Tracking car hard in hot climate

[Nardo S54]

I’m on east coast but have my share of hot weather track days. Just last week my ambient temps read 105 in my Z4. But I typically do (6) 30-min sessions per day at my local track. Temps are usually 220-230 if I shift before 7500. If I take it to redline, then temps climb to mid 240s.

I did a full cooling refresh and stuck with OEM/OE parts. While I considered CSF rad, truth is the factory rad with plastic end tanks never once leaked in the last 18 years, and temp management has never been issue. So just did BMW genuine which was surprisingly reasonably priced from FCP.

The only piece I didn’t touch was the oil cooler and that was only because the item is currently NLA for the Z4 M. I was considering going with an aftermarket from Zionsville but wasn’t able to verify fitment since the Z4 application isn’t very common (and I hate being the guinea pig).

[elbert]

I was considering a do88 oil cooler, but now I'm not so sure after seeing this thread. Granted, it is for a different car, but QC is QC.

https://www.m3post.com/forums/showthread.php?t=2156902

[Obioban]

There is no way a OEM rad/oil cooler would ever keep up with the D088 if you are at all an advanced/top level driver. Even if new.

Since you never actually tried a new OE rad in your journey, I'm not sure what you're basing that on.

Oil cooler I'll give you. Stock cooler seems to always lock on at ~3/4 and hold. If the D088 is keeping it below the half way mark, that's certainly an improvement.

[bigjae46]

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.

Where are you shifting? That makes a huge difference. I can run all day shifting at 7k rpm. I get about 15-20 minutes in 90+ degree weather shifting at redline.

[Estoril]

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.

[Driver407]

Been a while since I checked in on this thread. (Three years or so) In that time I have completely revamped my entire cooling system. Figured I would leave some information.

Last few years I have been hitting the limit of the cooling on days above 85~ or so. Coolant was usually the first thing to blast off.
About a year ago I upgraded the OEM radiator with a DO88 radiator. Ran a few 95-100 degree days last year. Allowed me to stay out longer and definitely was an improvement over the stock unit.
It did leave me wanting more though... I had to do a cooldown lap and still had to monitor temps. The coolant was just a little peaky at times. Wasnt going into the red-red zone though.

Two months ago. I decided to fully revamp the cooling system from the ground up to resolve any unknown maintenance history.
Which included DO88 oil cooler, new thermostat, new sensors, waterpump, coolant, water wetter. In addition to gorilla taping any seams to channel air into the radiators. (Still on clutch fan fwiw)

Was out at Thunderhill 5-mile last weekend (91 high) and my coolant peaked at 208 and oil never hit the middle dot. Didnt even do cooldown laps to fully pressure test.
The entire block is cooler since the oil doesnt peak as high. Which cascades to slightly lower coolant temps. It wasnt much lower but it was enough to level out the peaky coolant temps without it.
Not the hottest day but a good initial test of everything on a warmer day. Ive also tried to not track in extreme weather the last couple years regardless if the car can handle it.

Quite a few of us track rats in the NorCal area that run the entire DO88 cooling setups on our E46's. (Many of us are the fastest drivers in the area) Part of why I went down this path - from all the positive feedback.
Not sure why people are recommending OEM for a track build in the initial postings of this thread. Done nearly 40 track days since that original post and know the car intimately now. I'm in the top percentile of lap times at all the local tracks in my E46. There is no way a OEM rad/oil cooler would ever keep up with the D088 if you are at all an advanced/top level driver. Even if new.

Figured id share my experience over the years and what I would recommend to anyone looking to build out a proper track car.

Heres a lap from last weekend while im here:

[Tonggi]

I have a DO88 Oil cooler and radiator, 70C thermostat. Tracked at Sebring in 80 ish F temps with high humidity and I never got worried about temps, stock fan clutch and mechanical fan. 100% water (bcuz FL) the 70C helps keep car cooler at the start but once it gets to temps its useless and helps get the car even cooler afterwards since its cooling below 80.

All the E92 guys rave about DO88 so I jumped on it and I've been happy since. I think OEM was fine as well, probably would be awesome with the 70C as long as its cleaned up (the fins) from debris.

[Obioban]

100% correct. With both stock fans, and that factory ducting, you can happily blast the AC in any ambient conditions with no coolant temp rise.

