So I have been changing my oil with Motul 5w-40 x-cess 8100. Reason why is because all the local PCAR Cayman racers are using it.

I have read that I should use an oil with a 80,000 psi or better and a high ZDDP rating. And I have not found any technical specifications listing Motul 8100.

Anything better or stick with it?

JC,

You have not indicated the way you use your boxster. The prescription for a daily driver and a track car are black and white, oil and water. One needs a low viscosity oils with lots of additives (detergents, acid neutralizers) the other needs exactly the opposite.

You also did not specify your car, year, motor.

Finally, i have no idea what the 80,000 psi is - maybe a film strength on some test, but its not a normally printed specification.

The best compromise is really very simple: Any A40 certified oil. They will all be 0w40 or 5w40 with ACEA A3/B4 and lots of additives. Not ideal for track, but OK in typical new engines, and great for all other uses.

brand is less important than one would be led to believe - there are only a handful of base oil makers and additive makers. The blend matters, yes, but.....

As to ZDDP - for old flat tappets, yes. For racing or break-in oil, yes. For street? Meh. I do regular oil analysis at a lab and can confirm that the major brands, under normal use, hold up perfectly well and do a terrific job. Pay more attention to: changing it sufficiently often that acids and water do not accumulate as they will. This is also reduced by continued operation about 212 degrees F - like 20-20 minutes after complete warm up - and all that stuff boils off. The absolute worst situation for oil is to start a car up 3 times a week and drive it 10 minutes to the golf course (or whatever) and 10 minutes back. By the way, this wort of driving probably benefits from a 0w20 with huge additives - death if ever run at WOT and hgih revs..... the inherent trade off.

So, go to Wally World, buy whichever well respected brand of 0w40 / Porsche A40 is on sale, and move along. Truly.

G

Grant

gee-lenahan-at-gee-mail-dot-com

Grant nailed it . . . . . buy oil meeting the Porsche A40 spec when on sale, change it often (oil is cheap insurance), always drive till the car is hot. It really is that simple.

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JC Costarakis
So I have been changing my oil with Motul 5w-40 x-cess 8100. Reason why is because all the local PCAR Cayman racers are using it.

I have read that I should use an oil with a 80,000 psi or better and a high ZDDP rating. And I have not found any technical specifications listing Motul 8100.

Anything better or stick with it?

You are smart to seek out tech specs on an oil before using it.

The oil is Porsche approved, has the A40 tag which all approved oils carry.

Here's a link to the info I could find on the oil:

[s3-eu-west-1.amazonaws.com]

Its HTHS number is just a smidge less than Moibil 1 0w-40. (Kind of funny the racers missed that.) Here's a link to some info on Mobil 1 0w-40 oil:

[www.mobil.com]

If you want the highest HTHS numbers Mobi 1 5w-50 (not a typo for 15w-50!) needs to be considered. A link to its data sheet is below. Beware Porsche calls for 0w-40 if one uses the car in cold weather, defined by a low temperature of -25C.

[www.mobil.com]

Because the Motul oil is approved and assuming it doesn't get cold enough where you live and drive to require 0w-40 oil I think you are ok with using Motul 5w-40 X-Cess 8100 oil. Don't run the oil too long. 5K miles seems to be the "limit" based on my seat of the pants estimate. I note in both of my cars engine noise both at cold start and at other times increases as the oil gets close to the 5K mile mark. (This is true with 0w-40 oil or 5w-50 oil.) And brief smoking at cold start is more likely to occur. My usage is pretty consistent day in and day out and season in and season out.

I thought the reason to use a 0W instead of 5W is because most of the wear on an engine occurs when you start it up from cold and 0W provides better protection in cold.

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boxsterd
I thought the reason to use a 0W instead of 5W is because most of the wear on an engine occurs when you start it up from cold and 0W provides better protection in cold.

If you're parking the car outside and starting the car in sub-freezing temps I think that makes sense. Having said that, we store the car in the winter and I doubt it's ever been started in temps below 40F.

As to 0w40 HTHS - they are all marginal - its very tough to achieve A3/B4 and 0W at the same time. I told the story long ago of one (un named) manufacturer watching another try....
People love to find boutique oils ( and everything else) that they think is magic, but as i stated above, there are only a few base oil producers and a few additive producers, and the rest are blenders. Or both.

My head-oil temperature never gets above about 240F on the track and 220F on the street. Highway or steady state backroads street is more like 190-200. Interestingly, its highest on the street during stop and go (typically not high rmps nor pressure). So the idea of peak temps and heavy loads is a unicorn on the street. Of course, "spot" temps int he bearings and cylinders are higher no doubt, maybe a lot. Wish i had data, but few mortals do.

Back to 5w50 vs 15w50: But over time any (well any that we can afford) oil with a wide viscosity range shears down more quickly. One of the additive formulators from the Exxonmobil lab specifically called that out, for track use.
He also noted the obvious, 15w50 is not ideal for a street driven car.

But who needs a 4.4 HTHS for street driving? All the 0W40s are (which are also A40) are more than sufficient for how we use the cars under any quasi-legal street scenario.

If you track the car put the truly tough stuff in for track and then replace with 0w40 for winter.

Grant

gee-lenahan-at-gee-mail-dot-com

The Indy that I've been using swears by either, both are A40 approved and have good reviews on the oil forums.

The engine uses very little oil between changes--usually at 5K--and doesn't smoke at startup.