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

RSL

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Not sure I follow 100%...

You are saying "retro fit" the s55 intercooler to allow me to use a longer radiator. I'm not sure what you mean by "then use a charge air radiator that is large and flat."
I assume he's alluding to heat exchanger for A2W IC (thin) and remove FMIC and associated 3" piping to free up room up front.

Someone has recently done S55 A2W IC on N54 themselves though, thread is here somewhere.

S55 oil cooler has a target painted on it for debris, but might be something to consider.
 
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RSL

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It was @bantam lol

 
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NoQuarter

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The A2W intercooler wouldn't be suitable for such extended track use would it? Just even more water to try and cool down just so it can cool down the air?
 

bantam

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The A2W intercooler wouldn't be suitable for such extended track use would it? Just even more water to try and cool down just so it can cool down the air?

My thinking is that it does not seem like the m3/m4 guys are having significant trouble with their cars overheating on road courses (not thoroughly researched, I just have not heard of any issues).

While it is true that you are adding another boundary for heat transfer, the thought is that you are more effective at both of those boundaries.
 
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Asbjorn

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My thinking is that it does not seem like the m3/m4 guys are having significant trouble with their cars overheating on road courses (not thoroughly researched, I just have not heard of any issues).

While it is true that you are adding another boundary for heat transfer, the thought is that you are more effective at both of those boundaries.

It certainly makes sense to have two large thin radiators sitting in front of each other, instead of having two thick ones sitting in parallel. Because one is low temp and the other high. And you just have more space for larger coolers in general with the A2W setup.

However, while the S55 certainly has better coolant cooling, it is not immune to iat-related power reduction.

From https://f80.bimmerpost.com/forums/showthread.php?t=1003735

Here's how the S55 performs on dyno if you do consecutive pulls. In its defence though, this is probably a worse scenario than anything you would ever experience on track.

24467



In comparison, my car starts to pull timing above iat 130F as a preventive measure, and in the case of my 7in FMIC (non-HD) it mainly affects the end of very long straights (going from 3rd though 5th) in 25C weather if you look in the log I posted.

Just for fun, I tried comparing the virtual dyno curves of the very first WOT pull on track against the very last. I took out the 4th gear rpm range and deleted everything else. During the first 4th gear pull, the car saw 212F coolant and 111F peak iat. During the last it was 223F coolant and 133F peak iat. Also, during the last pull, timing was down by 2-3 degrees, and boost was up 1psi.

Here's the result - a difference of 0-15hp depending on rpm. However, it should be noted that this track is basically two long straights with some lower speed cornering in between. Other tracks may have a slightly higher percentage of wot per lap and a lower average speed.


24468


Since the S55 cooling system is used in the M4 GT4 (with the exception of the DCT cooler, which is from the dct M5/M6) I think it is fair to say it is track-ready, and great inspiration for those of us (read: me) running similarly low power levels. Another point of reference is the N55 powered M2 which also features upgraded coolant cooling, semi-dry oil sump etc but with a traditional FMIC.

EDIT: I talked to some M4 track-junkies here in China and Im told their coolant temps seem to stay below 95C on track, even in hot weather. I am also told that 106C is not a problem with most newer engines from germany...
 
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shushikiary

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Do you have any details on that semi-dry oil sump you've referred to a few times? I took a glance at your build page but didn't see anything on it. Are you just talking about an oil pan baffle or did you actually put in a different oil pump?
 

Asbjorn

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Do you have any details on that semi-dry oil sump you've referred to a few times? I took a glance at your build page but didn't see anything on it. Are you just talking about an oil pan baffle or did you actually put in a different oil pump?

Please look at the table in the first post on my build thread. There's a description and links to pictures and other threads on the topic.

24490
 

MDORPHN

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Just analyzed those portions of a MHD log on two sections of Summit Point from a 25 minute track session on a very cold, 41F day.

I'm now running a CSF radiator and my coolant temps were remarkably stable, running between 183 - 189F on those two parts of the track where I was WOT and saw highest boost (ranging from 19.7 - 21.3 psi on my single turbo). However, my IAT rose steadily during the session, increasing from 20F over ambient at the start to 65F over ambient at the end of the session.

My best guess (informed by discussion with Barry at 3DM) is that this rise is due to heatsoaking of the upper stepped portion of the intercooler that is out of the airflow, behind the bumper cover. I'm now considering replacing it with a non-stepped intercooler like the 7" VRSF race, but would welcome advice about other similar designs that I should consider.

Neil
 
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Asbjorn

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Just analyzed those portions of a MHD log on two sections of Summit Point from a 25 minute track session on a very cold, 41F day.

