[Polo08816]

Originally Posted by visionaut

If you’d like to really lower your temps, in a way you can notice daily, I can’t recommend the Mosselman oil thermostat for the outboard oil cooler enough. I’m super happy to never see 250F anymore. ‘Yeah yeah, hotter is more efficient blah blah blah’ - but performance is always better at 220F.

Originally Posted by Boostedphil698

I 100% will be doing that thermostat.

I have the Mosselman oil thermostat as well coupled with the CSF N55 race oil cooler.

As far as cooling mods, I've replaced the coolant radiator with a CSF radiator.

When you get a chance, take a look at your auxiliary coolant radiator on the driver's side bottom. If all your fins are all bent from years of use, consider replacing that as well via FCP Euro.

[AmuroRay]

Originally Posted by AmuroRay

temps increased with CSF radiator:
https://f87.bimmerpost.com/forums/sh....php?t=1525790

Marginal decrease (3f) in oil temps
https://www.2addicts.com/forums/show....php?t=1864339

Literally car got hotter with the CSF cooler:
https://f87.bimmerpost.com/forums/sh....php?t=2024707

Originally Posted by SuperMarioM2

Love this thread. I also track my 2017 N55 M2 regularly and so I have some of the same issues. The funny thing is, I've taken a very similar path over the years and never saw this thread until now.

Difference is my M2 is a 6 spd manual, and my oil temps have always been lower. Likely because the DCT? By lower, I mean on track in Florida, at Sebring and Homestead in June and even July I usually don't see oil temps above 255 or 260 max. IAT's are high (up to 150 and more).

Also started out with a Dinan Stage 4 setup, then changed to Bootmod3 Stage 2. I also removed most of the Dinan mods except the turbo and went FBO using FTP pipes and the Wagner Evo 2 Comp. - it's so much lighter than the Dinan and doesn't require cutting the car into pieces...

I tried the CSF radiator (the non AC delete version) and my coolant temps went up. That's the ONLY time my M2 ever overheated on track. Temps were also higher on the street, but no overheating issues there. The fix was to remove the CSF radiator and run the stock version. Weird, but that was my experience...

I also added the GTS aluminum hood from Suvneer and have to say the fit and finish is very good. I can't say whether it actually reduces temps, but would guess not in any significant way.

I'm also running the CSF oil cooler, the Turbosmart BOV and an upgraded XDI-35 HPFP and Spool Stage 2 LPFP. I've also started running an e30 flex fuel BM3 map recently and love the power it makes. Setting up 3 custom maps now using the Bend Calibration Ultimate BM3 Flex Fuel kit read the ethanol content of the fuel and pass the info to the car via their wiring harness that plugs into the CAN Bus. It's a really cool setup where the car reads the "e" content live and BM3 adjusts the maps accordingly. I haven't had it on track yet with this setup, but should be able to report back after HMS track day coming up on Nov. 7th.

Would love to see more data on that Evo3 on track. I've seen the same data as shared here and it looks impressive. What was the install like? Any cutting needed?

^

Originally Posted by ZM2

Nice! Sounds very similar to my path!

I have to admit the CSF radiator has always been suspect for me, but I had not heard of anyone changing from it back to OEM, and coolant (and oil) temps then went down.

Can you confirm that with any data or more details about your track outings that confirmed the CSF radiator was the issue?

Thanks!

Originally Posted by -Eidos

If you decide to run a DCT trans cooler, then take this as you will:

I run a CSF radiator and the fitment is garbage - this was before I found out that do88 carries cooling parts for the F87.

Definitely go for the do88 since the pricing is similar:
https://www.do88.se/en/artiklar/bmw-...er-racing.html

https://f87.bimmerpost.com/forums/sh....php?t=1825098

[AmuroRay]

Originally Posted by Polo08816

Those are products that are not applicable to our chassis.

The "CSF radiator" is an intercooler. I've never had experience with that since my intercooler is the Wagner Tuning Evo 2 Competition.

The 2addicts thread oil cooler setup is nothing that I've ever seen before the F30 chassis.

The F87 thread is again, about an intercooler and not a coolant radiator.

My guy - I have a 2 series, and the their radiator for the M2/M235i is NOT an intercooler. And yeah, CSF lists the same P/N for the F87 and the F22/30:

https://www.torqued.io/csf-12-16-bmw...minum-radiator

The 2 addicts thread is a guy using a dual oil cooler setup after the CSF cooler reduced the temps by 3F.

