67King

It is the most expensive oil out there to manufacture, to the best of my knowledge. Absolutely top shelf base stocks (the only one with 3 different ester base stocks, most use only one, Motul 300V uses two). But the NT additive is very expensive.

That said, most users realize a significantly longer drain interval than most other race oils. Karl Poeltl (Racer's Edge) did a case study on it with is World Challenge 911 a few years ago. 5 weekends, 9 races, 1700 race miles with a single fill, and the oil was still good at the end of the year. That is a single fill, rather than 5. So even though it is more expensive than many other oils out there, it is more cost effective for most racers.

blade7, Motul 300V is another very good race oil. Its retail price here in the States is on par with Millers, but it is often discounted.

Thom

I'm in the €zone and buy mine online here, from the UK. Takes about a week to receive it.
It does not turn out a lot more expensive than the Motul 300V that can usually be found locally.

H.F.B.

Thanks for the link

Thom

Bitte sehr.

Perhaps this will be obvious to most but when changing to another type of oil it is probably worth it to drain the oil cooler so that the remains of the old oil does not mix too much with the new one when the oil thermostat opens. The new oil keeps its fresh light colour for longer too...

Thom

Double post, sorry.

RajDatta

Just switched to this on my air-cooled C4S. So far so good. Will be trying it on the turbo soon.

blade7

Thanks, I'm in the UK but I'll check the Motul price before the next change. I change the CFS every 3k miles, maybe I could run it longer as none of that is in traffic or short journeys.

JET951

Forgot to mention , we see lots of worn to badly ( but not worn out ) no 2 con rod bearings ( big end bearings ) on 944 , 944S, 944S , 951 , 968 etc when we remove the sump to replace an old leaking sump gasket & we always remove No 2 con rod cap to have a look at the No 2 con rod bearings ( big end ) & if the said 944 ( any version ) had at times in the past engine oils that were just a bit too low on Viscosity( for the given ambient temps ) & naturally being a sporting type of car the owners will from time to time give the engine near full power , even if its just overtaking on the road etc

WE discover worn No 2 bearings doing an old sump gasket multiple times every year, meaning not the same car but multiple 944 variants & naturally we install new con rod bearings in situ

The scariest ones are the first time track Porsche owners , be it 944 , 944S , 944S2 , 951 , 968 that we are preparing to do a novice track set up , meaning making sure that the cambelt etc is OK or replaced , all new oils , better brake pads & maybe hoses ( basic stuff like that ) & luckily in the case of a 968 we had here mid year ( doing the first basic set up ) we got the OK to remove the sump to rectify a badly leaking sump gasket , we checked no 2 & its was one of the worst worn conrod bearings we have seen on a 968 that has spent its entire life as a road car ( great catch ) & with new standard bearings all was well & with 25w-60 oil she has gone out to the track multiple time with no issues

And yes we discovered ( no surprise to me at all ) that this poor old 968 had been on a so called fully 5w-40 synthetic for a few years and its just did commuting in traffic type of work ( the new owner had previous service receipts showing the oil used

The reason I mentioned this is because if an old 944, 944S ,944S2 ,951 ,968 goes to the track with worn con rod bearings , then the highest viscosity racing oil will not save this engine at high RPM , it will go BANG

The other thing worth knowing is , Never Ever make a more track orientated 944,944S , 944S2 , 951 , 968 engine ( meaning an engine that is being assembled on an engine stand ) with old con rods , always use new good quality after market rods ( there is only 4 of them and they are not expensive ) and will pay you back with reliability = big saving in money as compared to a rod letting go ( and they do ) , because when they let go it destroys everything

Smudo

Is it recommendable to use racing oils like Motul 300V on 951 that is usually used on street and only occasionally sees the track? Are there any disadvantages for using the racing oils on street car?

67King

You have to know about the oil. Some race oils are fine for hte street, more of them are not. 300V is one, unless they have changed their formula recently. Millers is definitely one that is fine to run on the street.

Others that have very light detergent packages, or insanely high VI, will not last but a few hundred miles. The Millers will last several thousand miles with no issues. Friend of mine just had an oil analysis done on his car, 3000 street miles with 10 track days (he is an instructor, as well) intermixed. Report was stellar. Some race oils would probably have caused a failure with that much use without a change. One of the high up guys at Millers could go 20,000 miles on his daily driver (diesel Jag) on the race oil.....but he was doing regular oil analyses on the oil.

pole position

For street use M1 20-50 V Twin is all you ever need and readily available at Wal Mart off the shelf.

Smudo

Thanks. I understood that Motul 300V is not suitable for longer intervals. I am using Bred Penn 20w50 but plan to change to synthetic oil for next season. I understand that Millers CFS 10w50 NT might be good choice but is costs also quite much. I manage during a season (spring to autumn) around 2000 - 3000 miles with couple of track day events and would like to change the oil once in a season. The engine as of now is standard but I plan to increase the boost to around 1 bar. Would Millers Classic Sport 20w-50 Semi Synthetic still be a good choice?

67King

If you track the car, the fully synthetic CFS would be the best bet. You could probably extend it for two years, actually, but I'd do an oil analysis before putting the car away for the winter. There is a Classic High Performance 15w50 that would be a better street oil choice than the semi synthetic.

Where are you located? I'm inclined to assume pretty far north?

Smudo

I am from Europe and we have here snow and ice during the winter, but I don't drive the 951 from December till beginning of April. I looked today at Millers website and as you said they don't offer 15w50 oil anymore. It's replaced by CLASSIC HIGH PERFORMANCE 20w50 NT. Based on the description seems to be what I'm looking for. Are there any considerable benefits of the 10w50 racing oil taking into account my needs?

Thanks for sharing the information. There are a lot of opinions about the oils for our cars (or any cars) and every new piece of information is valuable for creating some understanding and own opinion.

67King

I would use the CFS 10w50 NT, personally. There aren't really any drawbacks, except for price, and the Classic NT is more expensive, at least over here. The 10w50 will flow a little better at startup.