Race cars are always heavily modified (compared to the road going versions). They must have upgraded the cooling system to allow for sustained high loads.

Depending on the car, not as much as you'd think.

My mechanic has been a mechanic for both IMSA and World Cup Challenge teams, and he went over some of the changes that are seen from road-going versions of what he normally works on (Porsches). Things like heat exchangers have better conductive materials, coolant lines will make multiple passes instead of a single pass, and there are more lines (to increase the surface area of the line), packed in more densely. Coolants used are optimized for a specific temperature range, since they don't have to deal with global conditions of a road car all over the world.

More complex machining for passive cooling (heatsinks) of transaxles, higher airflow towards brake rotors (with specific shield designs, part of which are backed out to catch more air).

The biggest change? Fewer fans, and only as many as required, as they inhibit airflow. Convection does the job well enough as race cars aren't sitting in traffic in hot climates, and aren't sitting around long enough to heat soak from being stationary (but are why the pit crews have blowers). As much aero design goes into routing air for maximizing cooling as there is for creating downforce.

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Formula 1 and WEC (which are more like ground aircraft than anything resembling a road car) are a different story though. Things like the intercoolers for turbochargers are absurdly complex. You're talking four passes through the intercooler, and lines that are basically long surgical needles, with ~13000 packed into each intercooler. All hand built, all very expensive.

So how much exactly energy is lost to battery heating in Tesla? Quite a lot if a liquid cooling system is unable to deal with the heat?

not really, but it depends on the class. A gt3cup car has a boatload of changes. Race-built engines, different suspension, etc. gt4s are closer to the stock car. TC even more so.

I was surprised to learn about the 2018 Dodge Demon's SRT power chiller. It uses the car's refrigerant to cool down the supercharger. On race day you actually have to turn off your AC. The whole car is insane, especially considering that it is street legal and may of its owners will be using it as a daily driver.

That's an idea that dates back quite a ways. Ford had a prototype F150 Lightning that used A/C to temporarily cool down the intercooler and gain something like 30-50 horsepower for around 30 seconds at a time. Unfortunately Ford elected instead to just kill the Lightning altogether at that point.

Great idea, surprised I haven't seen this as a street legal mod.

You would only need to sandwich the intercooler between the hot and cold heat exchangers with a (fairly powerful) automotive refrigerant pump connect to them. The cold heat exchanger would go in front of the intercooler.

I'm going to start talking about this to some enthusiasts I know and see if I can convince one of them to do it.

>> Great idea, surprised I haven't seen this as a street legal mod.

It was a homebrew hack by people in the Honda Civic / del Sol community decades ago, I recall it fondly.

How many owners are going to be swapping between the drag radials/skinny front wheels and daily driver tires? Or willing to deal with the mileage?

That's nothing new, my Jaguar XJ12 from '84 uses it's AC to cool down the fuel in the return line.

They will also need to take off a lot of weight from P100D's 4,941 lbs to make it worthwhile. Even they can reduce the weight by 1000 lbs, it'll still be very heavy... It's a luxury car with a powerful engine - not exactly what you'd want for racing.

It won't be the first grand touring race series by a long shot. Racing series are always contrived, with rules to make cars equal and most cars ended up almost 0% like the factory model.

They'll just create weight classes as they expand beyond the Model S. People are very happy to race heavy vehicles[1].

https://www.youtube.com/watch?v=ZUgw2GcXQUM

There are additional issues due to the heavy weight on the track - the brakes and the tires will get used up much faster for example.

.. and on a circuit... https://youtu.be/6AqeqeSdH94?t=2m31s

One of the points of racing is to find out creative solutions to such engineering problems, which may later filter down to road vehicles. Example of technologies which had their origin in formula 1 include traction control, KERS, automated manual transmissions.

>racing such a computer-controlled car without a good way to interface with them seems untenable.

Seems like a nice challenge for the hacking community, and again racing might provide the right narrow focus and motivation to get the job done.