[Hotchkess]

I've been running a Bimmerworld/C&R radiator with no issues on track but will get the needle rising around town with A/C on at low speed (Austin, TX 100+ F). Do most people replace A/C condenser at higher miles as well? I'm at 215k miles on chassis, about 57k miles on this aluminum radiator. At this point I don't like to drive the car around town if its 90+ F outside. Not sure if others are able to blast A/C around town in hot climates but would like to address this if possible. Have OE oil cooler (few years old) and a Mishimoto electric fan

I’d be willing to take a bet and say your issue is the Mishimoto fan you’re running. From my understanding, the only way you’re going to have solid coolant temps while street driving and running AC in hot environments like here in Austin is if you either stick with the stock fan setup (OEM aux fan and clutch fan), or run the Mishimoto fan in tandem with the aux fan, therefore having a two fan setup. I’m running into a similar issue with my single Spal fan I’m running right now, and plan on switching back to the stock aux + clutch fan setup in the near future.

[elrichmeister]

I've been running a Bimmerworld/C&R radiator with no issues on track but will get the needle rising around town with A/C on at low speed (Austin, TX 100+ F). Do most people replace A/C condenser at higher miles as well? I'm at 215k miles on chassis, about 57k miles on this aluminum radiator. At this point I don't like to drive the car around town if its 90+ F outside. Not sure if others are able to blast A/C around town in hot climates but would like to address this if possible. Have OE oil cooler (few years old) and a Mishimoto electric fan

Not sure if you still have mechanical fan, but replacing fan clutch fixed my High Ambient 95F+ AC high coolant temps.

[S54330Ci]

I swapped my OE radiator and oil cooler for CSF units. I also installed a BMW Motorsports thermostat.

https://www.bimmerworld.com/Motorsport-Thermostat-E46-M3-E36-Euro-M3.html

My oil temps on 90 degree (35% humidity) track days never go above 250 degrees and water temps stay around 178 to 188 degrees (per my ScanGuage). Typically run 20 minute sessions.

[bigjae46]

Wild to me that every person that's been with this platform and gone there and back with it all say don't go away from OEM radiator and still ppl do... Now we're also at the point where OEM radiators are not from Modine anymore which is sad, not sure if anyone has metered use with the new Modine "owner company" (name transfer or whatever.

In terms of oil temps, new OEM oil cooler and surrounding hardware new OEM is known to have drastic improvements on lowering temps. You have a 24 year old platform with 24 years of use that many times was not you at the wheel or underneath it to care for it. I see oil coolers as the only real improvement over OEM and id never give my money to CSF. d088 is where id go for a like OEM replacement with increased capacity and a lower weight penalty.

I have a CSF and I got lucky...it works as well as I need it to. My water temps used to be about 175 even on hot days before my oil cooler line o-ring exploded. My radiator now has a bunch of dirt and grime stuck to it so the car runs about 185ish now.

I think a lot of people compare a beat to shit OEM radiator to a new aftermarket radiator and conclude that aftermarket is better which makes no sense to me.

I will say that the car needs better oil cooling assuming the car is stock. Even a brand new OE oil cooler isn't enough. I think ducting the cooler out of the undertray would make the OE oil cooler borderline adequate.

I've been thinking about using a full face oil cooler on the back of the radiator. I need to find a 1" thick oil cooler, attach it to the radiator and close off any gaps so all of the air goes through the oil cooler. There are some other complications that I also need to work through.

[elbert]

Did you delete the pusher fan?
.

This.

[bigjae46]

I've been running a Bimmerworld/C&R radiator with no issues on track but will get the needle rising around town with A/C on at low speed (Austin, TX 100+ F). Do most people replace A/C condenser at higher miles as well? I'm at 215k miles on chassis, about 57k miles on this aluminum radiator. At this point I don't like to drive the car around town if its 90+ F outside. Not sure if others are able to blast A/C around town in hot climates but would like to address this if possible. Have OE oil cooler (few years old) and a Mishimoto electric fan

Did you delete the pusher fan?

The condenser is what takes all of the beating - bugs, sand, debris, etc. I'd think that replacing it would help.

[dreamdrivedrift]

dreamdrivedrift Have you tried it in warmer weather?

Did a drift day and it performed, hoping to get it on track again in the next couple months