The Cone Geek

 After trying autocross, I was back. Now, I needed to get better. For this event, I had two goals; the first one was to improve my driving. I wanted to get a video of my hands during a run. I don’t have data to track my steering angle, so this is the next best thing. I invited a passenger to run with me and record me while I drove. The second one was to start trying to understand the tires. For this, I bought a tire pressure gauge and a temperature sensor. Racing sensors were too expensive, so I got a generic one off of Amazon. This one has a probe that you can pinch the tire with, as well as an IR measurement tool. In this event, I used the IR. I also made a change in my driving; by looking at the speeds from the previous event, I realized that through the whole track, I was within the powerband for second gear, so after launching, I shifted into second and completed the runs in second. I am now having doubts about that strategy (based on my Optimum Lap simulations that show tha...

  After being away from participating in motorsport for more than 5 years, I gave myself the purpose to participate in some form of motorsport as a 2024 new year’s resolution. But on a startup entrepreneur’s budget, racing in something where I shared a track with other people, even karting was out of the question. After a lot of research, I found that autocross is a great option to enjoy racing in my daily driver Dodge Challenger. The speeds are not that high, and the spaces are open, so when you screw up, which will eventually happen, there is a lower risk of expensive damage. There are different classes so that you don’t have to have a highly tuned car to compete and honestly, it looks like a good time. That’s why I decided to sign up for the June 23rd Autocross. It was a two-day event, but I could only race on Sunday due to a family commitment. I found that the Central Florida Region has a few events every summer, so this was perfect. To be honest I was scared, I had never be...

  Now that I have my local course and my car on Optimum Lap, I can use a very cool feature that it has called batch run. Basically, you can, keeping all other things equal vary one parameter of the car model through a range of values. This will help us understand where the biggest gains are hidden. You can see the tires hard at work on this photo from the August Daytona SCCA Solo CFR event. The first parameter I decided to vary was the weight of the car. I did a sweep from 3600 to about 4500 lbs. What I found is that reducing the car weight by 400lbs will bring about .2s worth of time. Also, I could answer something that always makes me curious, what is the penalty for carrying a passenger? Let’s say the person is 200lbs, In my car today, this will be a 0.2s penalty. So once I have my technique together and don't need an instructor I will run alone. We can see that below a certain point the improvement from making the car lighter tapers off as we struggle to put the power to the...

  The next step in getting the simulations running is building a digital model of the SS Conegeek, the name to no surprise is because sometimes, on an autocross course, the Challenger SXT will feel more like a boat than a car. For this, if you have scales and actual dyno plots from your car you will get a very accurate model. Since my car is stock, I mainly used the information available online to build this.  Photo of the SS Conegeek in Daytona, taken from CFR SCCA Autocross Facebook group. The first step is obtaining a power curve. Optimum lap allows for multiple unit systems to be used, but in reality, anything other than metric is clunky to use, so get your calculator out. I found this curve online for the 2021 Challenger SXT with the Pentastar V6, which shows a maximum power of 305hp at 6350 rpm and a peak torque of 363Nm at 4800 rpm . You also need the car’s weight, drag coefficient, frontal area, and the size of the tires you’re using.  We estimate the car’s dow...

  The first track I created in Optimum Lap was the Daytona Kart track layout as raced on August 3rd, 2024. My Second Autocross. I decided to use this course as it is my local course and where I am going to do most of my racing (Having a toddler makes traveling for races difficult).  The first thing I need to say is that making the track incredibly accurate and making sure laptimes correlate to the thousandth of a second is not the goal here. The objective is to get a track that will provide similar behavior to the cars on the course and where the sensibility of the car to different changes and mods can be evaluated. We can also evaluate some of the techniques the optimum driver uses and find potential areas where time can be gained.  The approach I chose was simple: I took a snapshot of the track on Google Maps' satellite view with the highest zoom I could. I also made sure that the scale was visible in the screenshot. I then imported the course into Autodesk Fusion. F...

Here’s a real scenario: You’re new to autocross and want to make your car faster (just like everyone else on the track). You start talking to people in the paddock about modifications; everyone has opinions and recommendations. You start visiting different forums; everyone has their opinion there. You choose who you believe and spend a lot of your hard-earned money on the next mega gadget. And go to the track and your car is undrivable. As racers we need tools that allow us to make these decisions with more certainty than what someone else said. Laptime simulation is a great tool for understanding how a racecar will behave on a specific track. There are many different options for Laptime Simulation, starting with simple simulations that can be created in Excel and going to the full bespoke programs that professional race teams use at the highest echelons of racing to predict the car's setup on a specific circuit when limited training time is available. The concept is, what if an ...