Originally Posted by Polo08816

So the design of the oil coolers on the M cars is distinctly different than the non M cars. The M2 and CSF oil coolers are a single pass design - note that the CSF cooler (like the M2 oil cooler) require an additional half a quart of engine oil. They flow oil through in a way that is far more effective at lowering temps.

The M2's oil cooler is taller (more rows) but otherwise the same - and yet despite CSF's changes, it's cooler was only able to reduce temps by 3F over the factor oil cooler.

[Polo08816]

Originally Posted by AmuroRay

My guy - I have a 2 series, and the their radiator for the M2/M235i is NOT an intercooler. And yeah, CSF lists the same P/N for the F87 and the F22/30:

https://www.torqued.io/csf-12-16-bmw...minum-radiator

The 2 addicts thread is a guy using a dual oil cooler setup after the CSF cooler reduced the temps by 3F.




The M2's oil cooler is taller (more rows) but otherwise the same - and yet despite CSF's changes, it's cooler was only able to reduce temps by 3F over the factor oil cooler.

I took a quick look at some of those posts, but it's also in a thread with 15 pages.

It's a moving goal post because those people have heavily modified powertrains.

If I had an M car with a relatively stock powertrain, I would not be changing out parts for aftermarket cooling parts unless there was a convincing reason to do so. From what I've seen at HPDEs, stock powertrain M cars have almost no issues with engine cooling - from just eyeballing the dash temperature gauge they run ice cold. Their biggest issues are not enough front axle negative camber and the need for track pads.

3F is insignificant. It's questionable whether a temperature sensor is precise enough for that to be significant. Also, keep in mind, that temperature sensor takes an instantaneous reading at one place in the entire system at a point in time (ie. https://www.realoem.com/bmw/enUS/sho...51#13621433076).

The only way to know for sure is to be able to know how restrictive a heat exchanger is to flow as well as the temperature drop between the inlet and outlet. That's the empirical data that we would need to know to definitively say that a heat exchanger is effective or useless. I don't think anyone of us are able to create a controlled environment to conclusively say one way or another.

[AmuroRay]

Originally Posted by Polo08816

I took a quick look at some of those posts, but it's also in a thread with 15 pages.

It's a moving goal post because those people have heavily modified powertrains.

If I had an M car with a relatively stock powertrain, I would not be changing out parts for aftermarket cooling parts unless there was a convincing reason to do so. From what I've seen at HPDEs, stock powertrain M cars have almost no issues with engine cooling - from just eyeballing the dash temperature gauge they run ice cold. Their biggest issues are not enough front axle negative camber and the need for track pads.

If by modified, you mean bolt ons and tune - sure, that's the majority of this forum. I think one guy had (at the time of one of the posts) a Dinan turbo.

But M2's do seem to have more cooling issues than others at the track.

Originally Posted by Polo08816

3F is insignificant. It's questionable whether a temperature sensor is precise enough for that to be significant. Also, keep in mind, that temperature sensor takes an instantaneous reading at one place in the entire system at a point in time (ie. https://www.realoem.com/bmw/enUS/sho...51#13621433076).

The only way to know for sure is to be able to know how restrictive a heat exchanger is to flow as well as the temperature drop between the inlet and outlet. That's the empirical data that we would need to know to definitively say that a heat exchanger is effective or useless. I don't think anyone of us are able to create a controlled environment to conclusively say one way or another.

You can read real time temps in BM3 and MHD, I do it all the time. The 3F is meaningless because the CSF stuff really doesn't work that well.

[Polo08816]

Originally Posted by AmuroRay

If by modified, you mean bolt ons and tune - sure, that's the majority of this forum. I think one guy had (at the time of one of the posts) a Dinan turbo.

But M2's do seem to have more cooling issues than others at the track.



You can read real time temps in BM3 and MHD, I do it all the time. The 3F is meaningless because the CSF stuff really doesn't work that well.

I don't think bolt-ons significantly change the parameters of a powertrain. It's the tune that is questionable for track applications.

