N54 Cooling - Temp Control Logic and what are your temps during extended track use?

shushikiary

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Jun 4, 2018
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I like that what you suggested puts all 3 radiators in parallel, and that none of them overlap.

I think that testing that without an additional pump, and then with (with the second pump in true parallel and equally matched) is a very good idea to properly isolate if flow/pressure really are the problem or not, or if air flow is the problem. (aka I think you designed a good test setup).

I also like in your drawing that it seems only one radiator has 10 AN and the other two now get 38mm. If in your custom radiator you can increase the size to something larger like you suggested, like 14 AN, I would.

I know its a lot of work, but doing things the right way usually is, lol
 
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Asbjorn

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Mar 10, 2018
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I like that what you suggested puts all 3 radiators in parallel, and that none of them overlap.

I think that testing that without an additional pump, and then with (with the second pump in true parallel and equally matched) is a very good idea to properly isolate if flow/pressure really are the problem or not, or if air flow is the problem. (aka I think you designed a good test setup).

I also like in your drawing that it seems only one radiator has 10 AN and the other two now get 38mm. If in your custom radiator you can increase the size to something larger like you suggested, like 14 AN, I would.

I know its a lot of work, but doing things the right way usually is, lol

Alright, decision made. I will start sourcing parts, and should be back with test results in about a month or so. Here's to hoping that both iat and coolant temps will behave better than this old log back from when it all started. Setup was CSF only + VRSF 7.5 HD + two oil coolers. I miss those low iats, and maybe the non-stepped ER wont heat soak as much (surface area is the same between the two).

 
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Davidwarren

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Nov 6, 2016
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Yeah buddy! three full days of 85+ temps in the full sun, haulin ass. No issues. At IMS. Only real problem I had was I would start to get fuel starvation at under 1/4 tank in a fast, banked right hand sweeper.

That is my dad in the ZR1 that passes me. He got down to a 1:53, my quickest was this 1:56. I can live with being 3 seconds off a ZR1 on R7s.
 

Asbjorn

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Yeah buddy! three full days of 85+ temps in the full sun, haulin ass. No issues. At IMS. Only real problem I had was I would start to get fuel starvation at under 1/4 tank in a fast, banked right hand sweeper.

That is my dad in the ZR1 that passes me. He got down to a 1:53, my quickest was this 1:56. I can live with being 3 seconds off a ZR1 on R7s.

Nice driving. Trail braking and everything. Was missing sound though.
Why such a long way round turn 11?

I get fuel starvation as early as 33% at one certain track that has a 270deg right turn here in China. Even M4s get fuel starvation there if the fuel is low enough. As I have gotten faster and faster, the fuel level where starvation happens has gotten higher and higher.

Ended up replacing my lpfp as it felt like it was damaged. I had this feeling of vtec kicking in when passing 4000rpm. No lpfp sensor on the Z4 though, so no idea if it helped. Fortunately I was smart enough to go on track and quickly fuel starve the new pump as well... doh

Anyways three days at a track with no issues must be some kind of record for N54. Congratz! Does your diff still feel alright?
 

Davidwarren

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Nice driving. Trail braking and everything. Was missing sound though.
Why such a long way round turn 11?

I get fuel starvation as early as 33% at one certain track that has a 270deg right turn here in China. Even M4s get fuel starvation there if the fuel is low enough. As I have gotten faster and faster, the fuel level where starvation happens has gotten higher and higher.

Ended up replacing my lpfp as it felt like it was damaged. I had this feeling of vtec kicking in when passing 4000rpm. No lpfp sensor on the Z4 though, so no idea if it helped. Fortunately I was smart enough to go on track and quickly fuel starve the new pump as well... doh

Anyways three days at a track with no issues must be some kind of record for N54. Congratz! Does your diff still feel alright?
I'm running the public beta of ios13 on my phone, and the current version didn't record sound. :confused: I don't know why. Imagine a lot of wind and intake noise.
I passed that e46 heading into T11, and I gave him the inside of the turn. Despite how it looks on video, T11 is a nasty spot to lose it, and I wanted to give him plenty of space for safety and out of courtesy. I didn't want to cut him off by attacking the apex. Plenty of space anyway, not a huge loss of time.

I'm running the mFactory helical diff, so nothing really to wear out. Works great.

Knock on wood, but I've done 343 track laps in 2019 so far and my only issue was burning out my EKP. Which I replaced with the EOS unit and it has been flawless.
 

