N54 Cooling - Temp Control Logic and what are your temps during extended track use?
- Thread starter barry@3DM
- Start date
Big picture guys, big picture now!
Biggest problems with the stock setup:
1) coolant - by far the biggest issue, especially on DCT cars
1.5) brakes
2) iat - obvious, although not a game stopper
3) engine oil - this is the third bottleneck
4) transmission temp (dct) - when all of the above are kept from going through the roof, this one will start doing so.
5) tires
5.5) the driver
6) dampers overheating?
8) differential (not confirmed, just my theory)
17) thermostats
145) whether to use 8an or 10an thermostats...
There's really almost nothing gained from lowering the engine oil temp set point or deleting it. It is like using MHD track mode, or running a thicker radiator as I tried... It merely delays the problem, and it comes with a bunch of cons on the road. If your cooling system is big enough for the power and ambient temps, stock thermostat setpoints are fine. Or in other words, if your problem is that your oil exceeds xxx temp on track, then it will also exceed xxx minus whatever you lower the set point to. Lowering the setpoint doesn't magically increase cooling capacity in the long run (ie more than half a lap)
Pushing the oil thermostat wide open and installing an extra oil cooler to the oil pan with its own pump was literally the first thing I did on my car, and I would hit power reduction due to 118C coolant in less than two laps in +100F ambients.
Please consider enlarging the stock location oil cooler and then focus on increasing radiator area instead of spending money on thermostats.
Agreed!
If you increase power, you must also increase cooling. Auxiliary radiators of sufficient size, area, heat removal ability, etc. are clearly required. Do whatever you can with auxiliary radiators to keep the coolant no higher than 100C with at least one good oil cooler and you’ll solve this and enable N54-powered track cars to really become a thing.
You’ve done lots of cooling iterations on the front of your car. I’m wondering given the space limitations whether an auxiliary coolant radiator and fan can be placed somewhere underneath and/or in the rear end of the car, with a sufficient auxiliary coolant pump.
Now it is cross flow, thanks for the recommendation.
Well it is a good idea. I will try the new setup first before considering what you said. We have also added outside 200psi water mist spray to see if that makes any difference.
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Speaking of oil thermostats: Just stumbled upon this old post. Does anyone know if the S55 thermostat bolts on the N54? It is said to open 10 degrees earlier, and is obviously designed for the huge S55 oil cooler. Might be a good alternative to those in here who believe in thermostat mods, and do not want to convert to AN.
Most cores and kits with no compromise on other platforms are bigger. The only reason I could see this being the case on this car is easier to route lines. Smaller OD hoses are easier to radius.
Couldn't find anything about "too large". The pressure drop along isn't as significant as 2x oil coolers in series. That calculation becomes harder with all the angled fittings. I could've made -10AN fit so easy with tighter radius hose ends. The external thermostat had to go, way too painful with dual cores than a single.
This car will never see slicks, never see sprint race nor endurance. T/A style only.
Deleting thermostat is a moot issue for me. My car takes 15-20mins to warmup with or without it, deleting it made no difference to warmup with my style of driving to and from local places: low speed, low airflow start/stop. In 1C ambient temperature during a road trip inland, it was still only 50C after 15min stationary. This would've been the case with or with a thermostat. When the car is stationary, it's just oil capacity. It's not providing any cooling.
On my car, I tape the fronts in low ambient temp which we barely experience here. I only did it when I saw temps drop from 90C to 70C on the fwy at close to freezing temps. I might add the mosselman thermostat or similar later solely for quality of life and that's it. My cooling maps are completely standard.
Obv with so many varibales, YMMV. If anyone gets the S55 thermostat housing, compare the elements inside. That engine along with the B58 doesn't budge from 110C out of the box. Who knows once they also add more grip let alone power.
Anyway, this solution works for me. Lets see when the car is unleashed with full solid/spherical rear end, 2-way clubsports and some semi-slicks.
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So I finally got to do some logging with the new cooling setup on track in 90F ambient
1) Everything turned on (oil cooler #2 pump on, aux rad #2 valve open, water spray, water injection, A/C off)
Peak iat: 122F
Peak coolant: 221F
Peak DCT: 216F
Peak oil: 266F
Pretty happy with these numbers overall
2) Aux radiator number 2 valve closed, everything else on:
I wanted to see if the aux radiator behind the FMIC would influence iat and/or water temp somehow, but only got one lap in
Peak iat: 115F (no major difference)
Peak coolant: 219F (no major difference)
Peak DCT: 214F
Peak oil: 261F
Seems turning the 2nd aux radiator off doesn't improve iat, which is good.
3) Aux 2 closed, water spray off, oil cooler number 2 pump off, water injection still on:
Peak iat: 124F
Peak coolant: 223F
Peak DCT: 212F (seems turning water spray off did not change much here)
Peak oil: 271F (additional oil cooler does seem to make a difference)
Seems external water spray doesn't do much. It might help water temps a bit, or maybe that was just the aux radiator being turned off. However the extra oil cooler seems to be helpful.
