I've been tracking my 135i for about a year now, and living in California means some days are unbearably hot. I've gone to great lengths to keep my N54 cool, and in most >90* a, I can run a full 15-20 minute session without an issue. I've seen a lot of threads and complaints of this mystery problem, and have contributed to some of them as well, but nobody has been able to figure it out or record the event with any significant data, until now (I think?).
First off, I just want to thank Ken @WedgePerformance for absolutely kicking ass in delivering an awesome 91-octane track tune. His response time, enthusiasm and willingness to chat and explain is awesome. Beyond that, Ken made himself available for me when I needed him most: At the track yesterday for Global Time Attack Round 3 at Buttonwillow Raceway. Unfortunately, with 104* ambient temps, my car had about 1 lap or less in it before the dreaded rolling limp mode occurred, but I was finally logging at this moment to record it.
Despite my best efforts on the cooling system, my temps were all too high. The worst of the three (Oil, Water, IAT) was the coolant, seeing a high of 245*. This is a stock turbo car running about 15psi with full bolt ons, including stock location silicone inlets.
Cooling Modifications:
CSF Radiator (BMW coolant / distilled water 50/50 mix with Water Wetter)
VRSF 7.5" Race Intercooler
Custom twin Setrab 19-row oil cooler setup, thermostat removed (Red Line 10w40)
You can see below; with coolant temps above 240*, Tq Lim 512 activates to save the motor, pulling timing and providing a a max of 2-3psi.
Ken and I are going to work on some cooling table adjustments still, but in the meantime, I've got some work cut out if I want this car to handle abuse in high heat. I don't expect to be able to run full sessions on these shitty 100*+ days, but even another 2 laps would have been the difference for me in breaking my personal best time and placing well at the race. On 3 specific clean laps, with predictive lap times that would have put me on the podium, I made it to the last turn getting onto the front straight, went for the throttle and BAM, no power. It was pretty heartbreaking but this is racing and I came home with valuable data to hopefully avoid this happening again.
Next for the car will be a revisit to the radiator. I'll start with 100% distilled water and water wetter. I'll also be adding a center hood vent from Trackspec Motorsports to start getting some more heat out with a ton of added flow above the core. I'm going to replace my two 19-row Setrab Oil Coolers with two larger 25-rows instead. The VRSF intercooler will stay for now, but I do wonder at what point the intercooler density has a negative impact on flow to the radiator... It's all a sliding scale, gain in one area, lose in another. I think some water/meth injection would be a nice addition, too, just for cooling properties, but I'm not into adding extra pumps, fluids and more weight, so that'll be last.
Hope this is helpful to some of you.
-Alex
First off, I just want to thank Ken @WedgePerformance for absolutely kicking ass in delivering an awesome 91-octane track tune. His response time, enthusiasm and willingness to chat and explain is awesome. Beyond that, Ken made himself available for me when I needed him most: At the track yesterday for Global Time Attack Round 3 at Buttonwillow Raceway. Unfortunately, with 104* ambient temps, my car had about 1 lap or less in it before the dreaded rolling limp mode occurred, but I was finally logging at this moment to record it.
Despite my best efforts on the cooling system, my temps were all too high. The worst of the three (Oil, Water, IAT) was the coolant, seeing a high of 245*. This is a stock turbo car running about 15psi with full bolt ons, including stock location silicone inlets.
Cooling Modifications:
CSF Radiator (BMW coolant / distilled water 50/50 mix with Water Wetter)
VRSF 7.5" Race Intercooler
Custom twin Setrab 19-row oil cooler setup, thermostat removed (Red Line 10w40)
You can see below; with coolant temps above 240*, Tq Lim 512 activates to save the motor, pulling timing and providing a a max of 2-3psi.
Ken and I are going to work on some cooling table adjustments still, but in the meantime, I've got some work cut out if I want this car to handle abuse in high heat. I don't expect to be able to run full sessions on these shitty 100*+ days, but even another 2 laps would have been the difference for me in breaking my personal best time and placing well at the race. On 3 specific clean laps, with predictive lap times that would have put me on the podium, I made it to the last turn getting onto the front straight, went for the throttle and BAM, no power. It was pretty heartbreaking but this is racing and I came home with valuable data to hopefully avoid this happening again.
Next for the car will be a revisit to the radiator. I'll start with 100% distilled water and water wetter. I'll also be adding a center hood vent from Trackspec Motorsports to start getting some more heat out with a ton of added flow above the core. I'm going to replace my two 19-row Setrab Oil Coolers with two larger 25-rows instead. The VRSF intercooler will stay for now, but I do wonder at what point the intercooler density has a negative impact on flow to the radiator... It's all a sliding scale, gain in one area, lose in another. I think some water/meth injection would be a nice addition, too, just for cooling properties, but I'm not into adding extra pumps, fluids and more weight, so that'll be last.
Hope this is helpful to some of you.
-Alex
