Coolant

[Atrosity]

For racing applications/hot weather, which is the most optimal coolant fluids do you prefer?

[mb3000]

Engine Ice.

[Maximal]

Personally I think that the coolant system itself (radiator, ducting, clean system) is more important than what's inside it. A mostly water mixture with a bit of coolant for lubrication works well with me. Of course I have a koyo radiator, a freshly flushed system, ducting around my FMIC/Radiator, and a high pressure cap.

[Lithium]

cooling systems are simple, Pure water dissipates heat the fastest but also has a low boiling point. anti-freeze lubricates and raises the boiling temp of the cooling system. 50/50 of just about anything will do just fine. Whatever you do make sure you have plenty of anti-freeze in your system if you live in a cold area.

[RealMcCoy]

I prefer the standard 50/50 mix in most cases... We used to run straight water in the drag cars, simply because you would be very unpopular if you overheated your car and puked anti-freeze all over the track. Water was pretty easy to dry up.

[GTOX]

I'm using some Redline water wetter atm with my coolant...

[DocWalt]

I've always run 50/50. If you plan on taking it to the strip, they may be very picky (for good reason). Test n Tune nights they were more concerned with people leaving their A/C on than they were with antifreeze...

[cjbyron]

For racing applications/hot weather, which is the most optimal coolant fluids do you prefer?

For racing only applications the most optimal coolant fluid is water. Use distilled water (to avoid minerals, etc. from tap water). A little Redline water wetter helps too (it does work). While straight water has lower boiling point your pressurized system also raises the boiling point. If it is extremely hot weather and worried about boil over (as in your car cannot maintain proper coolant system temps) you can add in 10-20% Ethylene Glycol to raise it. Some tracks will not accept even that % though. Check with the track you will be running for their rules. 50/50 is way overkill just for racing applications. While it will give you very high boil-over protection and protection from freezing in the arctic (neither of which is applicable here, i.e. - racing) it will drastically reduce the cooling abilities overall. IOW - your system will actually operate hotter.

IMO if your cooling system in a race application cannot keep your engine in the temp ranges you need then make changes to improve your cooling system rather than compensate by adding 50% antifreeze. That would be the right way to address it. This way too the rest of the people at your track aren't sitting around for hours waiting for the track to be cleaned up after the radiator hose blows (or whatever) lol.

[i3igpete]

i would at least use 10%. coolant passage corrosion kills the block's ability to cool itself.

[cjbyron]

I can agree with the need to have some corrosion protection. Definately.

Redline Water Wetter provides all that and tested/proven over the years in race vehicles
Red Line Synthetic Oil - Water Wetter® Coolant Additives - Water Wetter®

Some folks even swear by other things like a small dose of water soluble oil into pure water, etc.
But many (most?) seem to prefer distilled water and added waterwetter. At least those I know.

And if your local track says no antifreeze then that means no antifreeze. It isn't a choice.