I know you can read real time temps in BM3. I also do it in RaceChrono at the track which I would argue is a better way of capturing data for a track scenario. That doesn't change the fact that the temperature reading you are getting is based on 1 sensor at one specific place in the cooling system as a whole system. It's not providing you data such as flow rate through an exchanger and the temperature delta between the inlet and outlet which is what you really need to determine whether the exchange is effective.

Also, the 3F variance is meaningless because what it tells us is that the stock cooling system as well as the modified cooling system's heat capacity and ability to shed heat isn't being challenged to the point where you can tell the difference. The 3F variance is more likely to be related to when the coolant thermostat is opening.

However, what I can tell you is that after the Mosselman thermostat and CSF engine oil cooler, my front passenger TPMS always reads 5-10F higher than the other 3 tires. And I have square wheel/tire setups so I can rotate it every 2,500 miles or 5,000 miles to coincide with my oil changes [every 2,500 miles during track season].

A 5-10F increase in TPMS temperatures after the install of the Mosselman thermostat and CSF engine oil means that it's shedding a decent amount of heat during regular highway speed driving.

[AmuroRay]

Originally Posted by Polo08816

I don't think bolt-ons significantly change the parameters of a powertrain. It's the tune that is questionable for track applications.

I know you can read real time temps in BM3. I also do it in RaceChrono at the track which I would argue is a better way of capturing data for a track scenario. That doesn't change the fact that the temperature reading you are getting is based on 1 sensor at one specific place in the cooling system as a whole system. It's not providing you data such as flow rate through an exchanger and the temperature delta between the inlet and outlet which is what you really need to determine whether the exchange is effective.

So flow rate is more important than actual temperature deltas and maximum temps (which trigger limp modes)
Agree to disagree.

Originally Posted by Polo08816

Also, the 3F variance is meaningless because what it tells us is that the stock cooling system as well as the modified cooling system's heat capacity and ability to shed heat isn't being challenged to the point where you can tell the difference. The 3F variance is more likely to be related to when the coolant thermostat is opening.

That's actually not what was said. To paraphrase, the MAXIMUM temperatures achieved were only 3F lower than the stock oil cooler. People aren't buying oil coolers for "flow", they are buying them to keep the oil from breaking down at higher temperatures.

Originally Posted by Polo08816

However, what I can tell you is that after the Mosselman thermostat and CSF engine oil cooler, my front passenger TPMS always reads 5-10F higher than the other 3 tires. And I have square wheel/tire setups so I can rotate it every 2,500 miles or 5,000 miles to coincide with my oil changes [every 2,500 miles during track season].

A 5-10F increase in TPMS temperatures after the install of the Mosselman thermostat and CSF engine oil means that it's shedding a decent amount of heat during regular highway speed driving.

?????

I'm not sure how that works - maybe you should check your alignment.

[Polo08816]

Originally Posted by AmuroRay

So flow rate is more important than actual temperature deltas and maximum temps (which trigger limp modes)
Agree to disagree.



That's actually not what was said. To paraphrase, the MAXIMUM temperatures achieved were only 3F lower than the stock oil cooler. People aren't buying oil coolers for "flow", they are buying them to keep the oil from breaking down at higher temperatures.


?????

I'm not sure how that works - maybe you should check your alignment.

Re: 3F, it seems like the issue is their factory oil thermostat is opening up at a pre-set temperature to allow flow to the oil cooler. Once the oil cooled off enough, that thermostat would close back up. Sounds like normal operation for a cooling system that is operating within its capacity - with both the stock and modified cooler. In fact, if you think about it, if the CSF cooler brought the temperature down 3F more than the stock cooler, that means in that the miniscule delay that it takes the stock oil thermostat to close up, the modified cooler brought it down an extra 3F. That's actually significant in my opinion. If the oil thermostat was open for an very extended period of time and the temperature difference was only 3F, I'd say the CSF cooler would be completely worthless.

As far as the temperature readings off the TPMS, it's not an alignment issue because I know for a fact the specs are the same between the left and right sides. Tire wear is even. The car is gets alignments 2-4 times a year at the dealer because I like to experiment with alignment specs. If you were generating that type of temperature delta from an alignment issue, I would be able to detect from a quick check with my toe plates as well.

