How much power would it consume? Are we talking fractions of 1hp or more?

Anyway, I don't care - if it smells like the old castrol R then I'm switching!

 

Hi,
Christer,
Porsche have never recommended SAE60 lubricants for normal use to my knowledge.

Castrol recommend "RS" 10w-60 for "track days" for a wide range of vehicles including yours.
One reason is its ability to handle some fuel dilution in these circumstances and of course its extra high temp. viscosity may maintain oil pressure a little better (at the expense of flow perhaps)

It may reduce oil consumption a little in some engines too - and/or even minimise a few leaks as well
It may also be desirable in very hot climates - 50C+ in some cases but Porsche's highest viscosity recommended, SAE50, is quite a viscous oil - especially for a modern synthetic.

A good indication of the oil's operating environment is the oil temperature gauge - a modern synthetic will tolerate long periods at up to 120C for long periods if the viscosity is as recommeded. Some mineral oils tend to oxidise quite quickly when running above 110C for long periods

5w/15w-50 synthetic oils seem to a fairly universal/International choice for Porsche owners - perhaps its just a good sales pitch from Mobil! I doubt it!!

Johnny G - stick with a FS as the benefits are often unseen! One is engine cleanliness especially in the area of oil pump screen varnish build up etc, better flow characteristics and the better heat removal provided by oils that run up to 10C cooler than their mineral equivalents

This link may be of interest;

http://www.landsharkoz.com/techtips.htm

Check under "Lubricants for the 928"

Regards
Doug

 

Rob, If you will pardon the expression - you can sniff my rear next time we meet....

 

Hi Robmug,
sorry, the lovely "R" castor smell in (now) RS 10w-60 was left BEHIND about 1983
I believe some of the FUCHS range have that aroma now

Regards
Doug

 

Surely there could be some additive that Rob could use? Let's not give up so easily...

 

Doug - that's a shame.

I was following an E30 M3 a few weeks ago and he was clearly driving hard and I could smell Castrol R...wonder what he was running...

 

I doubt if the oil pressure pump consumes significantly more power when pumping thicker oil. That is because at engine speeds much above idle, the oil pressure is controlled by the bypass valve. There is more oil going to the bypass if the oil is too thick. More oil goes where you need it with the correct viscosity.

The scavenging pump moves the oil from the sump back to the tank. It does take more power to pump thicker oil, and more heat is generated in the process. Here, too thick oil is definitely a waste of energy and a source of extra heat.

Your oil cooler is more efficient with thinner oil. A boundary layer between the flowing oil and the metal heat exchanger is a barrier to efficient heat transfer. The boundary layer is thicker with thicker oil. There is less oil flow in the cooler if the oil is thicker. Since the pump pressure is regulated, the thicker oil will not flow as fast in the small oil cooler passages. This means that oil temperature will be higher with thicker oil.

Thicker oil causes higher viscous drag everywhere in the engine - each journal bearing shears an oil film, and the thicker oil requires more energy. The bearings will run hotter with thicker oil for three reasons: 1) it takes more energy to turn the bearing; 2) less oil flows to each bearing if the oil is thick, and; 3) the oil will be hotter bacause the oil cooler is less effective.

I don't know how much extra power we are talking about, but going from a 10W-30 to a 10W-60 I think would cost one or two unnecessary HP. One SAE horsepower is 746 Watts, or about what your stove eye does on medium-high.

I run Mobile 1 10W-30 summer and winter, even in my 200K mile Mercedes beater. I don't have problems with leaks, low oil pressure, or high oil temperature. Fuel economy is pretty good too. Thick oil will help quiet the slapping in an extremely worn engine, but if your engine is in good mechanical condition, it is counter-productive to run a thick oil. Stick with the factory recommendations unless you have unusual circumstances to justify something thicker.

 

As my engine now generates more power=heat, I would also like better protection at higher temperatures (and higher rpm's). Also, this oil is recommended by the people who built my engine and knows its specs...

 

Hmmm,

you might/ might not [delete as applicable] want to read the Pistonheads Porsche forum, a poster on there is making some recommendations as to oils and cars....... anyway, it may be worth a look. Or indeed a question to said poster :-http://www.pistonheads.com/gassing/topic.asp?t=124186&f=48&h=0

Hope this dosen't breach forum rules.

Kevin.

 

Hmmm.....thanks - i have posted to ask him...although to be honest I am going to trust 9M who built the engine rather than some guy on the internet I have never met and know nothing about...

 

Hi Christer,

sorry bout that, It wasn't aimed at you, but a general heads up.......

K.

 

I know...

 

Castrol R, takes me back to my 2 wheeled days....... when I graduated to a four stoke.........I errr wanted that smell back again, I experimented a tad, then I err............put one desert spoon of vegetable oil per gallon of juice in the petrol tank, and hey ho smelly exhaust back again, this time on a four stroke.....

remember though YMMV, and don't hold me responsible if yours goes pop...............


Kevin.