I'm now running a CSF radiator and my coolant temps were remarkably stable, running between 183 - 189F on those two parts of the track where I was WOT and saw highest boost (ranging from 19.7 - 21.3 psi on my single turbo). However, my IAT rose steadily during the session, increasing from 20F over ambient at the start to 65F over ambient at the end of the session.

My best guess (informed by discussion with Barry at 3DM) is that this rise is due to heatsoaking of the upper stepped portion of the intercooler that is out of the airflow, behind the bumper cover. I'm now considering replacing it with a non-stepped intercooler like the 7" VRSF race, but would welcome advice about other similar designs that I should consider.

Neil

Last week my iat peaked at 151F (80F over ambient) during my track session running the 7" non-HD. No difference between the first and last laps. 18-20psi on GC lites.

When I ran the 7.5 HD last summer, I saw peak iat of 143F (50F over ambient) on the third and last lap with that FMIC. It may have gone higher, if I had continued. Unfortunately I dont have more data than that. On the Z4, the 7.5 is not covered by the bumper as much as on the 1/3 series.

If you install the 7 HD, I would guess your results would fall somewhere between your current car's and mine. I certainly want that FMIC, as I no longer have space for the 7.5. Unfortunately it isn't produced in China, and it is a hassle to import. As for you, I would stick with the 7.5 HD or go custom. Very custom.
 

MDORPHN

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Just analyzed those portions of a MHD log on two sections of Summit Point from a 25 minute track session on a very cold, 41F day.

I'm now running a CSF radiator and my coolant temps were remarkably stable, running between 183 - 189F on those two parts of the track where I was WOT and saw highest boost (ranging from 19.7 - 21.3 psi on my single turbo). However, my IAT rose steadily during the session, increasing from 20F over ambient at the start to 65F over ambient at the end of the session.

My best guess (informed by discussion with Barry at 3DM) is that this rise is due to heatsoaking of the upper stepped portion of the intercooler that is out of the airflow, behind the bumper cover. I'm now considering replacing it with a non-stepped intercooler like the 7" VRSF race, but would welcome advice about other similar designs that I should consider.

Neil

Today was much warmer -- 61F -- on track. 20F warmer than yesterday.

I haven't yet reviewed logs, but my MHD display indicated that coolant temps went up to 212F, 23F higher than yesterday. And the IAT went up to 136F, 75F over ambient (a 10F greater rise over ambient than yesterday).

I'll post more once I've had a chance to review the logs.

Neil
 

Asbjorn

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Today was much warmer -- 61F -- on track. 20F warmer than yesterday.

I haven't yet reviewed logs, but my MHD display indicated that coolant temps went up to 212F, 23F higher than yesterday. And the IAT went up to 136F, 75F over ambient (a 10F greater rise over ambient than yesterday).

I'll post more once I've had a chance to review the logs.

Neil

Here, 1C warmer, 28.5C vs 27C last time (indicated by cluster). So 83F ambient. Peak iat was 73C / 163 F (80F over ambient), peak coolant 109C / 228F, peak oil 134C / 273F

These peaks happened yesterday during two hot laps. Here's the log which includes two hot laps and two cool down laps.

 

Asbjorn

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I tried setting up my additional cooler in series instead of parallel, using hoses with a larger ID. We also modified the front to force more air through the coolers. However today's track logging showed no change at all. It was around 2C hotter compared to last time, and coolant was peaking 1-2C higher.

Here's a 3min log (two hot laps) starting right after a cool down lap.


24763


So to clarify, I am currently running the CSF AT radiator, data from Barry
Core width: 24"
Core height: 15"
Core Thickness: 1.66"
Total: 360 x 1.66"
(How big the AT core is, I do not know, lets assume 20-30%)

As well as an additional radiator (my data)
Core width: 22"
Core height: 13"
Core Thickness: 1.57"
Total: 286 x 1.57"

So if we assume 20%-30% of the CSF radiator is used for AT, the additional radiator basically almost doubles the thickness of the engine coolant core.
Another way to put it: If we imagined I was running a CSF MT radiator, my setup corresponds to adding 0.75in of thickness to that radiator. Calculated like this (1.66x0.7+286/360x1.57)-1.66.

What I could do is order a new custom additional radiator which is thicker (52mm) and wider (24in vs 22in). This would result in 312 x 2.05, which is an increase in volume of 40% for the additional radiator, and an increase of 20% for the entire system, again assuming the AT core is 20-30% of the CSF radiator.