Honestly, it sounds like most people on those other forums don't really understand how their cooling system works. They've become incredibly complicated these days because not everything is plumbed in series. Once you start plumbing in parallel, it becomes monumentally harder to understand the consequences or effects of a modification in just part of that circuit. You'd really need an engineer in fluid dynamics. Even your technician working in a dealership shop won't be able to explain the parameters of that system with the specificity needed to actually understand the system when it's pushed to its mechanical limit.

[AmuroRay]

Originally Posted by Polo08816

Re: 3F, it seems like the issue is their factory oil thermostat is opening up at a pre-set temperature to allow flow to the oil cooler. Once the oil cooled off enough, that thermostat would close back up. Sounds like normal operation for a cooling system that is operating within its capacity - with both the stock and modified cooler. In fact, if you think about it, if the CSF cooler brought the temperature down 3F more than the stock cooler, that means in that the miniscule delay that it takes the stock oil thermostat to close up, the modified cooler brought it down an extra 3F. That's actually significant in my opinion.

It's already open at this point - the temperatures were 267F to 264F, this is well above the stock thermostat being open and into the limp mode territory.

Originally Posted by Polo08816

As far as the temperature readings off the TPMS, it's not an alignment issue because I know for a fact the specs are the same between the left and right sides. Tire wear is even. The car is gets alignments 2-4 times a year at the dealer because I like to experiment with alignment specs. If you were generating that type of temperature delta from an alignment issue, I would be able to detect from a quick check with my toe plates as well.

Could be added weight, it could be heat, it could be alignment - I would check.

[Polo08816]

Originally Posted by Polo08816

Re: 3F, it seems like the issue is their factory oil thermostat is opening up at a pre-set temperature to allow flow to the oil cooler. Once the oil cooled off enough, that thermostat would close back up. Sounds like normal operation for a cooling system that is operating within its capacity - with both the stock and modified cooler. In fact, if you think about it, if the CSF cooler brought the temperature down 3F more than the stock cooler, that means in that the miniscule delay that it takes the stock oil thermostat to close up, the modified cooler brought it down an extra 3F. That's actually significant in my opinion. If the oil thermostat was open for an very extended period of time and the temperature difference was only 3F, I'd say the CSF cooler would be completely worthless.

As far as the temperature readings off the TPMS, it's not an alignment issue because I know for a fact the specs are the same between the left and right sides. Tire wear is even. The car is gets alignments 2-4 times a year at the dealer because I like to experiment with alignment specs. If you were generating that type of temperature delta from an alignment issue, I would be able to detect from a quick check with my toe plates as well.

Honestly, it sounds like most people on those other forums don't really understand how their cooling system works. They've become incredibly complicated these days because not everything is plumbed in series. Once you start plumbing in parallel, it becomes monumentally harder to understand the consequences or effects of a modification in just part of that circuit. You'd really need an engineer in fluid dynamics. Even your technician working in a dealership shop won't be able to explain the parameters of that system with the specificity needed to actually understand the system when it's pushed to its mechanical limit.

Originally Posted by AmuroRay

It's already open at this point - the temperatures were 267F to 264F, this is well above the stock thermostat being open and into the limp mode territory.



Could be added weight, it could be heat, it could be alignment - I would check.

Is your theory that once the engine reaches 250F (approximate), the stock oil thermostat remains open and never closes? I'm not sure I agree with that.

I think it opens and closes repeatedly during regular operation because the factory oil cooler design is more than sufficient for normal use and even HPDE use. (I only upgraded the cooling system because the car was being shared which would result in the car being run back to back in different sessions for 50+ minutes continuous.)

Keep in mind, there are N55 cars (like my X3 35i) that do not have an oil thermostat and engine oil cooler behind the front fascia. I would submit to you that the N55 platform, in normal driving, doesn't even really require the engine oil cooler. A liquid to liquid heat exchanger with the coolant system is sufficient to keep temperatures within operating range.

The point that I'm making is that with the stock oil thermostat, a 3F difference is insignificant and if you're saying the temperatures still go to 264F-267F, then the stock oil thermostat is the limiting factor. It's very well the case that in normal use with the stock oil thermostat, someone wouldn't be able to benefit/realize the difference between a factory oil cooler and a modified oil cooler. If the thermostat decides to not flow oil, there's nothing that the factory or aftermarket cooler can do.


