[manuelbmw]

Hello, yesterday i just find out how to check the coolant temp on my e90 330i and i need to know what's the range, im running 95-98 celsius in town. Is that ok?

[hassmaschine]

it's 90 to ~115c so yeah, you're fine.

[manuelbmw]

Thanks !

[mike3000fl]

it will go up and down depending on driving conditions. The car can control it since the waterpump is electric versus belt driven. It varies pump speed to raise or lower the coolant temp for fuel economy or for performance.

[slimxb8]

201 to 210. Avg is 204 for the most part

[Three_thirty_I]

Well, there are technically 4 temperature maps, but in most cases the engine should be running on Eco mode, so this right.

The four modes are as follows (there is a PDF online that I am referencing here):
• 112°C ECO mode (economy)
• 105°C Normal mode
• 95°C High mode
• 80°C High + mapped thermostat mode

[mike3000fl]

Originally Posted by Three_thirty_I

Well, there are technically 4 temperature maps, but in most cases the engine should be running on Eco mode, so this right.

The four modes are as follows (there is a PDF online that I am referencing here):
• 112°C ECO mode (economy)
• 105°C Normal mode
• 95°C High mode
• 80°C High + mapped thermostat mode

That's good info and I want to thank you for posting it. Is there anyway you can attach or link to that PDF. I love reading that kind of stuff.

[justpete]

Originally Posted by Three_thirty_I

Well, there are technically 4 temperature maps, but in most cases the engine should be running on Eco mode, so this right.

The four modes are as follows (there is a PDF online that I am referencing here):
• 112°C ECO mode (economy)
• 105°C Normal mode
• 95°C High mode
• 80°C High + mapped thermostat mode

What is mapped thermostat mode?

[JDane07]

I was around 170 degrees F driving up to work. Seemed a little low, especially since it's 70 something here in California.

[NEFARIOUS]

Is there any way to program it to actually be lower? When I'm stuck in bumper-to-bumper traffic, it's 105°C and most of that heat radiates into the cabin when I'd prefer to roll the windows down during those times instead of having the air on... But even if it is on it still gets kinda warm, and AFAIK I never had this kind of problem with previous cars.

[hassmaschine]

Probably. I've been looking for those parameters but haven't found them yet.

Keep in mind, your fuel economy will probably drop a bit if you lower it.

[NEFARIOUS]

Low RPM fuel economy isn't really BMW's strong point anyway... Not to mention as long as it isn't as bad as the 4×4 V8 pickup I had I'm good.

[hassmaschine]

I don't think the temp is controlled by rpm, but rather load. The 105c map is probably used for most normal driving conditions.

[Volasko]

Originally Posted by mike3000fl

That's good info and I want to thank you for posting it. Is there anyway you can attach or link to that PDF. I love reading that kind of stuff.

Check this thread out for a link to the N52 tech report.

http://www.e90post.com/forums/showth...=N52+Tech+Info

[justpete]

Originally Posted by hassmaschine

I don't think the temp is controlled by rpm, but rather load. The 105c map is probably used for most normal driving conditions.

Planning to replace the thermostat with a Mishimoto 75C race thermostat with the installation of the new C&R radiator. Hadn't really thought about what that might do to confuse the control of the water pump.

Adding a Setrab oil cooler with a 215F thermostat so I'm thinking it's unlikely to overcool on the street but could be wrong about that. I wonder if I might have to change oil viscosity.

[hassmaschine]

a fixed thermostat? how is that going to work?

wouldn't it make more sense to command the DME to always open it at 75c? actually, that doesn't really make sense either if you still drive on the street. the whole idea of a mapped thermostat is you can have it run cooler when you need performance and hotter when you're just putting around.

[justpete]

Originally Posted by hassmaschine

a fixed thermostat? how is that going to work?

wouldn't it make more sense to command the DME to always open it at 75c? actually, that doesn't really make sense either if you still drive on the street. the whole idea of a mapped thermostat is you can have it run cooler when you need performance and hotter when you're just putting around.

Not entirely sure, honestly. Instructions for the part require the pin to be removed so I'm assuming the thermostat would no longer be controllable. It's only an option at the moment and I suspect it's meant for use in race engines without the stock DME. Thanks for the clarification, I can't find anything online that explains exactly what mapped thermostat actually means.

[Three_thirty_I]

They have tried to reinvent the wheel with this engine.

[justpete]

Originally Posted by hassmaschine

a fixed thermostat? how is that going to work?

wouldn't it make more sense to command the DME to always open it at 75c? actually, that doesn't really make sense either if you still drive on the street. the whole idea of a mapped thermostat is you can have it run cooler when you need performance and hotter when you're just putting around.

Sorry to go on about this but I'm not seeing the point of varying the engine coolant temp other than maybe for emissions. Seems it would shorten engine life.

I can see holding it closed to reach operating temp quickly I suppose but how important is that really?

With a higher capacity radiator would it make any sense at all to have a fixed thermostat at the coolest temp so the water pump runs at its lowest speed most or all of the time and have the engine at the same temp at all times?

Peculiar design.

[hassmaschine]

Engines run more efficiently when they are hot. That includes power. It does help emissions but only because you get more energy out of the same quantity of fuel.

The n52 wasn't designed to run at 75c. I want to try running it hotter, perhaps 90c.

[Three_thirty_I]

The temperature control is very sophisticated on these newer engines, and very efficient. The idea is that it keeps all cylinders evenly cooled and cooled for the best performance or efficiency based on the engine load at the time. I still need to replace the thermostat on my 330i since it seems to be over cooling, and I am pretty sure it is causing performance/economy issues being the way it is at the moment.

[hassmaschine]

I found the 80c and 95c maps. you can actually control it vs outside temp, so you could adjust the map to run it hotter on cool days for better efficiency, and colder on hot days. the default map runs it at a flat temperature no matter what the outside temp is.

right next to it is also the electric fan map.

I've found a couple that look like the 105 and 112 settings but they are single parameters rather than a map. Those are controlled via a threshold (likely load/rpm).