Asbjorn

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I'm running the public beta of ios13 on my phone, and the current version didn't record sound. :confused: I don't know why. Imagine a lot of wind and intake noise.
I passed that e46 heading into T11, and I gave him the inside of the turn. Despite how it looks on video, T11 is a nasty spot to lose it, and I wanted to give him plenty of space for safety and out of courtesy. I didn't want to cut him off by attacking the apex. Plenty of space anyway, not a huge loss of time.

I'm running the mFactory helical diff, so nothing really to wear out. Works great.

Knock on wood, but I've done 343 track laps in 2019 so far and my only issue was burning out my EKP. Which I replaced with the EOS unit and it has been flawless.

My quaife diff started having alot of slack after a one hour track session. They say it is because I used oem diff oil. Should have used thicker oil. They say it is particularly important for longer sessions where the diff oil might get hotter than usual.
 
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Davidwarren

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My quaife diff started having alot of slack after a one hour track session. They say it is because I used oem diff oil. Should have used thicker oil. They say it is particularly important for longer sessions where the diff oil might get hotter than usual.
I run Redline 75W140 and change it twice a year.
 
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Asbjorn

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The new coolers have finished production, and I am now ordering a bunch of 22mm ID silicone hoses in different shapes to get them installed. The manufacturer said they were able to use B-tubes for these.

Here's the 30mm one that will go behind the custom ER competition FMIC.

527458931.jpg


And below is the new driver's side aux radiator that was supposed to be a Derale copy as suggested by @shushikiary. I saw an opportunity to up-size a little by placing the 7/8in / 22mm outlets on the rear. It is also "only" 52mm/2in thick, because that was the thickest core available from my factory.

218169130.jpg


One idea that hit me was to install ball valves - one for both of these coolers. I foresee that this setup will still not be enough on +100F days, and being able to quickly compare the difference to stock on track would be nice. It could also be used to confirm if the radiator behind the FMIC is actually helping or not.

Another idea I originally got from @jts1981 was to use water spray outside the coolers. Now as I wouldn't want a wet car on track, low pressure water spray isn't an option. Low pressure water spray just makes the coolers wet, and cooling is achieved through evaporation. High pressure water mists are much better, as the air is cooled instantly and remains dry, but high pressure isn't really an option either. Therefore I decided to try medium pressure water spray. Same kind of atomization you use for water/meth injection. So in fact I just ordered two kits and will be using one to spray outside with a 60mL nozzle, using manual activation, and the other kit will spray post FMIC with a bigger nozzle, an be boost activated. All water only. Because M4 GTS.

121647714.jpg


BTW I would also like to see if I can convert the SSP transmission cooler to being thermostat controlled instead of manually activated. There's an unused fitting on the SSP oil pan that could be used to install a temperature sensor, although the pressure is fairly high. The BMW ST813 document, describing how the M DCT Drivelogic works, says that the M oil cooler thermostat opens at 95C / 203F so this is what I would be targeting for tuning on/off the DCT oil pump.

And speaking of oil cooling. Since I am going to pull the differential anyway, to try and fix the slack from using wrong oil at the track, I am thinking why not use the fittings and leftover oil coolers to make a thermostat controlled differential oil cooler like this:

1415438713.jpg


My only question is, what should the set point be for a differential oil thermostat. What is normal operating temperature for a Quaife / helical differential? 95C like the DCT?
 
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shushikiary

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Are those radiators not cross flow? For the height (number of horizontal rows) of the first radiator you posted cross flow might not be that big of a deal, but for the second radiator you posted it might be. Coolant can end up being trapped at the end of the radiator if not cross flow and a large height of radiator.... of course they might be double pass or something and I just can't tell from the photo's, which would make my comment moot.
 

Asbjorn

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Are those radiators not cross flow? For the height (number of horizontal rows) of the first radiator you posted cross flow might not be that big of a deal, but for the second radiator you posted it might be. Coolant can end up being trapped at the end of the radiator if not cross flow and a large height of radiator.... of course they might be double pass or something and I just can't tell from the photo's, which would make my comment moot.

F :tearsofjoy:

My experience with cross flow is that it takes forever to get air out. Anyhow, both are single flow because I ordered them like that.....

EDIT this M4 aux cooler is actually taller than mine, although mounted horizontally instead of vertically.

