Cooling Question

Hello cultured folk of the E9x breed

I have been running stock oil cooler and stock radiator for a very long time and have had no heating issues on track. I recently shortened my gears and now have some heating issues when running a full 20 minute session towards the final few laps.

My question is, since I am mildly poor and on a tight budget, would you rather upgrade the oil cooler or the radiator to do88? Both is out of the question for me at the moment. I may wait until I can prioritize funds for both but I question if maybe just upgrading one would help in the mean time. Thanks!

Narvin wrote

Hello cultured folk of the E9x breed

I have been running stock oil cooler and stock radiator for a very long time and have had no heating issues on track. I recently shortened my gears and now have some heating issues when running a full 20 minute session towards the final few laps.

My question is, since I am mildly poor and on a tight budget, would you rather upgrade the oil cooler or the radiator to do88? Both is out of the question for me at the moment. I may wait until I can prioritize funds for both but I question if maybe just upgrading one would help in the mean time. Thanks!

FCP sells DO88 now so that is a benefit to just buy it now.

get the Oil Cooler first, radiator probably isn't necessary tbh.

But it could also be a sign to replace your water pump and thermostat as well.

you can also try running Redline WW, after flushing your current coolant. should see the temps drop as well.

DCT or manual?

If DCT, then the DCT cooler is the priority and will make the biggest difference in temps.

I would do DCT then Oil, then Rad+PS in that order. (If I had to)

Oil cooler 100%. Even with a larger than DO88 oil cooler (Litchfield race cooler) I can only run 5-6 laps at Laguna before getting to 280-290f oil temp, and the water temp warning comes up. At thunderhill and BW though, I have no issues. I am planning to run a set of center racelouvers and see how much that helps.

EDIT: Also running the Epic oil diverter valve, 95% water/water wetter, 5% coolant, Motul 10w60, catless, still runs hot at Laguna.

Narvin I have a CSF radiator, DO88 oil cooler, and CSF power steering cooler that I’d sell you. They have a season on them but I’m taking the cooling in another direction. Send me a PM if interested!

These collectively worked great, my car is just in a full race conversion.

To clarify, I have dct! I already have the do88 trans cooler and a larger trans pan. No dct/trans fluid issues at all. I have already replaced my water pump and thermostat already.

@drlane I am interested in the oil cooler. Shoot me the price I’ll send you a PM.

Based off the comments, I think I’m going oil cooler next plus coolant flush. I currently just run OEM coolant and have not explored the other coolant options. I have been running liquimoly oil as well but maybe I need to explore other options now. My gearing is very short (3.85)

Narvin wrote

To clarify, I have dct! I already have the do88 trans cooler and a larger trans pan. No dct/trans fluid issues at all. I have already replaced my water pump and thermostat already.

@drlane I am interested in the oil cooler. Shoot me the price I’ll send you a PM.

Based off the comments, I think I’m going oil cooler next plus coolant flush. I currently just run OEM coolant and have not explored the other coolant options. I have been running liquimoly oil as well but maybe I need to explore other options now. My gearing is very short (3.85)

I would switch to redline water wetter coolant mix with DW I know when I did that on my previous car it definitely ran cooler.

danvitmon wrote

Oil cooler 100%. Even with a larger than DO88 oil cooler (Litchfield race cooler) I can only run 5-6 laps at Laguna before getting to 280-290f oil temp, and the water temp warning comes up. At thunderhill and BW though, I have no issues. I am planning to run a set of center racelouvers and see how much that helps.

EDIT: Also running the Epic oil diverter valve, 95% water/water wetter, 5% coolant, Motul 10w60, catless, still runs hot at Laguna.

I’m curious about this litchfield race cooler sounds pretty good, but the do88 is advertised at 69% larger core vs stock where the race is only 60% larger.

The most effective mod to address high temps at track is the oil diverter valve. It:s also the cheapest mod out there.

https://store.vacmotorsports.com/vac-motorsports-oil-diverter-valve-bmw-s65-p4057.aspx

This removes the oil cooler thermostat so oil will always flow thru the oil cooler. This will significantly increase the time it takes your oil to warm up from a cold start.

Redd wrote

The most effective mod to address high temps at track is the oil diverter valve. It:s also the cheapest mod out there.

https://store.vacmotorsports.com/vac-motorsports-oil-diverter-valve-bmw-s65-p4057.aspx

This removes the oil cooler thermostat so oil will always flow thru the oil cooler. This will significantly increase the time it takes your oil to warm up from a cold start.

Even with the stock cooler it’ll be effective? Or is it in conjunction with an upgraded cooler?

Redd wrote

The most effective mod to address high temps at track is the oil diverter valve. It:s also the cheapest mod out there.

https://store.vacmotorsports.com/vac-motorsports-oil-diverter-valve-bmw-s65-p4057.aspx

This removes the oil cooler thermostat so oil will always flow thru the oil cooler. This will significantly increase the time it takes your oil to warm up from a cold start.