Also, the temperature effect on the front passenger tire is not due to added weight or alignment. It's been like that for 30,000+ miles out of my car's 155,000 mile life. It's also been like that through 2 different suspension setups (M Performance Suspension kit and Ohlins R&T) as well as another M3 control arm replacement where I've had the Mosselman oil thermostat and CSF oil cooler. If it were a weight issue or an alignment issue, trust me, I would have noticed in regular driving or at the track. I also know that it's not a braking issue because when I come off track, I inspect the rotor temperatures with an laser temp gun and the left and right sides are pretty much the same. I also rebuild my calipers from time to time. With that type of temperature differential in the tires, if you're not feeling the change in balance or handling, you're have to be in the novice group.

[rlesko]

Polo08816 do you have the auxiliary transmission radiator on your car?

[Polo08816]

Originally Posted by rlesko

Polo08816 do you have the auxiliary transmission radiator on your car?

Yes, because it is an M Sport and Sport Automatic Transmission vehicle. There is a transmission radiator (that flows regular coolant to the liquid to liquid transmission heat exchanger) that sits in front of the coolant radiator. However, I question if it's an "auxiliary" transmission radiator because I don't think there is a "primary" transmission radiator.

[rlesko]

Originally Posted by Polo08816

Yes, because it is an M Sport and Sport Automatic Transmission vehicle. There is a transmission radiator (that flows regular coolant to the liquid to liquid transmission heat exchanger) that sits in front of the coolant radiator. However, I question if it's an "auxiliary" transmission radiator because I don't think there is a "primary" transmission radiator.

Yea, thats a fair point about how to refer to it.

I was curious how that transmission cooler is connected to the cooling circuit - it sounds like you're telling me its connected to the heat exchanger that hangs on the radiator fan cowl? (I do see two different part numbers for that heat exchanger- 17217600550 & 17217600553 )

Although based on the research that has been done so far it seems like the rest of the cooling circuit could be converted to 'M Sport' and this could be left as-is.

[zinner]

Originally Posted by Polo08816

I took a quick look at some of those posts, but it's also in a thread with 15 pages.

It's a moving goal post because those people have heavily modified powertrains.

If I had an M car with a relatively stock powertrain, I would not be changing out parts for aftermarket cooling parts unless there was a convincing reason to do so. From what I've seen at HPDEs, stock powertrain M cars have almost no issues with engine cooling - from just eyeballing the dash temperature gauge they run ice cold. Their biggest issues are not enough front axle negative camber and the need for track pads.

3F is insignificant. It's questionable whether a temperature sensor is precise enough for that to be significant. Also, keep in mind, that temperature sensor takes an instantaneous reading at one place in the entire system at a point in time (ie. https://www.realoem.com/bmw/enUS/sho...51#13621433076).

The only way to know for sure is to be able to know how restrictive a heat exchanger is to flow as well as the temperature drop between the inlet and outlet. That's the empirical data that we would need to know to definitively say that a heat exchanger is effective or useless. I don't think anyone of us are able to create a controlled environment to conclusively say one way or another.

I will just add my XP, I have a 2015 335i Manual Gear box with a Pure Stage 2/ XDI fuel pump and BM3 2H tune. Stock cooling system never hit a limp mode and I am running with the A group.

[Polo08816]

Originally Posted by rlesko

Yea, thats a fair point about how to refer to it.

I was curious how that transmission cooler is connected to the cooling circuit - it sounds like you're telling me its connected to the heat exchanger that hangs on the radiator fan cowl? (I do see two different part numbers for that heat exchanger- 17217600550 & 17217600553 )

Although based on the research that has been done so far it seems like the rest of the cooling circuit could be converted to 'M Sport' and this could be left as-is.

So for M Sport cars with the ZF 8HP, it'll be part number 17217600553:
https://www.realoem.com/bmw/enUS/sho...diagId=17_0638

I recall it being plumbed somehow with #13 here: https://www.realoem.com/bmw/enUS/sho...diagId=17_0674

I don't want to provide the wrong information because I don't remember exactly how.

However, if you remove the intercooler (to be able to look up into that space ) and remove the engine coolant expansion tank, it will all be clear and make sense or at least be as clear as mud.

