David,
That's what I basically did this weekend too. Adjusted my throttle (Huge dif) put a Steve Wong chip in (huger dif) and cleaned stuff under the car that probably never thought anyone would ever clean.

 

Hi,
engine lubricants that are Approved for use in our cars (synthetics) operate best in a range around 90-120C. They are very stable way beyond that figure and of course "local hot spots" such as the turbo's oil return line can reach 140-150C in normal use
A "core" lubricant temperature range of around 92-105C is almost perfect.

Approved synthetic engine lubricants operate at a temperature about 10% less than a mineral oil with a similar viscosity. Most mineral oils tend to oxidise quite rapidly above about 110C according to formulation etc.

Engine lubricants suffer a lot in use from operating too cold (most Anti Wear (AW) components operate above 50-55C) and of course are quite viscous (measured against their 100C rating) until they reach 90C plus
Mobil 1 0w-40 at 80C has a viscosity equivalent to a SAE60 lubricant at 100C!
A typical 20w-50 Mineral oil at 80C will have a viscosity of about 34cSt, only a little less viscous than Mobil 1 0w-40 is at 60C

Engine lubricants that are quite viscous (say a non Approved mineral 20w-50) tend to be slow movers in critical areas within an engine. As an example some may take up to nearly 5 minutes to enter and clear a piston's ring pack

So, in summary, getting the oil up to around 80C quickly is very important and then keeping it in the "ideal" operating range is the aim of most engine design Engineers

I hope that this is of some interest

Regards

 

Doug: Your paragraph #5 - is exactly why Porsche has always stated to not use a garage warm-up. Get in your car, start it and go! Even my '06 F 150 manual states that cold morning warm-up is not necessary (my neighbor lets his truck idle for at least 10 minutes before he leaves for work!); you're absoutely right, the engineers want that oil to warm up quickly. Also, regarding warm-up following a cold start, the Tiptronic S transmission fitted to '05 and later 911s (997s) has a program that prevents early upshifts, all to allow the catalytic converters and engine to come up to temp more quickly.
Pete

 

^^ Interesting !

does this mean i can 7000rpm straight out of the garage?

 

Hi,
Pete - you are correct. It is wise to let the engine "stabilise" for only about 10sec (checking for OP, charge and etc) and then limit the engine's revs as you drive the vehicle up to what is a "normal" operating temperature. In water cooled engines the oil's temperature trails the coolant's temp. by around 20C in the early stages (dependant on the lubrication system's design etc) of a cold start. A 928 S4 for instance can take up to 30 minutes to reach its normal "core" temperature depending on startup ambient and etc

As many Porsche engines normally operate with an oil temperature around 95C the following are some other examples of viscosity at that temperature;

1 - Mobil 1 0w-40 (Porsche Approved) has a 15.9cSt viscosity nearing that of an SAE50 lubricant at 100C (a range 16.3cSt - 21.9cSt)
2 - Mobil 1 5w-50 (Porsche Approved) has a viscosity of 19.6cSt

Other lubricants - but not the subject of the title of this Thread follow;
3 - Mobil 1 5w-40 "Turbo" Diesel has the viscosity (16.6cSt) of an SAE50 oil at 100C (16.3cST)
4 - Mobil 1 15w-50 EP has a viscosity of 20.3cSt
5 - A typical 20w-50 mineral oil will have a viscosity of around 22cSt which is the same as a SAE60 oil at 100C

Regards

 

Pavegeno928, I also have an 88 Carrera. In extremely cold weather, my car heats up to about 176F. It can get up to 235F in extreme summer heat with the AC off, but never above that number.

The best 911 engine temperature chart that I've found is from Bruce Anderson:

Oil Temperature Meaning
180-220 F Normal operating temperature
230 F Warm
240 F Hot
250 F Too Damn Hot

 

Murph,

That sounds like what I see. It's been in the 40s-50s here in FLA the past week or so and the temp has gotten up to 194F (first narrow mark) when I run the car hard. The oil cooler lines in the right front wheel well have yet to feel warm at all. I need to service my ac with some freon and run the compressor to get the oil temp hotter to see if the oil is getting to the front cooler. If the oil isn't bypassing to the front cooler, that could be why my temp gets up to the 120C(248F) mark in stop and go summer driving with the ac on. Thanks for the input.

Geno

 

Pavegeno928,

Spider911 has an 88 Carrera and he installed a different thermostat for the external oil cooler fan. The Porsche fan comes on at 244F, but that is too hot IMO. Check out this thread: https://rennlist.com/forums/showthre...bmw+fan+cooler

 

Actually, the front cooler fan should turn on at 220 F. If it doesn't the fan switch/thermoswitch is probably bad. Of course, if the thermostat for the front cooler isn't opening the fan can't help anyway. The front cooler should be hot to the touch at 195 F.
Pete

 

Here is an update...got the car warmed up and then got the temp above the 90C/194F mark with the AC running. Right at that point the RR wheel well thermostat opened and I could feel the warm oil making its way to the front cooler. However, after a good 5-8 minutes with the temp up to 100C/212F (9'oclock position), the warm oil hadn't made it to the right front oil cooler. The warm oil was about up to the right front fender.

I guess I was thinking that once the thermostat opened, the oil would flow fairly quickly to the front oil cooler and back. Does this sound normal or does it sound like I have some type of restriction in the lines or the cooler?

Thanks to all for helping me with my learning curve.

 

It sounds like your thermostat isn't opening all the way.

 

Hi,
typically, oil thermostats have a "crack" or opening point and may be fully opened up to 10C later. It is not uncommon for the thermostat to "cycle" depending on the ambient, use and airflow
Some heat losses are also likely occur on the way to and from the cooler depending on the location, when they are remotely mounted

As synthetic oils also have much better flow characteristics than mineral oils the temperature differences within the lubrication system can vary by as much as 10C and perhaps even more

Regards


Regards

 

Peter, for the 911 Carrera, the Bentley manual indicates that the external oil cooler fan comes on a 244F. Pelican sells a stock replacement 110C thermoswitch for the fan which "comes on around 240F". Where is this 220F coming from?

 

Yikes! Boy did I ever goof. 244 degrees F it is, with a 118 degree C switch, 230 degrees F with a 110 degree C switch. I have been under the impression, for a very long time, that the coolers were fitted with what I now know to be BMW # 61 31 13 64 273, which requires a different connector on the wire, that turns the fan on at a lower temp. No wonder I never had a customer tell me that his fan used to work, but doesn't any longer, they never turn on in L.A.! When I bought my PCA car it was already fitted with a Carrera cooler and fan, and we wired the fan to a dash switch (after we tested the fan and found that it turned on at about 220 degrees F), and we set up a number of cars the same way, not bothering to use the temp switch. Sheeeesh!
Pete

 

The BMW switch is a 91C/195F switch -- although I've also seen it listed as a 99C/210F; maybe BMW makes different models?. Here's the BMW one (left) and the factory one on the right. Like Pete points out, the BMW has a different wiring arrangement (I think Porsche uses the cooler as a ground), but it can be adapted. A lot of people wire in a dash switch at the same time.



Auxiliary Fan Switch 2-Prong (White Top) 91 Degrees

Part # is: 61-31-1-364-272-91-M36

and cost was $13.75 from our host,