After reading the thread (edit earlier), I have considered this option but still need to weigh the pros and cons as the car is still used as my daily driver

Narvin wrote

After reading the thread (edit earlier), I have considered this option but still need to weigh the pros and cons as the car is still used as my daily driver

I’m gonna be doing this along with an oil cooler I’ll let you know.

gh0stE92M3 wrote

Even with the stock cooler it’ll be effective? Or is it in conjunction with an upgraded cooler?

Works either ways

I did a write up on my oil diverter onservations a few years ago in my build thread. I showed AiM data comparing temps before and after its installation. It’s on page 50: https://www.m3post.com/forums/showthread.php?t=1158445&page=50 (scroll down the page a bit)

I followed up with a bit more info on page 79: https://www.m3post.com/forums/showthread.php?t=1158445&page=79 (need to scroll down in that page too)

Anyway, if you don’t feel like reading it, the conclusion is that the oil diverter does seem to help to some extent. Unfortunately, on this platform, there are no magical solutions to the engine overheating.

I did a write up on my oil diverter onservations a few years ago in my build thread. I showed AiM data comparing temps before and after its installation. It’s on page 50: https://www.m3post.com/forums/showthread.php?t=1158445&page=50 (scroll down the page a bit)

I followed up with a bit more info on page 79: https://www.m3post.com/forums/showthread.php?t=1158445&page=79 (need to scroll down in that page too)

Anyway, if you don’t feel like reading it, the conclusion is that the oil diverter does seem to help to some extent. Unfortunately, on this platform, there are no magical solutions to the engine overheating.

dogbone wrote

I did a write up on my oil diverter onservations a few years ago in my build thread. I showed AiM data comparing temps before and after its installation. It’s on page 50: https://www.m3post.com/forums/showthread.php?t=1158445&page=50 (scroll down the page a bit)

I followed up with a bit more info on page 79: https://www.m3post.com/forums/showthread.php?t=1158445&page=79 (need to scroll down in that page too)

Anyway, if you don’t feel like reading it, the conclusion is that the oil diverter does seem to help to some extent. Unfortunately, on this platform, there are no magical solutions to the engine overheating.

Great info! Definitely seems to be helpful. Lower consistent temps on hotter days. This convinced me to do it eventually. I unfortunately already did all the maintenance for the “while you’re in there” 2-3 years ago and am kind of lazy to do it again… luckily I have the fcp lifetime warranty so when I have some free time to do the diverter valve, I’ll do everything fresh all over again (ofh gasket, valve covers,water pump, thermostat, pulleys and tensioners, radiator hoses, spark plugs, fuel rail, actuators etc…)

Wishing I knew I was going to get this deep into tracking the car back when I did this lol

start with the basics- check the heat exchangers for rubber/bugs and the condition of your undertray. check coolant level.
i think one of the best value per dollar mods that actually helps with cooling are hood vents...

roastbeef wrote

start with the basics- check the heat exchangers for rubber/bugs and the condition of your undertray. check coolant level.
i think one of the best value per dollar mods that actually helps with cooling are hood vents...

Do you mean hood vents as in CF hood with vents?

roastbeef wrote

start with the basics- check the heat exchangers for rubber/bugs and the condition of your undertray. check coolant level.
i think one of the best value per dollar mods that actually helps with cooling are hood vents...

Did you see oil/coolant decrease when you installed hood vents? Or do you mean vents help to keep the engine bay cooler in general?

Redd wrote

Did you see oil/coolant decrease when you installed hood vents? Or do you mean vents help to keep the engine bay cooler in general?

i mean it's not gonna cool your oil thats for sure lol

but yeah it will reduce engine bay temps a bit more not by much.. but a bit more.. and help overall, there's really no con to hood vents other than cutting your hood if using trackspec or puretech.

zcp312 wrote

Do you mean hood vents as in CF hood with vents?

i have trackspec vents in my oem hood. for about $360 and a little bit of time, you can help make the cooling system more efficient.

Redd wrote

Did you see oil/coolant decrease when you installed hood vents? Or do you mean vents help to keep the engine bay cooler in general?

the vents help reduce underhood pressure. anytime you can reduce the pressure behind a heat exchanger, the more air is going to flow through it rather than around it and increase efficiency. same goes for a proper undertray. thats why i always mention the undertray on the subject of cooling. air will meet the oil cooler face and then mostly flow around it if the undertray isn't in place to force the air through the cooler.

i did see temperature improvements after installing vents. my car is pretty cold blooded... takes a long time to get up to temp on the street.

technically, the oil cooler doens't directly benefit from hood vents, as it is sealed off from the under hood area and vents out the under tray, but i believe the oil/water temps are somewhat sympathetic of each other.

I do have hood vents already. However, I currently am running no undertray

My stock oil cooler and radiator have 160K miles on it and are original.. they’re pretty much due for maintenance

Narvin wrote

I do have hood vents already. However, I currently am running no undertray

this is your answer. put the oem felt on.

i think we talked about this on ig? i forget.