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

GrazieVale

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First of all thanks for the knowledge acquired by reading the entire thread.
Started with a question that's not been touched (imagine that) which is in a e92 m sport I'm thinking of upgrading the oil cooler, the main radiator with a csf one and on the passanger side I'm in the fence between a trans cooler or an auxiliary radiator (both as big as possible). It crossed my mind to just do both but might save that if v1 doesn't work as intended.
Frequent mountain and and track use of course.

Thanks again guys.
First of all thanks for the knowledge acquired reading by reading the entire thread.
Started with a question that's not been touched (imagine that) which is in a e92 m sport I'm thinking of upgrading the oil cooler, the main radiator with a csf one and on the passanger side I'm in the fence between a trans cooler or an auxiliary radiator (both as big as possible). It crossed my mind to just do both but might save that if v1 doesn't work as intended.
Frequent mountain and not and track use of course.

Thanks again guys.
E92 335i auto
 

Asbjorn

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For frequent track use you will have cooling bottlenecks coming up in the following order.
  • First your iats will rise, causing timing corrections. Use a map that is one step below the fuel you use (for example use a RON95 map if RON98 is available). Use an FMIC with double the frontal area or more compared to stock. Cooling area is what matters, not depth, and the same will be true for the other coolers/radiators.
  • Next your coolant temp will miss its target. Target will be at 95C or lower depending on your tune and ambient when high+kft is enabled (which it will be after a few WOT events). You will most likely start to see +100Cs coolant temps during the summer which is already above target. I recommend setting the yellow warning trigger to somewhere around 110C, instead of the stock 118C in your map. This gives you enough headroom for some pushing, while still getting a warning early enough that your radiators are struggling. And please dont buy the CSF radiator. Its barely an upgrade at all, it will most likely start leaking over time and the cost is just way too high for what you get. Spend the money on upgrading the aux radiator instead. And please know that no matter what you do, you will never get enough radiator + air flow for any serious track use when it gets hot and humid outside. The core problem being that there just isnt enough space anywhere for the radiator frontal area you actually need. What do you need you ask? Probably around 50% more than stock. The S55/S58 shows the solution: Use a flat oil cooler + a2w intercooler system. This just isnt happening on our cars.
  • Finally your engine oil temps and gearbox oil temps will start to suffer, oh and lastly the differential if you run an LSD. I was able to solve the DCT oil temp cooling on my car with the ssp set. It actually works and keeps DCT temps in check if the cooler is placed correctly. Even though I was not able to solve the water cooling bottleneck with my car, at least it gave some piece of mind that the DCT wasnt overheating. OK, how about the engine then? Well, upgrading the engine oil cooling is risky. So many people have had oil lines burst and what not. Its hard to recommend touching it, and you will still have the coolant cooling and also oil pressure problems anyway. None of those problems have been solved with standard aftermarket solutions. However the S55 solved all of those problems, at least with stock power/tune. With higher power it problem has a bottleneck in the iat department.
So all in all, if you are serious about frequent track use, I recommend just getting an S55 engine instead. For mountain driving, you dont need to touch anything really. Just lower the limits in the map, cool down a bit if you see a yellow warning, and otherwise enjoy the car. Oh and don't forget to use some serious high temp brake pads for those downhill sections. You dont need a BBK, just some high temp pads.
 
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GrazieVale

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Jan 26, 2022
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Thanks for the nice reply.Have made my mind and decided to go with a small trans cooler in front of the radiator,bigger engine oil cooler on the right side and auxilliary radiator on the left side but so far could only find the oem one. Does the 5 series fit with some trimming or you can point me another one.
The csf to me just the side tanks worth the money and it will help something even if not much.
 

Asbjorn

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Thanks for the nice reply.Have made my mind and decided to go with a small trans cooler in front of the radiator,bigger engine oil cooler on the right side and auxilliary radiator on the left side but so far could only find the oem one. Does the 5 series fit with some trimming or you can point me another one.
The csf to me just the side tanks worth the money and it will help something even if not much.
Sounds fair to me. The CSF lasted me almost 3 years before it started leaking. Now back to oem-type. Just fyi.

As for a larger AUX rad, basically ppk is the only option, which isn't cheap. There's no proper ppk++ PnP solution on the aftermarket for N54 afaik. I had everything custom made based on recommendations from spoolstreet, but its not something I would recommend doing outside China.
 
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JohnDaviz

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There's no proper ppk++ PnP solution on the aftermarket for N54 afaik.

I bought an additional electrical waterpump from Bosch together with a PWM module to control the 535D/M4 cooler. I was also looking for some kind of PPK+ integration.

But now as you wrote. Ppl may check if the actual M4/535D/M5 hoses which run to and from cooler to cooler to pump etc may fit into the E9x.

