Tracking car hard in hot climate

[bigjae46]

Driver407 OP, did you ever figure out a solution to get through these hot track days? I haven't thrown any money at my car this year but I'm in NorCal as well. Thunderhill and Laguna Seca with ambient temps outside above 90 degrees and my coolant needle will touch red (if I redline). Even does it in the canyons if I'm really sending it. I basically just don't go to the track from June to October. Water wetter alone did absolutely nothing for this heat we've been having this year.

My plan before dumping $1k into a complete refresh is to flush all the old coolant out and do straight distilled water + water wetter and seeing how it goes.

Coolant doesn't do much cooling if any. Its main purpose is to lower the freezing point of the coolant/water mix and to lubricate the water pump. So distilled water will work a little better but won't be transformative. If you do use distilled water...use water wetter. I'd dump the entire bottle in. The bearing on the water pump needs a little lubrication. Water provides none. Water wetter will help a little but it is better than nothing.

Side note, I saw a facebook ad for some pressure washer attachment to clean radiators in the car. Wonder if a pressure washer would totally destroy the fins? I use compressed air and then a compressed air sprayer to blow out coolers. It works ok but still leaves stuff in the fins.

[Obioban]

Water wetter also leaves deposits, so every day you use it your entire cooling system gets slightly less efficient.

[MTiz]

Coolant doesn't do much cooling if any. Its main purpose is to lower the freezing point of the coolant/water mix and to lubricate the water pump. So distilled water will work a little better but won't be transformative. If you do use distilled water...use water wetter. I'd dump the entire bottle in. The bearing on the water pump needs a little lubrication. Water provides none. Water wetter will help a little but it is better than nothing.

Side note, I saw a facebook ad for some pressure washer attachment to clean radiators in the car. Wonder if a pressure washer would totally destroy the fins? I use compressed air and then a compressed air sprayer to blow out coolers. It works ok but still leaves stuff in the fins.

Yeah it's kind of annoying to deal with. When it's 90+ degrees outside I just don't go crazy shifting all the way at redline. And when it's 100+ I just leave the car at home and drive the F80.

[Driver407]

Another cooling performance check-in:

Was out at Thunderhill East this weekend in 100* heat. The final test for the revamped cooling setup. (D088 rad/oil cooler; new thermostat, waterpump, 30/70 coolant, water wetter)
Ran two groups back-to-back (40 minutes) across the day.

By session 4 the coolant dashboard gauge was starting to hit the dot. So I pulled off and hooked up my OBD reader to monitor temps accurately.
From that point on. The highest temps reported by the ECT coolant sensor ended up being 216. Shifting at redline and not babying anything.
Oil was never a concern at all. It never crossed the second dot and lived within the ~230-255 degree zone the entire day.

Doesnt seem like I need to go down the path of adding hood vents. Which look great in addition to function but I am not really wanting to permanently alter my hood at the current time.

Still had to do cooldown laps across the day for my tires tho (RE71RS). They definitely cant go 40 minutes non-stop. Let alone 20.
Ended up basically matching my existing personal best in the E46, .05 slower. 2:02.83.

At this point I am confident recommending this setup as the answer to tracking in extreme heat. Couldnt really push the car any harder and it was not breaking a sweat.

Here is the track day footage. From 38 minutes onward. I have the OBD reader up on my headunit. The ECT coolant temps are shown directly below the catalyst on the right side of the screen. For reference.