Keeping cool

[LennyM1984]

Without going to the extreme of a water cooling system, how are people staying cool beneath their race suit? My car is cramped, has no AC, and is made.of fibreglass. As such it gets uncomfortably hot in the cabin on a warm day.

I've seen t-shirts that you soak in water but I assume they'd just create a soggy and even sweatier suit.

So what "solutions" have people found?