Mobil1-15-50 and oil pressure
05-29-2004, 05:39 AM
#16
Burning Brakes
Wow, us guys really love talking about oil pressure ! I also use only Mobil 1 15-50 and it runs great, oil pressure never lower than 3 bar and 4.5+ off-idle. Unfortunately, I'm burning about 1 quart per 1000 miles when I drive her hard.
Data point on oil temps - the oil temp gauge I added shows a hair over 180 degrees on the highway and between 210 and 220 in stop and go city driving - ambient temps are 70-80 degrees.
But who really cares... ;-)
Data point on oil temps - the oil temp gauge I added shows a hair over 180 degrees on the highway and between 210 and 220 in stop and go city driving - ambient temps are 70-80 degrees.
But who really cares... ;-)
05-29-2004, 01:19 PM
#18
Instructor
2Tight,
I have an 89 951 and use the same Mobile 15/50. I have the same thing on my gauge as well. When I asked at local Porsche dealer about it, they told me that the gauge actually measures the pressure in one of the oil lines, and not necessarily in the crankcase itself per se. The rule of thumb from what I've read in Excellence is 1 bar of pressure per 1000 rpm's, after the car is warm. My oil pressure actually drops to 2 bar at idle on hot days, or if I've participated at a DEW and pushed it hard. I've even had the pressure down to 1 bar a few times, until I've blipped the gas and started rolling again.
I wouldn't worry at all. I find that Mobil doesn't stay neary as thick at operating temperatures as I would like. Aggip makes a full synthetic oil at 20w60 (!!) which I've used, and it did manage to keep my pressure up at the levels you're experiencing.
As long as your car doesn't overheat, you won't bust a seal or anything. The #2 bearing wearing away is endemic to our cars, and no matter which oil you use, it won't prevent this from happening if it has to happen at all.
As for your kid's college, ever considering sending him/her up here to Canada? It's only $2 K per semester (yup...our tax dollars hard at work).
I have an 89 951 and use the same Mobile 15/50. I have the same thing on my gauge as well. When I asked at local Porsche dealer about it, they told me that the gauge actually measures the pressure in one of the oil lines, and not necessarily in the crankcase itself per se. The rule of thumb from what I've read in Excellence is 1 bar of pressure per 1000 rpm's, after the car is warm. My oil pressure actually drops to 2 bar at idle on hot days, or if I've participated at a DEW and pushed it hard. I've even had the pressure down to 1 bar a few times, until I've blipped the gas and started rolling again.
I wouldn't worry at all. I find that Mobil doesn't stay neary as thick at operating temperatures as I would like. Aggip makes a full synthetic oil at 20w60 (!!) which I've used, and it did manage to keep my pressure up at the levels you're experiencing.
As long as your car doesn't overheat, you won't bust a seal or anything. The #2 bearing wearing away is endemic to our cars, and no matter which oil you use, it won't prevent this from happening if it has to happen at all.
As for your kid's college, ever considering sending him/her up here to Canada? It's only $2 K per semester (yup...our tax dollars hard at work).
05-29-2004, 02:24 PM
#19
Nerd Herder
Rennlist Member
Rennlist Member
Mobil1 5W this summer- I noticed the oil press was lower than switched from 15W Mobil 1 that I ran from spring/winter. Test results taken after 30 miles at 75 mph, then stopped at my exit. It was about 2.5 bar vs the 3.0 bar I used to get. It's all about viscosity.
- Keep in mind, I do 5 oilchanges a year.
- Keep in mind, I do 5 oilchanges a year.
05-29-2004, 03:30 PM
#21
Race Car
Hehehe, with Mobil 1 5W30 mine was about 0.5bar at a warm idle. Ran that through the winters, since we hit -40 a few times. Thin oil really helps at start-up.
Anyhoo, I run Amsoil 20W50, and I see 3+bar at warm idle, and 4.5-5.0 bar when it's above 1500RPM.
Those numbers are perfectly normal for Mobil 1 15W40/15W50 as well.
The way I had it explained to me is as follows:
These engines are designed for track use. Even driving hard on the street will not get the oil nearly as hot as driving right up by red-line, full throttle for hours. Our engines are designed to run with good oil pressure even after a track event, so it will definately sit a little high when it is not getting driven too hard. Nothing to worry about.
From what I have heard, the only real worry about high oil pressure is blowing out a seal. If that's what you're worried about, remember, the oil pressure is measured inside the oil cooler housing, right by the oil filter. Everything that is under that much pressure is designed to take it. That is not crank-case pressure, if it was, you would definately see oil blowing by both front and rear crankshaft seals =)
Anyhoo, I run Amsoil 20W50, and I see 3+bar at warm idle, and 4.5-5.0 bar when it's above 1500RPM.
Those numbers are perfectly normal for Mobil 1 15W40/15W50 as well.
The way I had it explained to me is as follows:
These engines are designed for track use. Even driving hard on the street will not get the oil nearly as hot as driving right up by red-line, full throttle for hours. Our engines are designed to run with good oil pressure even after a track event, so it will definately sit a little high when it is not getting driven too hard. Nothing to worry about.
From what I have heard, the only real worry about high oil pressure is blowing out a seal. If that's what you're worried about, remember, the oil pressure is measured inside the oil cooler housing, right by the oil filter. Everything that is under that much pressure is designed to take it. That is not crank-case pressure, if it was, you would definately see oil blowing by both front and rear crankshaft seals =)
