the 2nd apex.

T6 – A bit of a puzzle. It definitely felt faster going wide at the entry. But I also found I could put some distance on other cars going in tight. Maybe it doesn’t matter.

T7 – This is one of the best examples of a Type II corner I’ve ever experienced. I brake very late and totally sacrifice the exit. It’s a good passing zone as timid drivers will dawdle on the right side. Brake AFTER the ripples in the track.

T8 – I’m on the gas before the apex, and I feel that I should be able to commit to 100% throttle even sooner. Something to work on.

T9 – Message to self: 100% throttle the whole damn time. Commit to it.

Part 3: Mental Imagery

Mental Imagery (MI) is Ross Bentley’s thing. I generally don’t do that much (sorry Ross) because I find that simulation fits me better. But of course I don’t have Thompson Speedway in any sim. So time to do some MI. To get myself in the mood, I’m going to queue up some helmet cam footage I took during the practice session (helmet cameras are not allowed during the race but I didn’t hear anything about no cameras in the practice session…).

Part 4: Endurance Race

The race did not start well. On the opening lap, my brother Mario said “just let that guy by” as we watched an overzealous BMW e30 bullying his way through the first couple corners. About a minute later, our car comes into the pit dragging part of its diffuser. The driver, Patrick, had to dodge the BMW when it spun in front of him, and the subsequent trip into the grass yanked on the leading edge of the diffuser. Then the pit marshal came over and told us our transponder wasn’t working. So we had to make 2 minor fixes before completing even a single lap. On the plus side, the demeanor of the team became more relaxed as we had already lost the race. Now we could drive unencumbered with the thought of winning our class.

Patrick put down a lot of solid laps with a few times in the 1:29s. I got in next and started a string of 1:30s and a few 1:29s. I thought to myself “I think I’ve got a high 1:28 in me”, but it wasn’t until the end of the session that I did any. For most of the race, I was content to hook up with a car making a decent pace. At one point this was the Ztech Racing Honda Accord. Later it was an RX-7 that had the misfortune of smashing through a tire wall during the first hour. The corners where I made up the most time were the double apex T5 and the T7-8-9 combo. I often got enough speed out of the last section that I could stay in the draft of the higher HP cars down the main straight.

It took me a while to figure out how to optimize the 2nd gear corners and also the bowl (T6). But once I did, my lap times were dropping even though I was still driving conservatively. I got a couple 1:28s hit traffic, and then did more. After one really good T1 I decided to go for a flyer and see what I could do. Although I scrubbed too much speed understeering through the last corner and had no cars to draft, I produced a 1:27.29. I’m sure I could do a high 1:26 given another session, but I was running low on fuel and wanted to do some short-shifting laps to see what I could do without ever using 2nd gear. 1:29.59. I should have done that experiment earlier in the day because I probably would have driven it that way instead. Yes, it’s a little slower, but it’s easier on me and the car not to shift so much.

When we refueled the car, it only took 10 gallons. So despite the fuel gauge reading empty, there was still a few gallons left. In a 12 hour race, ideally we would run 6 two-hour stints. So only 5 pit stops. But due to the fuel gauge and cockpit heat (no cool suit), we ended up doing 8 pit stops. With the 5 minute pit stop rule, we lost 15 minutes or 10 laps. And the problems at the start of the race cost us another 4 laps. Ah, to have those 14 laps… Alas, we ended up in 11th place (9th if you discount the EC class cars that aren’t playing by the same rules).

Part 5: Post-race Thoughts

Car: The car was great. There was 1 Miata that was faster and 4 that were slower. The Occam’s Racer Miata was a Spec Miata in a former life and is still carrying at least 100 lbs of extra weight. So there’s some free performance improvements expected down the line. We ran Dunlop ZIIs in 205/50/15 at 40 psi hot. That’s maybe too high for such a twisty track. ZIIs are also not the fastest of the 200 treadwear tires. Not sure if we could get RE-71Rs to last 12 hours though. If we wanted to spend money, we could definitely get more power out of the motor, which is currently just a junkyard replacement. With Occam’s Racer not due on track again until Spring 2018, there’s some time to sort things out.

Track: Thompson Speedway is a really great track. With the exception of the main straight, there is very little breathing room between corners. That makes passing more difficult and more fun. The various small changes in elevation and camber are a challenge to optimize. I can’t wait to return. My small complaint about the track is that it’s a little bit one-note. Long corner, short straight, repeat. There aren’t many puzzles to solve. So the thinker in me was happy when there was traffic to work around. The event drew 38 cars, which is enough to make things interesting, but I would have preferred 50-60.

Racecast: We need to sort out the Racecast camera. We were supposed to be streaming live the whole day but I don’t think it worked at all. Unfortunately, no race footage from our car.

Event: The ChumpCar staff did a great job organizing the event. I wish they had run a few more warmup laps. They didn’t notice our transponder wasn’t pinging until after the race was underway. The Friday practice was not well organized. From the long line-up outside the gate to the practice session that started over 90 minutes late, it was a shit-show most of the day. Fortunately, they have good onsite food.

My Driving: For the most part, I was happy with my driving. I was particularly pleased that I was up to race pace on my 4th practice lap. I did my homework preparing ahead of time and it showed. In the race, I didn’t make contact with any cars, go 2 wheels (or more) off, or lose control of the vehicle. I raced within my abilities and managed to set fast time on the team by 2 seconds. Time to put another track decal on my windshield.