One thing I will say is that the 3 coolant hose connections going into the top passenger side vicinity of the radiator can be confusing. If you are going to disconnect those, I recommend labeling which inlet/outlet they wil go into. I believe the lower 2 of those will go to the air to liquid transmission coolant radiator. The way the connector of those hoses "bend" doesn't make it 100% clear which hose goes where - if I remember correctly, they all appeared to have similar diameter connectors. Perhaps I got lucky and got it on the first try so the resulting coolant flow wasn't wrong. Otherwise, maybe they should have filmed my engine as the core of the nuclear powerplant in the HBO series Chernobyl.

[AmuroRay]

Originally Posted by Polo08816

Is your theory that once the engine reaches 250F (approximate), the stock oil thermostat remains open and never closes? I'm not sure I agree with that.

It doesn't matter if you agree or you don't, the oil thermostat is a fixed unit that opens at a preset temperature. There are no electrical parts, instead it it uses an element that when hot enough, opens a plunger and allows flow to the oil coolers. You can just buy a lower temp switch if you would like:

https://www.ecstuning.com/b-ecs-part...0743ecs09~ecs/

Originally Posted by Polo08816

I think it opens and closes repeatedly during regular operation because the factory oil cooler design is more than sufficient for normal use and even HPDE use. (I only upgraded the cooling system because the car was being shared which would result in the car being run back to back in different sessions for 50+ minutes continuous.)

It does not. These cars do run hot by design, which is more for fuel economy. The m2/3/4 all have a lower temp switch from the factory.

Originally Posted by Polo08816

Keep in mind, there are N55 cars (like my X3 35i) that do not have an oil thermostat and engine oil cooler behind the front fascia. I would submit to you that the N55 platform, in normal driving, doesn't even really require the engine oil cooler. A liquid to liquid heat exchanger with the coolant system is sufficient to keep temperatures within operating range.

The point that I'm making is that with the stock oil thermostat, a 3F difference is insignificant and if you're saying the temperatures still go to 264F-267F, then the stock oil thermostat is the limiting factor. It's very well the case that in normal use with the stock oil thermostat, someone wouldn't be able to benefit/realize the difference between a factory oil cooler and a modified oil cooler. If the thermostat decides to not flow oil, there's nothing that the factory or aftermarket cooler can do.

No.

I'm not sure how else I can explain this to you - this is not a matter of variance, we are talking about maximum allowed. As I pointed out above, once the thermostat is open, oil is flowing through the oil cooler to keep temperatures in line. This really is only applicable to high performance driving scenarios and not daily driving.

If your car is hitting 265F in oil temps, your oil is in danger of breaking down and not providing the same protection and lubrication it otherwise would have at lets say - 230F. The car will activate limp mode (cut timing, boost, and overall power) around 270F to preserve itself.

So the CSF reducing MAXIMUM temps by 3F is pathetic. It's basically doing nothing to add additional headroom for maximum temperatures.

[visionaut]

Originally Posted by Polo08816

Is your theory that once the engine reaches 250F (approximate), the stock oil thermostat remains open and never closes? I'm not sure I agree with that.

I think it opens and closes repeatedly during regular operation …

The stock oil thermostat DOES work very simply like that, it just opens when it hits temperature and then stays open. There’s no partial closing or opening - it’s binary. So it’s not a real mechanical thermostat that can continuously open/close to regulate flow and temperatures (like the Mosselman), it’s just a simple ‘valve’, once it reaches temp it fully opens and stays fully open - until the car completely cools down and then it fully closes again.

[Polo08816]

Originally Posted by AmuroRay

It doesn't matter if you agree or you don't, the oil thermostat is a fixed unit that opens at a preset temperature. There are no electrical parts, instead it it uses an element that when hot enough, opens a plunger and allows flow to the oil coolers. You can just buy a lower temp switch if you would like:

https://www.ecstuning.com/b-ecs-part...0743ecs09~ecs/


It does not. These cars do run hot by design, which is more for fuel economy. The m2/3/4 all have a lower temp switch from the factory.


No.

I'm not sure how else I can explain this to you - this is not a matter of variance, we are talking about maximum allowed. As I pointed out above, once the thermostat is open, oil is flowing through the oil cooler to keep temperatures in line. This really is only applicable to high performance driving scenarios and not daily driving.

If your car is hitting 265F in oil temps, your oil is in danger of breaking down and not providing the same protection and lubrication it otherwise would have at lets say - 230F. The car will activate limp mode (cut timing, boost, and overall power) around 270F to preserve itself.