4) as 3) but with water injection off
Peak iat: 134F (seems water injection does make a difference)
Peak coolant: 223F
Peak DCT: 208F
Peak oil: 268F (additional oil cooler still seems to make a difference)
Only did one lap due to red flag.
So here we see that water injection is indeed helpful.
1) Everything turned on (oil cooler #2 pump on, aux rad #2 valve open, water spray, water injection, A/C off)
Peak iat: 122F
Peak coolant: 221F
Peak DCT: 216F
Peak oil: 266F
Pretty happy with these numbers overall
2) Aux radiator number 2 valve closed, everything else on:
I wanted to see if the aux radiator behind the FMIC would influence iat and/or water temp somehow, but only got one lap in
Peak iat: 115F (no major difference)
Peak coolant: 219F (no major difference)
Peak DCT: 214F
Peak oil: 261F
Seems turning the 2nd aux radiator off doesn't improve iat, which is good.
3) Aux 2 closed, water spray off, oil cooler number 2 pump off, water injection still on:
Peak iat: 124F
Peak coolant: 223F
Peak DCT: 212F (seems turning water spray off did not change much here)
Peak oil: 271F (additional oil cooler does seem to make a difference)
Seems external water spray doesn't do much. It might help water temps a bit, or maybe that was just the aux radiator being turned off. However the extra oil cooler seems to be helpful.
4) as 3) but with water injection off
Peak iat: 134F (seems water injection does make a difference)
Peak coolant: 223F
Peak DCT: 208F
Peak oil: 268F (additional oil cooler still seems to make a difference)
Only did one lap due to red flag.
So here we see that water injection is indeed helpful.
In the afternoon I turned everything on again, refilled fuel and water, and swapped from MHD to my AiM device to get some actual track practice done for once. I managed to do five laps until I ran out of brakes (pedal started going soft). My brake fluid is around 9 months old, so that was to be expected I guess. Anyway here are some selected channels from the AIM:
Unfortunately the device only logs water and oil temps, but I am pretty happy with these numbers given the ambient temps. Power was definitely holding much better than previously due to the lower iats. But I have an issue with afrs going rich post shift that I need to look into.
Anyhow, my friends M2 (N55) could only do one hot lap, then the DCT overheated. They say this is a common issue even for M4s at this track in this weather. I guess there's a reason the M4 GT4 uses the M6 dct cooler.
Unfortunately the device only logs water and oil temps, but I am pretty happy with these numbers given the ambient temps. Power was definitely holding much better than previously due to the lower iats. But I have an issue with afrs going rich post shift that I need to look into.
Anyhow, my friends M2 (N55) could only do one hot lap, then the DCT overheated. They say this is a common issue even for M4s at this track in this weather. I guess there's a reason the M4 GT4 uses the M6 dct cooler.
One day I'll have a proper logging setup that isn't a huge pain in the ass to deal with on track, but, thought I'd update that, with the addition of a center hood vent and the smaller CSF intercooler (compared to the massive VRSF 7.5"), paired with a full front splitter that's fully covered the bottom of the front-end and is now forcing all the air to go through the bumper, my temps have been awesome.****
I have my water pump set to Track in MHD, custom tune by Wedge, running E40 on stock turbos around 17-18psi. Oil temps haven't gone above 250* and I ran in 99* heat yesterday at Chuckwalla for 15-20 minutes straight.
****editing for @Asbjorn **** I do not have any hard data other than knowing my oil temps weren't exceeding 250*, with no warning lights for water temps, no power reduction, and no limp mode. In my 4+ years of experience racing with this motor, I can confidently say there has been a massive improvement in the heat dissipation of this setup, but I will follow up with logs at the next track day so as not to steer the community along a path of lies and deception.
Just a refresher on my setup:
CSF Radiator (OEM coolant)
CSF intercooler
Twin Setrab 19-row oil coolers, no thermostat, running in sequence
Ravenol 5w-40
Stock turbos with bolt-ons
I have my water pump set to Track in MHD, custom tune by Wedge, running E40 on stock turbos around 17-18psi. Oil temps haven't gone above 250* and I ran in 99* heat yesterday at Chuckwalla for 15-20 minutes straight.
****editing for @Asbjorn **** I do not have any hard data other than knowing my oil temps weren't exceeding 250*, with no warning lights for water temps, no power reduction, and no limp mode. In my 4+ years of experience racing with this motor, I can confidently say there has been a massive improvement in the heat dissipation of this setup, but I will follow up with logs at the next track day so as not to steer the community along a path of lies and deception.
