Tier1Terrier

I have a 991.2 C2S. After a brief spirited drive in Normal mode, I got on the highway and reached a cruising speed of 79 in 7th gear. I noticed the oil temp seemed to be a little higher than normal (232) so I decided to see how much the temperature would go down when switching to Sport mode. Since I knew I would be cruising at this speed for about an hour, I thought it would be good to see how low it would go, then turn it back to Normal mode and see it go back up. On the second go around, it never got back up to 232, just 228. In any event, that’s a nearly 30 degree difference in modes at cruising speed. Thought that was interesting because I was expecting only about a 10 degree difference.

pictures may not have loaded in order but you can see the time on the clock.

LexVan

Normal.

You'll get better MPGs at the higher temperatures.

Catharpin

Seems normal based on what I have experienced.

barncobob

normal, mine goes from 226 down to 198 and stays there..heard oil needs to be 212 to burn off water, dont hit sport till around 225

the_buch

I know which mode is better for smiles, but which one is better for the car. Is the higher MPG achieved in Normal due to lower friction because of the higher oil temperatures (which would be good?) or better combustion efficiency (also good but at the expense of sub-optimal lubrication?)? Why the extra cooling in Sport - just a buffer in case you want to pound on it or ??? What are those crazy Germans up to

spdracerut

Higher oil and coolant temps will improve fuel economy. Higher oil temp, lower oil viscosity, less energy loss in shearing the oil. The warmer the parts of the engine, mostly the cylinder walls and pistons and valves, the more heat is kept in the combustion instead of sucking the heat into the metal bits, leading to more efficiency. When you're just cruising on the highway, that's maybe like 50hp. When you're pounding on it, that's the full hp, so magnitudes more heat to reject.

Jack F

Nothing unusual. Drive it and enjoy it in thr mode that makes the most sense for you. Let the car get up to temp before stomping on the gas.

Tier1Terrier

yes I typically idle for about 5 minutes before driving. Gets into the high 1 hundreds and I get Going.

bkrantz

Interesting that water temp stays constant.

spdracerut

The dash coolant temp is more of a dummy gauge. I don't remember the number exactly, but it reads 194 on the dash up to a real value of 220f or so.

LexVan

OK, please STOP doing this. Start the car, put on your seat belt, make any adjustments and go. If you want, you can wait the 60-90 seconds for the car to come off the high idle and settle into the 825-850 rpm range and go. Keep below 4,000 rpm till the oil hits the 180 range. Idling 5 minutes is awful for your car.

Tier1Terrier

@LexVan

Thanks, LexVan. Can you please explain to me the harmful effects of letting your car idle up to normal operating temperature before driving? I don’t understand and am curious. Thanks!

LexVan

Fuel dilution is a big one.
Bad for the environment, comes to mind.
Bore scoring is real. See the 997 Forum.
And completely unnecessary. The car warms up fast already, especially with the appropriate load exerted. You want things coming up to temp in harmony, including the tranny.

LexVan

You live in Florida, Tier1.....put on your big-boy pants! That's not cold.

desmotesta

yes very normal and a lesson I learned the same way you (OP) just did. I drove the car to charleston with the wife for Valentines day , cruising temps at 80-85 MPH were 228-234..

on the way back, used sport mode all the way and temps were between 192-203 ( confirmed via icarsoft) although dash displayed a "fake 194" the whole way back.