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Most of the recommendations I've read above (and I value these opinions), are Mobil 1 15W-50. But as far as I can see, this is not available in Australia. It is not listed on the Mobil website (Aus version). I dont like the idea of buying 5L ex USA (shipping would be horrendous).
Any Aussie shark owners out there that can confirm this? and if not, what retail outlets have it available.
Because Porsche said so, I give my red-head a "factory fill" of Shell Formula. (actually, whatever oil I find on sale is more than adequate for my punishing use of the old lady - driving around at 60 to 80 km/hr with occasional spurts to 100 km/hr does qualify as punishing use, doesn't it ;-)
Most of the recommendations I've read above (and I value these opinions), are Mobil 1 15W-50. But as far as I can see, this is not available in Australia. It is not listed on the Mobil website (Aus version). I dont like the idea of buying 5L ex USA (shipping would be horrendous).
No need. Get some Motul oil. That's no spelling mistake and I was a bit surprised that it didn't make the list. Then again, Rennlist is North American centric (and that's not a criticism just a reflection of the reality). Anyways, this French company supplies the Land Down Under with 15W50 and other weights. You can also visit http://www.datateck.com.au/Lube/MotulAus/ and check what they recommend for your car.
ok guys, can't remember what oil I last poured and I'm 1500 miles away from my 928, BUT, what would the scientific reason be for using a high viscosity oil in our cars, especially if one drives like an old lady?
I use liqui moly 10w60, before i used royal purple 20w50 but here in Italy is rare to find and costly, always more than 180 us dollars for 8 quarts. Liqui moly seems to be the best 10w60 on italian/european market for its specs and availability, holds pressure from 3 bars on at idle even during this Hot summer (35-38C), it can stand the stress during track days .internal are really clean.it is very like royal purple( but a bit better for pressure and oil consumption). Tried castrol rs 10w60:good performance the first month/400km I put it in the engine, then a big drop in pressure, 2 at idle and not more than 4 at 2500 rpm... plus noisy valve lifters after cold start.never again.
Liqui Moly here as well, break in with lower (hot) viscosity and then when loading it up at higher boost levels switching to higher (hot) viscosity version.
I'm not sure whether breaking in the engine with conventional oil has any scientific basis at this point. It's probably just marketing of special break in oils, old habits, and superstition. Every high end car engine gets broken in with a fully synthetic oil at the factory today. But all the oils are so good nowadays that everything will work, and one should probably put some weight in what the experienced people do, so... plus flushing the engine with cheap oil is cheaper than flushing it with expensive oil!!! ;-)
I also have some "unconventional" theories about oil's hot viscosity. The hot viscosity of an oil doesn't correlate that much with the oil's load protection ability anymore. If the load protection is high, the viscosity shouldn't matter that much to load protection ability, somewhat tautologically.
With the 928 style oil pump, too, there's in my opinion no logical reason to think that lower hot viscosity oil will cause a lower parasitic power loss. The 928 oil pump is positive displacement pump. The oil pressure is controlled by the bypass valve spring, so the pump will always pump against 8 bar (or whatever the spring is set to ask). Suppose we're running rpms at which the bypass bypasses at least some oil. If the flow rate thru the pump is the same and the pressure against which the pump pumps is the same, then power that the pump draws has to be the same as well. Right? (The way modern race engines save power with lower viscosity oil is by simultaneously reducing all clearances thus the flow rate and downsizing the oil pump. That's a bigger project for 928 driver than. Hanging the oil...)
High viscosity does give a higher oil pressure at idle, but what part of the engine needs 8 bars at idle?
So the only thing that hot viscosity changes at above idle rpms is the flow rate of oil that isn't bypassed back to the pump inlet, provided that pump is spinning at a high enough speed to bypass something.
Whether high flow rate or low flow rate is preferred for the 928 is an interesting question...
The short easy answer is 'because the owner's manual says so."
More important than hot viscosity though, is ZDDP level of at least 1000 ppm.
One source argues that there can be too much of a good thing:
In addition, the industry developed a battery of oil tests (called sequences), two of which were valve-train scuffing and wear tests. A higher level of ZDP was good for flat-tappet valve-train scuffing and wear, but it turned out that more was not better. Although break-in scuffing was reduced by using more phosphorus, longer-term wear increased when phosphorus rose above 0.14%. And, at about 0.20% phosphorus, the ZDP started attacking the grain boundaries in the iron, resulting in camshaft spalling.
So more than 1400 ppm in long term use would seem to be counterproductive, according to this source at least.
Generally I use 40 - 50 weight.
On the 0W, 5W, 10W, 15W scale, depends on the weather.
I change oil in Fall and Spring to work with the warmer weather and not so cold winters.
I use the brands listed approved, but I am sure this has changed.
Why do I use this oil? cause of the following.
May be a new sheet out since, but I can not remember when I found this sheet. I found it online, so it could be fake.
Kendall GT-1 20-50. I could go back to Castrol 20-50 if needed.
I switched from Castrol or Royal purple after finding out that both of these have a higher ash content than I'm happy with, although Castrol was and is a fine oil. Kendall comes from predominantly Texas and OK base stocks which are naturally lower in ash, and that is confirmed by looking at the data sheet comparison. Also the hydrocracking of the base oil stock is conducted after they filter and balance the acidity, where in more PA and offshore crudes they add some alkalies to balance the acidity after hydrocracking. It's cheaper to balance the Ph that way, but it doesn't maintain the consistency through the rest of the processing.
I will never use another Mobil product after what they did to the aviation community, and some MB cars.
Mobil 1 15w50. No real brand loyalty at this point. These cars just seem to be well equipped for higher viscosities with the pressure-relief valve rated at 8-9 bar. With a more ordinary car, you might need a lower viscosity so that flow rate doesn't drop off too much at higher RPMs. Also, plenty of ZDDP. Might switch to 5w50 if I start doing more winter driving. But for now, winter is for catching up on deferred maintenance. I'm sure 40 weight would provide better fuel economy, and a tiny bit more performance, but if I really cared about those things I wouldn't be driving a 31 year old car.
01-06-2017 | 06:17 AM