Just a refresher on my setup:
CSF Radiator (OEM coolant)
CSF intercooler
Twin Setrab 19-row oil coolers, no thermostat, running in sequence
Ravenol 5w-40
Stock turbos with bolt-ons
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How do you know your temps were great if you don't have any data on the coolant temps? When I was running the larger dual oil coolers without thermostat and csf rad only I would see coolant well above 110C, while oil was below 125C.
When you run no thermostat and track setting in mhd, your oil will start at a very low temp level, and coolant might hit the roof way before oil without you knowing it, simply because it takes much longer time for oil to heat up. I dropped that setup because logging eventually showed water was a much bigger issue than oil temps.
btw I love how you are scooping in air with that setup.
Pretty easy to know I don't have a coolant problem since I'm not hitting limp mode or having the water temp warning coming on. I'm a big fan of data too, and that's why I prefaced the post to say I have no numbers, but after three years of track abuse, limp modes and warning lights, my issues are gone. I'll get a log at the next track day once I've switched the phone logging since it'll be easier to mount than the tablet.
Oh you can hit power reduction at 118C water temp and no lights will come on. I also thought we established it was better to stay out of the 110C - 117C range even though it wont cause any modes or lights except timing reduction (depending on iat)? This just to keep the bananas away.
Anyway you can't really state your temps are great without data to prove it. Sorry for being that guy this time.
You can be whatever guy you set out to be bud.
You're acting like I made a massive claim and said that data was stupid. Again, I said I don't have logs from this day, and I have nothing to prove, but I have a shit-ton of experience driving this motor on track and I can tell you that everything has been perfect for the last two track days in Southern California heat. Again again, I'll take some logs next go-round to show you. Take my word for it or be suspicious, all good either way.
Stating that your temps are great on track in 99F heat is indeed world breaking news. A huge claim. It has never been achieved with the N54 to my knowledge, and certainly not with just one tiny csf radiator.
I think he was referring to the front splitter which is sealed to the bumper. In this fashion, it also serves as an air dam not just forcing air over the car but also through the front bumper opening.
If any of you guys with hood vents could log coolant temps a few laps at some track, then cover the vent with a cardboard inside or similar and log a few more laps, then that would be super awesome.
Yeah, I have been thinking about doing something similar. I have an alumimum under cover now, so it would be fairly easy to make some kind of quick mount for a splitter to use on track only.
My car already have all these air outlets, but I did not see any major differences before/after. A splitter might make them work better by moving some of the pressure up in front of the coolers.
Yeah, I have been thinking about doing something similar. I have an alumimum under cover now, so it would be fairly easy to make some kind of quick mount for a splitter to use on track only.
My car already have all these air outlets, but I did not see any major differences before/after. A splitter might make them work better by moving some of the pressure up in front of the coolers.
If anyone is interested in an aux radiator kit based on what I ended up with, I have created a feeler here in order to try and give back to the community. I got the idea to make a kit when people started asking about the aluminum radiator fittings I installed when the plastic ones cracked.
The short story here is that although Im not Chinese, my car and I are based in China, and I have learned to speak and write Chinese. From when I first started out, I sourced everything myself locally, and gained alot of experience in the progress... fortunately low cost of labor and good access to (hot and humid) tracks enabled me to keep pushing forward over the past year. It has been a super fun process, and at one point I had 8 coolers and three additional pumps on my car. I even installed sensors to check if the N54 water pump was a bottleneck.
Now although most of my ideas didn't work, and I ended up with a setup that is really just BMW M+, I am not aware of any other cost-effective aftermarket kits that offers something similar to get you started.
If anyone is interested, then deadline is Nov 1, due to my latest travel plans.
The short story here is that although Im not Chinese, my car and I are based in China, and I have learned to speak and write Chinese. From when I first started out, I sourced everything myself locally, and gained alot of experience in the progress... fortunately low cost of labor and good access to (hot and humid) tracks enabled me to keep pushing forward over the past year. It has been a super fun process, and at one point I had 8 coolers and three additional pumps on my car. I even installed sensors to check if the N54 water pump was a bottleneck.
Now although most of my ideas didn't work, and I ended up with a setup that is really just BMW M+, I am not aware of any other cost-effective aftermarket kits that offers something similar to get you started.
If anyone is interested, then deadline is Nov 1, due to my latest travel plans.
Interested, but my current plans are to add an oil cooler (cooler-less from factory) in front of the passenger wheel and a trans cooler in the location it looks like you're using. The attraction of this is that it might alleviate the cold-weather issues the CSF has. It's unclear to me if those are only with the AT rad or with the MT as well though--considering just upgrading to an MT rad and just having the AT cooling live independently, particularly since I'm probably not dedicated to do the relocations your kit seems to require.
Is the cold-weather issue you mention that the CSF might leak coolant?
I do not know about other transmissions, but for the DCT, the AT radiator is also used to heat up the DCT after cold starts.
