[JD11937]

Why does bmw run the engine so hot though?

I've been using mhd's sport cooling since the day it was released without any issues so far. I know logically bmw wouldn't run the engine at these temps if it was bad for the engine but isn't heat always the enemy? My logic was better to damage a water pump instead of heat doing something worse.

[weehe126]

Running an engine hotter, within reason, is more fuel efficient.

[kern417]

Originally Posted by JD11937

Why does bmw run the engine so hot though?

I've been using mhd's sport cooling since the day it was released without any issues so far. I know logically bmw wouldn't run the engine at these temps if it was bad for the engine but isn't heat always the enemy? My logic was better to damage a water pump instead of heat doing something worse.

Everything has an *optimal* temp, so that means too hot is bad but too cool is bad as well.

[Wires]

Back in the "olden days" engines came with a 195F thermostat to give you better mileage. That is the optimal temperature for the balance of power vs performance. Going hotter made the car more efficient on fuel, but power suffered.

If you wanted more HP, you'd install a colder thermostat (165F), but then you lost fuel efficiency and cabin heat.

Modern EFI does an amazing job of cranking up power, even with temperature due to real time measurements, but colder still gets you more HP due to a denser AFR (more oxygen).

[NISFAN]

BM3 max cooling is only on the intercooler fluid pump. It has nothing to do with engine coolant.

Whether it is worth turning it on or not is a debatable subject. Firstly, when talking heat exchangers cooled by ambient air, there needs to be a big enough delta temperature between cooled medium and cooling medium to make that process work. Secondly, when cruising on the motorway you won't be producing any boost, therefore low IAT anyway. Running the pump in these conditions is only wearing out your pump.
Now in a performance environment, let's say you decide to do a quick single pull out of nowhere. The high boost pressure will heat up the fluid inside the intercooler core, the pump will come on and you will experience a hit of really cool coolant that was previously sitting in the heat exchanger (front rad). Perfect.
What about track work? Well the standard setting will switch the pump on as needed anyway.

So in summary, I don't see any case that would improve performance over the standard 'sensed' setting.

The aircon also uses the same cooling circuit, so probably also triggers coolant pump intermittently.

To the drag racers out there, probably a manual pump and fan on switch would be beneficial whilst waiting for your run.

[chris-c]

I've found when doing 100-200 pulls it takes quite some time for the car to cool off so I run it in max cooling mode and it cools down a fair bit quicker. It also seems to bring the temps down after a lot of heat soak rather quickly.

[weehe126]

Originally Posted by NISFAN

BM3 max cooling is only on the intercooler fluid pump. It has nothing to do with engine coolant.

Whether it is worth turning it on or not is a debatable subject. Firstly, when talking heat exchangers cooled by ambient air, there needs to be a big enough delta temperature between cooled medium and cooling medium to make that process work. Secondly, when cruising on the motorway you won't be producing any boost, therefore low IAT anyway. Running the pump in these conditions is only wearing out your pump.
Now in a performance environment, let's say you decide to do a quick single pull out of nowhere. The high boost pressure will heat up the fluid inside the intercooler core, the pump will come on and you will experience a hit of really cool coolant that was previously sitting in the heat exchanger (front rad). Perfect.
What about track work? Well the standard setting will switch the pump on as needed anyway.

So in summary, I don't see any case that would improve performance over the standard 'sensed' setting.

The aircon also uses the same cooling circuit, so probably also triggers coolant pump intermittently.

To the drag racers out there, probably a manual pump and fan on switch would be beneficial whilst waiting for your run.

I run MHD and it has both an intercooler and engine coolant max cool settings. Would assume BM3 does too.

[G.Newt]

Y'all want more engine cooling? Take off your engine cover lol.

[john_f30]

Originally Posted by G.Newt

Y'all want more engine cooling? Take off your engine cover lol.

Hahaha!!

[Freddie_Rome]

I'm a MG FLasher user and I got "Max Cooling" option, which accelerates IC flow, and "Regular Target Engine Temperature" which keeps oil/coolant temperature all the time down to the set value. I put 99° celsius but you can set down up to 80°