Some race tracks are power tracks, and some are grip tracks. At the extreme ends of the spectrum, compare a salt flat to a skid pad. On the salt flat, there’s no cornering, it’s all about power. Likewise, on a skid pad, it doesn’t matter how much power you have, it’s all about grip.
However, you also have to consider the aerodynamic factors of drag and lift. On a salt flat, drag could be a huge factor. On a large diameter skid pad, aerodynamic lift (downforce), could also weigh heavily (pun intended).
Most race tracks are neither salt flats nor skid pads, but somewhere in between. Some favor grip, some power, and some aero. I thought it would be interesting to run a bunch of simulations in OptimumLap to find out which tracks favor power, grip, or aero.
For the simulator car I used a Miata (surprise!) with 100 hp, 2400 lbs, tires at 1.0g grip, andvCd 0.5, Cl 0.5. These are very low, round numbers, meant only to illustrate the differences. Moreover, the low power and grip values create larger gaps in the data, which makes it more obvious which tracks favor which attributes.
I ran this base car on 12 different race tracks that range from an autocross course to the fastest closed-course race tracks in the USA. There’s a good mix of tracks in OptimumLap, but I also added the map my brother made of New York Safety Track, because it’s local and awesome.
After the initial base simulation run, I then added 10% grip and re-ran the group. The lap times dropped across the board (especially at the autocross course), and I logged the data.
I then removed the additional grip and added 10% more power. So at this point, we’re back to the base car, this time with 110 hp instead of 100. Lap times fell again, but not always in the same order.
Finally, I removed the extra power and changed the coefficient of lift from -0.5 to +0.1. This is not a drastic change, one could easily get this from an airdam and small spoiler. I left the drag (Cd) the same, as it probably wouldn’t change much (it would actually have less drag, but I chose to concentrate only on downforce).
The table below shows the base lap time, and then what happens when I added more power, more grip, and minor aero. I ordered the table by tracks that favor power at the top, in the middle are tracks that favor aero, and at the bottom of the table are the tracks that favor grip.
|Watkins Glen||157.30||155.33||154.97||154.97||Power and Aero|
|Thunderhill||142.71||140.60||140.74||140.59||Aero and Grip|
Race tracks with long straights favor power, and so it’s not surprising to see VIR and Mid-Ohio at the top of the list. Likewise, an autocross course, or a smaller technical track like Waterford, are grip tracks. Finally, some tracks are fast and flowing, and suit aero.
Not every track was definitively a power, grip, or aero track; some tracks are a mix of two. Watkins Glen favors both power and aero, while Thunderhill (3 mile) favors grip and aero.
I then re-ran the simulations using a Miata in a higher state of tune. I left the weight the same, but gave it 120 whp and 1.2g grip, to see if the relationships would change at all. Nope, they stayed the same. Astute readers will cite that a high-power car like a Corvette rarely benefits from more power at any track. But this isn’t a site about Corvettes….
Note: As I stated earlier, the coefficient of lift value (Cl) for the aero car is 0.1, which is pretty low. A Miata with an airdam, splitter, and wing has a Cl of 1.0, which is way better. If I re-ran all the simulations using that value, then it would show that every track is an aero track, and that wouldn’t tell me much about the nature of the track. So I purposely chose a low Cl value that would illustrate which tracks are more favorable to power and grip, and put the aero into equal perspective.