IMG_20190703_170343.jpg
 
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shushikiary

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Well one easy way to tell if its even a problem or not is to just use one of those laser thermometers after its stupid hot and measure the side of the radiator with the outlets vs the side without. If there's a large temperature difference then you know its not working as well as it could because its not cross flow or dual pass. If there isn't a differential then its likely working fine.
 

gmx

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Dec 8, 2017
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Running much less thermal output than you but my dual oil cooler shrouded setup is continuing to do fine. Peak oil temps 116C. Last two outings were on
1) high speed circuit:

2) low speed circuit that's hard on tyres/brakes - forgot my camera. The only high speed sections are two small straights/kinks into 4th gear briefly. I'm seeing a drop-off on this set of tyres and couldn't take the kink flat - few tank slappers were had around 100mph :D Didn't punch above 114C on oil.

Water doesn't go above 98C. Ambient on both was around 17-25C mark. I can actually enjoy and drive the s&^t out of the car. Only tyres hold me back. Proper set of semis (pref A050 mediums) next after WTAC here in Sydney. I have 3 sets of 1M wheel liners. Still on shrouded OEM. One of them is cut up, I made custom louvres for with more area for heat extraction. There's a bit room if I need it while keeping it fairly OEM.
 
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Asbjorn

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Running much less thermal output than you but my dual oil cooler shrouded setup is continuing to do fine. Peak oil temps 116C. Last two outings were on
1) high speed circuit:

2) low speed circuit that's hard on tyres/brakes - forgot my camera. The only high speed sections are two small straights/kinks into 4th gear briefly. I'm seeing a drop-off on this set of tyres and couldn't take the kink flat - few tank slappers were had around 100mph :D Didn't punch above 114C on oil.

Water doesn't go above 98C. Ambient on both was around 17-25C mark. I can actually enjoy and drive the s&^t out of the car. Only tyres hold me back. Proper set of semis (pref A050 mediums) next after WTAC here in Sydney. I have 3 sets of 1M wheel liners. Still on shrouded OEM. One of them is cut up, I made custom louvres for with more area for heat extraction. There's a bit room if I need it while keeping it fairly OEM.

Tank slappers at 100mph??? holy effing moly! That's one of my biggest fears come true right there. Sounds like it is time to hit the skid pad and practice some 3rd gear drift exits?

Anyhow, 116C peak oil and 98C peak water actually sounds like you would be better off replacing the second oil cooler with an aux radiator. I mean I would be happy to give up a bit of oil temps for lower water temps. What are you thinking?
 

gmx

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Dec 8, 2017
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Well that happened to be the secret sauce. I think it was mentioned in this very thread that the aux radiator on the 1M/N54 isn't very well thought out from factory, it's not easy to put them in series and this is why the tubing that diverts coolant to it is so small (beyond my memory). As a result, we still get poor cooling.

I switched from the OEM setup, aux oil cooler and aux radiator to dual oil coolers straight away rather than single then dual. I also do not run a thermostat anymore. To aid warmup I tape the front inlets. Little price to pay. Logistically it's difficult to fit the an external / remote thermostat. I bought the Improve Racing one, ended up not using it after a quick look.

The only way I'd use it is if it lines up with common blockoff plate holes (these are important,they're not randomly placed) and weld 90deg SS bungs. Then screw it in from beneath. At this point, may as well just buy something like MSL's billet thermostat. Only negative of that one, imo, is -8AN male fittings.
 

Asbjorn

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Mar 10, 2018
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European, based in China
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Well that happened to be the secret sauce. I think it was mentioned in this very thread that the aux radiator on the 1M/N54 isn't very well thought out from factory, it's not easy to put them in series and this is why the tubing that diverts coolant to it is so small (beyond my memory). As a result, we still get poor cooling.

I switched from the OEM setup, aux oil cooler and aux radiator to dual oil coolers straight away rather than single then dual. I also do not run a thermostat anymore. To aid warmup I tape the front inlets. Little price to pay. Logistically it's difficult to fit the an external / remote thermostat. I bought the Improve Racing one, ended up not using it after a quick look.

The only way I'd use it is if it lines up with common blockoff plate holes (these are important,they're not randomly placed) and weld 90deg SS bungs. Then screw it in from beneath. At this point, may as well just buy something like MSL's billet thermostat. Only negative of that one, imo, is -8AN male fittings.

Well I've been running dual oil coolers for more than a year as my car didn't come with an aux radiator. It was only recently that I decided to add the side aux radiators, there by hindering some of the airflow to those oil coolers.

I just made this quick video walkthrough of my now old setup using a gopro video I took today and the screen recorder on my phone.