1644391315966.png


I think it is possible to copy the S55 design. The major challenge is to relocate the water hoses to the heater radiator in the HVAC prior to add the connect the aux radiator to Hose no. 5.


It is not close to a plug and play solution.

For track use i think going the whole S55 fmic retrofit is your best bet. On the E9x you don´t have really a lot of room in the front as you do on the Z4. By changing to the A2W intercooler you get a lot of space in front of the main radiator.

Now you have the space to add a taller main radiator as the stock one is limited in height due to the fmic sitting below.

You now can swap the S55 oil cooler plug and play as the oil filter housing looks identical to the N54/55:
1644392592928.png


Even the transmission oil cooler for DCT cars looks feasible now so you would have no coolers other than the aux rads on the driver and passenger side anymore:
1644392783962.png
 
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GrazieVale

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Jan 26, 2022
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But might do it in stages.
First the big aux radiator on the driver, bigger oil cooler on the passanger side and a trans cooler somewhere to be determined, see the results and then go the a2w and big main radiator route which I think it's a great and feasable idea.
 
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Asbjorn

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The data I have seen from track-going S55 engines shows that while water and oil is fine, the a2w is a bottleneck when running stg 2. Not sure about stock power, but I guess it should be fine for that. The M4 GT4 uses the same cooler afterall.

Anyhow you dont have to use an S55 sized cooler. You could use something larger like the S58 type instead depending on your power level.
 
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JohnDaviz

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So far on my list is the stock E92 M3 Watercooler (higher because no FMIC below) or the here in germany widely used do88 part.
I wasn´t sure which heat exchanger to use yet but a bigger one was also on my research list. I will check the s58 one.
What i like about the s55 heat exchanger is that 99% oem hoses and plugs can be used. Need to check if this will be the same with the s58 heat exchanger.

Did you mean by cooler the S58 a2w cooler also or primarily?

What i find extremely interesting is that there is a huge A2W intercooler on Ali:

It is WAY bigger than the stock or usual aftermarket parts. But it may not fit anymore under the stock hood.

edit:
S58 a2w intercooler doesn´t look bigger and is probably impossible to swap onto the n54
BMW-S58-engine-1.jpg
 
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Asbjorn

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So far on my list is the stock E92 M3 Watercooler (higher because no FMIC below) or the here in germany widely used do88 part.
I wasn´t sure which heat exchanger to use yet but a bigger one was also on my research list. I will check the s58 one.
What i like about the s55 heat exchanger is that 99% oem hoses and plugs can be used. Need to check if this will be the same with the s58 heat exchanger.

Did you mean by cooler the S58 a2w cooler also or primarily?

What i find extremely interesting is that there is a huge A2W intercooler on Ali:

It is WAY bigger than the stock or usual aftermarket parts. But it may not fit anymore under the stock hood.

edit:
S58 a2w intercooler doesn´t look bigger and is probably impossible to swap onto the n54

oh I meant the center radiator/cooler for the a2w system. I believe the center one is larger on the S58. The aux one is probably the same.

BTW I found the S55 iat data I posted: https://www.spoolstreet.com/threads/n54-water-to-air-intercooler-street-build.3516/post-104468

It's also worth noting that the S55 GTS had water injection, which is perhaps another indicator that they knew there was an iat cooling bottleneck at higher power modes.
 

JohnDaviz

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oh I meant the center radiator/cooler for the a2w system. I believe the center one is larger on the S58. The aux one is probably the same.

Seems there is not a huge difference but the s58 seems to be nearly an inch taller.
I would say width and thickness are neglectable.

S55 (17112284608) - 31.2 x 30.3 x 7.2 inches
S58 (17119468695) - 30.9 x 31.2 x 7.4 inches
 

Asbjorn

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While I did not measure the cooler, I did measure the main S55 engine radiator to be 57cm x 49cm x 3cm (22in x 19in x 1.2in). On the S55 the cooler for the intercooler is clearly not the same height as the radiator. It is shorter as can be seen below.

On the other hand, the S58 cooler does look like it is the same height as the main radiator, again see pictures below. They even had to move the dct cooler to a third layer.

I also note that both systems use around 4L of coolant, but the S58 uses a 130W electric pump compared to 80W for the S55. Finally it says that both engines feature an indirect charger air cooler with a cooling power of 36kW. This supports what you said about the units looking similar in size.

S58:

1645003823772.png



S55:

1645003907971.png
 

JohnDaviz

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I will check but i think it is safer to use the E92 M3 main water cooler.

It is 60cm x45.4cm x 32cm

Basically plug and play except it is reaching lower where the FMIC was before that.
 
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