So the CSF reducing MAXIMUM temps by 3F is pathetic. It's basically doing nothing to add additional headroom for maximum temperatures.

In a engine oil sump system that is operating correctly, that is true. I would also argue that in an engine oil sump system that is operating correctly, you'll never really exceed 265F. In fact, if your engine oil sump system has failed, your car may not actually have enough time to go into limp mode before permanent engine damage happens. This goes back to the principle that was mentioned before. The temperature readings you are seeing are just at one point at one specific time in a circuit - one specific temperature sensor. Ask me how I know.

I have RaceChrono logs to demonstrate this point at VIR back in 2021. My N55 engine oil pump failed and oil did not flow through the circuit after a certain point in time. Over the course of 1.5 laps, engine oil temps went from 220F to 290F before the engine self ventilated through the bottom. The car did NOT go into limp mode (nor was there a drivetrain malfuntion warning) before the engine seized and a rod went through the bottom despite the rise in temperature. I surmise the actual temperature at the crankshaft was way higher than the 290F it registered at the oil temp sensor because there was no oil flow at that point. This is based on the discoloration I saw in the vicinity of the crankshaft.

But if your oil sump system is functioning properly, I would submit to you that you will never see over 265F because the delta in oil temps through that circuit would be much less when there is oil flow.

Originally Posted by visionaut

The stock oil thermostat DOES work very simply like that, it just opens when it hits temperature and then stays open. There’s no partial closing or opening - it’s binary. So it’s not a real mechanical thermostat that can continuously open/close to regulate flow and temperatures (like the Mosselman), it’s just a simple ‘valve’, once it reaches temp it fully opens and stays fully open - until the car completely cools down and then it fully closes again.

I didn't say it can partially open to precisely moderate the amount of oil flow. It's binary like you said. It's either open at or beyond a pre-set temperature or it closes once it's below that threshold. I think what you are saying is that this thermostat does not close until the engine is shut down. I don't think that is the case.

And it will open and close repeatedly during regular operation. If the other cooling components could not effectively remove heat from the system without the oil thermostat being constantly open then 1) it wouldn't explain how there are other N55 platforms that do not have the air to liquid oil cooler and 2) there should not be a thermostat and it should stay open the entire time. If it was, BMW would just use this design and have constant flow: https://burgertuning.com/products/sp...l-cooler-valve

Take at look at the Mosselman thermostat site:

https://www.mosselmanturbo.com/en/msl-thermostat-n55

The Thermostat is plug-and-play and made out of a solid block of high-grade aluminum at our own facility. It is equipped with a real thermostat, not an always open solution. The oil will still reach the operating temperature at the same time as a stock thermostat.

The implication here is that the Mosselman thermostat is similar to the factory thermostat - it will just open at a lower temperature and close once below that lower temperature. It, like the factory thermostat, is not an ALWAYS open solution like the BMS sport oil cooler valve.

[AmuroRay]

Originally Posted by Polo08816

In a engine oil sump system that is operating correctly, that is true. I would also argue that in an engine oil sump system that is operating correctly, you'll never really exceed 265F. In fact, if your engine oil sump system has failed, your car won't actually have enough time to go into limp mode before permanent engine damage happens. This goes back to the principle that was mentioned before. The temperature readings you are seeing are just at one point at one specific time in a circuit - one specific temperature sensor. Ask me how I know.

I have RaceChrono logs to demonstrate this point at VIR back in 2021. My N55 engine oil pump failed and oil did not flow through the circuit after a certain point in time. Over the course of 1.5 laps, engine oil temps went from 220F to 290F before the engine self ventilated through the bottom. The car did NOT go into limp mode (nor was there a drivetrain malfuntion warning) before the engine seized and a rod went through the bottom despite the rise in temperature. I surmise the actual temperature at the crankshaft was way higher than the 290F it registered at the oil temp sensor because there was no oil flow at that point. This is based on the discoloration I saw in the vicinity of the crankshaft.

But if your oil sump system is functioning properly, I would submit to you that you will never see over 265F because the delta in oil temps through that circuit would be much less when there is oil flow.

https://f87.bimmerpost.com/forums/sh...3&postcount=64

Originally Posted by ZM2

Hey guys, thought I'd update the thread with this year's open track battle observations.

