Spraying Autocross Tires...
 

Does anyone have any data to support this being beneficial? I see guys doing it, but my mechanical engineer brain says there is just not enough mass in that water spray to do jack diddly squat. You might cool off about 1 micron of rubber on the surface, but inside the tire is not going to cool down at all.

Yes, it makes a difference. GRM includes before/after spraying results, with a control, in some of their tire test articles. Not all tires benefit from it.

I used to do it with my Focus ST on RE71R, but that used to melt front tires on hot days. With the Camaro on Rivals though, I don't see the point. The tires like heat and the Camaro isn't heavy enough or a torquey FWD car.

Another factor is the crowd you're in. I've felt dorky when I'm the only person at the event spraying tires. But, if you have a series of back-to-back runs on a hot day with tires that don't work well hot, spraying can make a big difference. Using a pyrometer, I have observed tires drop a lot more degrees with spraying than without. The mass of the sprayed water may be very little compared to the tire's weight, but water absorbs a lot of energy when it evaporates (or when it melts). Think about how refreshing a spray of water is when you're overheated.

Sweating works, works on tires too! It works mostly by heat of vaporization, water absorbs a lot of heat changing state from liquid to gas as Roostie mentioned.

If you think about it, autox is about 1 min long, all heat is generated at the surface of the tire so if you spray right after a run you're hitting the hottest part of the tire and preventing the heat from absorbing further into the tire. Might not always work out ideally but it certainly works to some degree.

I just want to highlight the rare opportunity here to say, "the Camaro isn't heavy enough." :smiling1: Most of the time it's quite the opposite!

I was thinking the opposite. Unless you have back to back runs the OEM SC3s seem like they need more heat. RE71Rs come in quick. I was thinking to use covers for nearly most of the year.
Anyone in a 1LE check tire temps in summer? Or at least look at the car tire temp display and see "warm" after runs?

I looked last event in March when it was 85 out. Re71s just read normal. But normal is a wide range I read.

If you're on a set of RE-71's and you make a run, right after you're done place your palm on the tire. If its hot enough that you're uncomfortable keeping your hand on it, you had better spray them down before your next run.

I mean, the 2.0T comes in at just over 3300 lbs with a full tank of gas, which spread that out over some 305s, and it's not terribly heavy per square inch of contact patch.

Thanks for the input. Now I'm going to do some math, brb. :)

Yeah, so far only hot after third and last run. And wasn’t that hot. 140 degrees about tops temp wise, and you feel that! That’s on a 95 degree day. On Bfgs don’t bother spraying. Bfg says don’t do it till you hit 190!

PS I have RT660's coming Friday. Last summer I ran the stock SC3's and had my best days when it was over 100. RE71R guys were all spraying and I was sitting in the car with the AC on listening to tunes. :D

Yup, I'm going for RT660s 315/18. I had the same experience with the SC3s, they heat up too slowly and don't give best performance unless it's hot and sunny. I feel a couple races were a waste of time because the tires never warmed up.