Running 10C cooler in Sport than in Normal
 

I'm wondering why this is and if true why wouldn't I always choose Sport mode to get this benefit from an engine protection viewpoint (though probably give up a bit of mileage)?

Found this to be true too, I always drive in sport mode

Oil temperature, so an accurate difference (as you know the water temperature gauge is fake news).

I didn't know this!!!

FWIW, this is the same thing that occurs on my Spyder as well, so it's not just for the TT/TTS.

It's pretty much all the modern Porsches. 991, 991TT, 981, 95B (Macan)...

If I recall reading this correctly, there are louvers that close off some of the airflow to the front radiators in Normal mode to reduce drag, and that reduced airflow increases the oil temperature. So it's not really the increased temperature that gets better mileage - it's reduced drag. I remember this specifically from my C4S - not sure that the Turbo does this though.

Weird - you'd think Porsche would want to reduce drag in the sportier modes? Plus, how much difference could that bit of drag make at average speeds more typical of running in Normal?

I'm still trying to figure out whether the higher operating temperatures might result in reduced friction to deliver higher fuel mileage and therefore less wear and tear, or if the higher temps result in a combustion efficiency though possibly greater heat-related stress??

Thanks all. For those interested, I found an older thread on the 991 board with some speculations: https://rennlist.com/forums/991/1081...port-mode.html ... I'll try not to duplicate effort :)

Well, knowing how effective an oil fan override switch is on an aircooled car, my guess would be the engine management would simply change the fan on temperature when you select sport mode.

I would think it would be a small effect, but these days manufacturers have to operate within a number of sometimes conflicting regulations (CAFE, emissions, etc) where even small effects make a difference when combined. For what it's worth, this link https://www.porsche.com/usa/models/911/911-carrera-models/drive/active-cowl-flap/ is what I alluded to having read where Porsche says they do this with louvers for drag reduction purposes. While drag reduction is certainly valuable in sportier modes, the engine is more likely to be generating higher output and oil cooling would be more important in sportier modes. In addition to what happens in Sport or Sport+, this is also an "on demand" situation in Normal - based I would suppose on oil temperature.

Thanks - I hadn't seen that info from your link before. The only question I still have is what oil temperature is better for wear and tear on the engine itself - higher oil temp=less friction=lower wear (though probably slightly higher oil consumption) ... or ... lower oil temp=lower heat stress on components? Or, more likely, I'm having heat-stress over nothing material :)

I think it's a range rather than any specific temperature. You want the oil to get hot enough to vaporize any water that has accumulated in the oil which means that at some point in the engine it has reached 212 or higher, and that defines the lower limit. As temperature increases the viscosity decreases and the oil film gets thinner, increasing wear on the engine; the lowest acceptable viscosity for proper lubrication defines the upper limit.

The indicated temperature is where the temperature sensor is which may not necessarily be the hottest point. This link suggests the range is 180-210 and also explains this relationship between oil temperature and engine life.

Thanks for the link and your continued interest in this topic. My earlier link suggested the best range is 230-260 and this has it at 180-210 (i.e., below the magic 212 target to evaporate any moisture). Plus, why would Porsche purposely engineer the car to run at 230 in Normal mode, including if it helps fuel mileage there must be less friction? I'm compelled by your link to ensure I use an oil (thinking Motul 5W40) that retains reasonable viscosity at the 'Normal' operating temperature. Many thanks, Doug