Problem is, the additional radiator is sitting in front of the other, so the volume increase is entirely added thickness, not area. And I am afraid I have already exceeded the radiator volume of an M4, which has no coolant temp issues? It is hard to find the exact M4 radiator dimensions online though (both of them).

Edit:

Just checked the repair instructions for N54 vs S55 to find how much coolant is needed:
N54 AT: 8.4L https://www.newtis.info/tisv2/a/en/...anuals/17-cooling/17-00-cooling-check/6v2hM1N
S55 AT: 13.9L https://www.newtis.info/tisv2/a/en/...als/17-cooling/17-00-cooling-check/1VnXwYY3hf
Mine: 11L (not sure if engine was completely drained, but that is how much we had to put in)

For fun I also checked these
S54: 10L https://www.newtis.info/tisv2/a/en/...anuals/17-cooling/17-00-cooling-check/5v1SCB6
B58: 10.5L https://www.newtis.info/tisv2/a/en/...als/17-cooling/17-00-cooling-check/1VneEOHc5T
 
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aus335iguy

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If my memory serves me correctly the M3 DSC will send a signal to the DCT to release both clutches mid corner to aide stability.
 

MDORPHN

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Today was much warmer -- 61F -- on track. 20F warmer than yesterday.

I haven't yet reviewed logs, but my MHD display indicated that coolant temps went up to 212F, 23F higher than yesterday. And the IAT went up to 136F, 75F over ambient (a 10F greater rise over ambient than yesterday).

I'll post more once I've had a chance to review the logs.

Neil

Just reviewed data and pretty much confirmed the above. Again, ambient was 61F, 20 degrees higher than yesterday.

Boost ranged from 21.0 - 23.4 psi. Boost was higher than yesterday because there was more grip -- as track was warmer -- and I was heavier on the throttle.

Coolant temps 192F - 210 F. They ranged 183F - 189F yesterday.

IATs rose from 104F to 136F at end of session, or 75F over ambient. Yesterday, peak was 65 degrees over ambient.

Neil
 
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Torgus

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While I understand the argument of the 7.5 race IC heat soaking at the top as there is basically no air flow on the top 1/3, does the IC not act like one large heatsink at the end of the day? I would think larger and increased total mass of the 7.5 race IC would still be a better choice vs the 7'' HD. Be curious to hear your thoughts.


While the space is small I wonder if you could duct any air from above the brace down? Almost like where the plastic in the pic below is curved up?

I see no reason to keep that rubber that blocks the radiator, that part that kind of mimics the front kidney bean grills. I hope everyone removes this when they do their IC install or at least cuts the middle part out:
24774

Not my pic btw ;)
 
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MDORPHN

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While I understand the argument of the 7.5 race IC heat soaking at the top as there is basically no air flow on the top 1/3, does the IC not act like one large heatsink at the end of the day? I would think larger and increased total mass of the 7.5 race IC would still be a better choice vs the 7'' HD. Be curious to hear your thoughts.


While the space is small I wonder if you could duct any air from above the brace down? Almost like where the plastic in the pic below is curved up?

I see no reason to keep that rubber that blocks the radiator, that part that kind of mimics the front kidney bean grills. I hope everyone removes this when they do their IC install or at least cuts the middle part out:
View attachment 24774
Not my pic btw ;)

The theory is that the upper portion of the intercooler does not get any airflow and, as a result, heat soaks. So the cooler air from the lower portion mixes with the hotter air from the upper area resulting in higher IATs. And yes, agree about cutting out that rubber shrouding.

Neil
 

Torgus

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The theory is that the upper portion of the intercooler does not get any airflow and, as a result, heat soaks. So the cooler air from the lower portion mixes with the hotter air from the upper area resulting in higher IATs. And yes, agree about cutting out that rubber shrouding.

Neil

I just wondered how much thermal transfer there was along the IC as it is all physically connected. With some thermal couples it would be interesting(to me) to see how much or how little there is.
 

MDORPHN

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I just wondered how much thermal transfer there was along the IC as it is all physically connected. With some thermal couples it would be interesting(to me) to see how much or how little there is.

Agree. I imagine that the entire housing heats up as a result of the uncooled air from the portion of the intercooler that is not in the air flow.

Neil
 

fmorelli

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While the space is small ...
I gotta say ... for all the every-so-slight differences the Z4 has (N54 long block and everything else about the car is a slightly varying headache to an E90 or E82) ... and those differences are a royal PITA, trust me ... I gotta say I have a cavern of frontal space and airflow compared to the E90 or E82 and ... beside a low CoG don't have much else to be thankful for ... but thankful for that! lol

Filippo
 
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