Things noticed about rain an my car

Just came back from a 260 mile trip from Raleigh, NC, to DC in my '09 997 S. It rained heavily the entire way home yesterday--basically, if you saw hightligths from the Giants game in NJ and the Pats game in MA, that's what I was in. The air temp was essentially the same for the trip down and back. It took four hours down and five back. The car handled very well in the wet. It's been a long time since I've taken a roadtrip in that kind of weather. You could feel the car bog down at times as it hit a sheet of water on the highway. Anyway, I noticed that the oil temp never exceeded 175 degrees. It always seems to stay at 200 on such trips. The water temp, as usual, was straight up 175. So, for some reason no impact there. Could the road spray from the rain have enough impact to cool the engine block and thus oil temp by 25 degrees? The tire pressure was never up by more than 2 psi from its initial cold-start readings. I can get that just by traveling the four miles to work. On roadtrips, it can rise by at least four or five psi. So, the water did impact the tire temps, too.

I've pushed the limits of my Porsches, and luckily have never found it. Since I've been doing that less so as i've crossed over into the second, half century of my life, I opted for the Continental DW (Dry/Wet) the last time my car needed new rubber. My car is a daily driving, workhorse, roadtripping vehicle. Don't get me wrong, I do play--it is a Porsche, afterall--but do so with less frequency. So, thought I didn't need to go with high-performance footwear. The Continental DW gives up some on performance, but you also get more miles out of them, good thing with 19 inch wheels. And, I've yet to hit the performance limit in them, either. After Sunday's ride home, I'm glad I opted for the Contis. I saw a few accidents along the way home (a semi with a blowout about five cars in front of me, one car upside down and several others spun out in the grass and mud). Meanwhile, I was able to keep plugging on home. The undercarriage must be about as clean as the day I purchased it. The rain just never let up. Oh, and love the rain-sensor whipers. I just turned them on and let the computer decide the speed. I was never frustrated by its choice, either. A must for daily drivers.

No question the rain water kept the oil temp down.
The coolant temperature is regulated by the thermostat, so it's always going to be right around the 175F, but the cold water was constantly cooling down the oil pan which has quite a bit of exposed area.
Water is a much better conductor of heat than air.
I see this all the time when I'm at the track in the rain.
Oil temps are usually 35 degrees cooler when running in the rain .
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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