Max temps:
Ambient - 95F
IAT - 155F
Oil - 270F
Coolant - 256F

IATs were 10F lower than last year but matched ambient being 10F lower, as well. Oil/coolant max temps were similar to last year.

Clearly there is an effective limit to how much heat the stock oil cooler can reject - the same principles work for an intercooler and radiator. When they exeed their ability to reject heat, they get heat soaked and continue to rise in temperature.

Originally Posted by Polo08816

I didn't say it can partially open to precisely moderate the amount of oil flow. It's binary like you said. It's either open at or beyond a pre-set temperature or it closes once it's below that threshold. I think what you are saying is that this thermostat does not close until the engine is shut down. I don't think that is the case.

No one said this.

Originally Posted by Polo08816

And it will open and close repeatedly during regular operation. If the other cooling components could not effectively remove heat from the system without the oil thermostat being constantly open then 1) it wouldn't explain how there are other N55 platforms that do not have the air to liquid oil cooler and 2) there should not be a thermostat and it should stay open the entire time.

Other "high performance" variants of the N55 DO have these systems, including my M235i F2X and Msport F3Xs.

Originally Posted by Polo08816

If it was, BMW would just use this design and have constant flow: https://burgertuning.com/products/sp...l-cooler-valve

Take at look at the Mosselman thermostat site:

https://www.mosselmanturbo.com/en/msl-thermostat-n55

Why would the circuit need to always be open? As I stated above, the oil needs to reach an operating temperature (combined with specific oil formulations) for adequate flow and lubrication. The standard thermostat on non M cars is set to open at a higher temperature for fuel economy.

[Polo08816]

Originally Posted by AmuroRay

https://f87.bimmerpost.com/forums/sh...3&postcount=64

Clearly there is an effective limit to how much heat the stock oil cooler can reject - the same principles work for an intercooler and radiator. When they exeed their ability to reject heat, they get heat soaked and continue to rise in temperature.

From just that post it appears as if he added a radiator to his setup but noted that the max temps he experienced didn't change - which indicates that he didn't exceed the capabilities of what he already had in place. He mentioned that the temperatures were slower to increase, which makes sense if your system contains more of the same fluid - additional heat capacity.

One thing to keep in mind about adding fluid (like I did in the case of the CSF engine oil cooler - 0.5 quarts) is that you're increasing the length of the plumbing. This increases the work that the fluid pump has to do to cycle fluid in that circuit. How much more work? I couldn't tell you with any specificity. What I can tell you is that my car won't go back on track without the M2 N55 / S55 oil sump retrofit that adds an additional pump and pickup tube to the oil pan.

Originally Posted by AmuroRay

No one said this.

Originally Posted by visionaut

The stock oil thermostat DOES work very simply like that, it just opens when it hits temperature and then stays open. There’s no partial closing or opening - it’s binary. So it’s not a real mechanical thermostat that can continuously open/close to regulate flow and temperatures (like the Mosselman), it’s just a simple ‘valve’, once it reaches temp it fully opens and stays fully open - until the car completely cools down and then it fully closes again.

Originally Posted by AmuroRay

Why would the circuit need to always be open? As I stated above, the oil needs to reach an operating temperature (combined with specific oil formulations) for adequate flow and lubrication. The standard thermostat on non M cars is set to open at a higher temperature for fuel economy.

It wouldn't. That's my point.

[AmuroRay]

Originally Posted by Polo08816

From just that post it appears as if he added a radiator to his setup but noted that the max temps he experienced didn't change - which indicates that he didn't exceed the capabilities of what he already had in place. He mentioned that the temperatures were slower to increase, which makes sense if your system contains more of the same fluid - additional heat capacity.

Pleas stop moving the goalposts - you said that the oil should not exceed 270F on a functioning system - and it clearly has. The system has limits on how much heat it can reject, and the CFS barely raises these limits.

The Do88 unit was promising (thread linked) that when it was combined with the lower temperature thermostat, never allowed heat to overwhelm the system. Again, the flimsy CSF unit could not do that.

[rlesko]

Originally Posted by AmuroRay

You can just buy a lower temp switch if you would like:

https://www.ecstuning.com/b-ecs-part...0743ecs09~ecs/

Do you know anyone who has experience with this?