[Honda100]

For reference, an LT1 water pump is around 32-36 GPM.

The thing is though, yes I understand the intrigue, but it's not really worth it. At full tilt, a 36 GPM water pump is using maybe 1 hp, and that's for a 5.3 liter V8. Let's say the Corolla is the same though (I have a Corolla and I know the pump is considerably small than an LT1, but let's just say). Anyway, I have a 400 GPM water pump at my farm and it uses an 11 hp motor to drive it. Assuming the diesel isn't 100% efficient, it's probably using just 8 hp to crank a 400 GPM water pump. So that's less than 1 hp per 40 GPM. If the Corolla had a 40 GPM pump (which it doesn't), then at most it is using 1 hp to drive it at full throttle. That's less than 1% of it's available power at full throttle. At idle, it's significantly less obviously, so you're likely looking at a tenth or even half of a tenth of a horsepower most of the time.

So, in essence, it's not going to gain you anything.

Also to note, in Cambodia (where it's always 90 plus degrees, sometimes 100), my Hyundai runs with the A/C on full blast in the city at idle (stop and go traffic all the time) and it never goes over 190 F. I just use distilled water and water wetter with a 20% antifreeze mix. Never had an issue with the heat, so I wouldn't worry about it.