Tracking car hard in hot climate

[dreamdrivedrift]

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.

Glad DO88 is working out
We prob have similar comps so I'll update my OE-ish experience

OE-ish setup - new OE rad, 60/40 split + water wetter, old OE oil cooler, AC condenser, NO pusher, SPAL puller.
I use the OBD to track water temps

At Laguna in November, mid 70s, 1:43 pace on RS4s. The car got 10 min or so without overheating at full tilt 8K shifts, then starts creeping water temps to mid high 210s. I'll usually I back it off and shift early and it comes back down, haven't kept pushing to see if it'll 220+. But, the car did 60 minutes at a time with back to back drivers throughout the afternoon and took it like a champ.
At Thunderhill East, in May, I recall it being pretty warm prob mid 80s. Full push - 20 min sessions, 2:02 pace on RS4, zero issue. Did not have to back off at all. I think avg speed might be a bit higher at thunderhill east, better for cooling.

[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.

[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.

[Obioban]

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

[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]

I hate water wetter.

[MTiz]

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.

[bigjae46]

I thought this as well. When I was refreshing cooling system I tried both.

With just the clutch puller fan and shroud at idle and AC on the car would overheat.

Putting the pusher fan back on and removing puller I could run AC all day at idle and temps were stable.

Given that 90% of my use of the AC is sitting on grid id rather not overheat before going out for a session.

I know coolshirt is the real answer but not ready to make that jump yet.

I would just put a high output fan on the back of the radiator and call it the day. It will overcool at idle.

[eacmen]

If you have the AC condenser you really need a puller fan more than the pusher fan.

I thought this as well. When I was refreshing cooling system I tried both.

With just the clutch puller fan and shroud at idle and AC on the car would overheat.

Putting the pusher fan back on and removing puller I could run AC all day at idle and temps were stable.

Given that 90% of my use of the AC is sitting on grid id rather not overheat before going out for a session.

I know coolshirt is the real answer but not ready to make that jump yet.

[bigjae46]

Everything is fresh OE excluding the shroud and puller fan. That could explain the coolant temps but not so much the oil temps.

I do have the bimmerworld front splitter on the car. The AOA isn't ideal but maybe that could be starving the airflow over the coolers.

My issue is that this July event is the only one each year where i really stress the cooling. Every other event its a non issue.

If you have the AC condenser you really need a puller fan more than the pusher fan.

[eacmen]

I would refresh your cooling system with OE parts and blow out the fins on your oil cooler and AC condenser.

Honestly, the E46 M3 has a rather robust cooling design.

Everything is fresh OE excluding the shroud and puller fan. That could explain the coolant temps but not so much the oil temps.

I do have the bimmerworld front splitter on the car. The AOA isn't ideal but maybe that could be starving the airflow over the coolers.

My issue is that this July event is the only one each year where i really stress the cooling. Every other event its a non issue.

[BCEXP]

I would refresh your cooling system with OE parts and blow out the fins on your oil cooler and AC condenser.

Honestly, the E46 M3 has a rather robust cooling design.

[Estoril]

Were you at the NJ CCA event? I was there as well. My coolant temps were getting up to 220 and oil temps were getting up to 275.

I had to do cool down laps mid session.

I still have A/C with pusher fan. No puller fan. I used to have the CSF rad and just running A/C car would overheat at idle. Switched to factory rad and that issur went away. Willing to try putting the shroud and fan back on. But figured on track there should be more than enough airflow available the puller fan shouldnt be necessary?

If I didn't hit traffic the temps seemed to be stable, but as soon as I hit dirty air they spiked.

Yes, I was there for that event. I did all black sessions both days and one Red on Sunday. Temps were stable despite some Red traffic. I am all OE for cooling components.

[eacmen]

I just did 2 days at Summit Point with temps at 94-96 degrees both days. Oppressive. Zero problems on a stock, well-maintained setup. Instructor group, including two back-to-back sessions.

Were you at the NJ CCA event? I was there as well. My coolant temps were getting up to 220 and oil temps were getting up to 275.

I had to do cool down laps mid session.

I still have A/C with pusher fan. No puller fan. I used to have the CSF rad and just running A/C car would overheat at idle. Switched to factory rad and that issur went away. Willing to try putting the shroud and fan back on. But figured on track there should be more than enough airflow available the puller fan shouldnt be necessary?

If I didn't hit traffic the temps seemed to be stable, but as soon as I hit dirty air they spiked.

[eacmen]

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