Cooling setpoints for track use (in celcius)

Asbjorn

Lieutenant
Mar 10, 2018
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European, based in China
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Z4 N54 DCT
Since I am now done with the hardware part of track-prepping the cooling system of the Zed, I would like to quickly touch on the software side. I have done some testing with MHD sport and track cooling, and while they definitely work, I do not like them for several reasons. Here are some of the considerations I have.

  1. My car lives in a climate where the ambient temperature sits at 32-34C for more than 6 months of a year. If I use the sport mode in MHD, there would be long periods of time where the car would never enter normal mode.
  2. I want the car to be able to enter normal mode during all months of the year. This to allow the oil temperature to sit at 110-120C, burn off moisture and achieve better mpg.
  3. On the other hand, when I go WOT and the car detects "sporty" driving, I immediately want coolant to target lower temps in order to build head-room. In this log, which starts as I exit the pit lane and enter a track, the coolant goes from 104C (target for normal mode), to as low as 92C as the DME has entered one of the sport modes already during the warm up lap. It seems that it initially targeted around 95C-100C as I start driving faster (high mode maybe?), and then pulls the target further down after the first WOT event (high + kft mode probably). Later in the log, as I start to request more power, the performance of the hardware is exceeded, and the coolant sits between 100-106C although the target is much lower. This part we can do nothing about in the software.
  4. I would like the car to enter limp mode earlier than stock. My thinking is that this will protect the engine better, and I will get a visual warning that I will notice in the heat of track driving if something is wrong. Also for most of the competitions I do (time attack), it wont make sense to push the car at high coolant temps, as the power will have been reduced anyway. Only problem with this idea is that sometimes you may want to push through, if for instance the coolant got too high only 300m from the finish line.
  5. I don't want to flash the car each time I go to a track. I want to set things up properly once, then test that everything is working correctly - then forget. The list of things I need to prepare for each track session is already way too long.

So here are the changes that I might try, please let me know what you think:

new-cooling-targets.jpg
 
Last edited:

doublespaces

Administrator
Oct 18, 2016
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2009 E93 335i
I'm a little disappointed this died, what did you find out, I assume this continued in another thread?
 

Asbjorn

Lieutenant
Mar 10, 2018
854
602
0
European, based in China
Ride
Z4 N54 DCT
I ended up just asking my tuner to copy over the values from that screenshot to my ron95 street/endurance map. Been using it on the street. So far no problems.

The reason I am running these values on the street is because I want to get a yellow warning earlier in case my water pump fails. For track use the benefit is simply some extra peace of mind.

The only scenario where I might not want those lowered limits is for one lap time attack. When the weather gets really hot and humid in China, coolant might get close to or exceed 111C briefly just before the finish line. I would allow that as it is only one lap and intentional. I have my higher boost ron98 map for that. Also, for such events, my AIM device would be plugged in, showing water temps and predicitive lap time, telling me clearly if what I am doing on a that lap is actually worth finishing haha.