Errsomeone

Agreed. This car would only rarely be driven in cold weather. Your note on the 5W50 is appreciated as it bolsters my question.

As it stands I am still a bit surprised at the temps that P seems to feel are within its normal operating range. Determination as to if I should consider a different oil/weight was one reason I was curious as to the results of this test. I do not think I will get back on track this year, so I will probably just have it swapped before starting next. Either way, will be interested in the result between the six days on the prior sample and the three on the current.

Macster

No. Do not blend the two oils. An oil's additive package is very important and if you mix two different oils they are not the sum of their two parts, but something less.

If ambient temperatures are high enough that one can run 5w-50 year 'round that's fine. I run it in both of my cars here in CA. (Was 101F the other day here and in a couple of days could again get nearly 100F. Stupid "fall" weather.)

But if ambient temperatures get too low -- the temperature Porsche offers is -25C (about -13F0 -- Porsche says to run 0w-40. Frankly to be "safe" I'd switch to 0w-40 at an even higher temperature.

Say if ambient temperatures were at or below 32F that's when I'd run 0w-40. Then when spring arrives and ambient temperatures are above 32F I'd switch back to 5w-50.

4carl

https://mobiloil.com/~/media/amer/us...guide-2016.pdf

Yes. Mobil 1 is fully compatible with conventional motor oils, semi-synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. But the superior performance of Mobil 1 will be reduced by diluting it. (from M! website)

MarcD147

http://www.costco.com/Mobil-1-Advanc...100169676.html

LexVan

I disagree. See post #44 here:

https://rennlist.com/forums/991-gt3-...or-5w50-3.html

And Kevin is; one of the most trusted tunners on Rennlist, has seen hundreds and hundreds of UOA's, and hundreds of these Porsche engines when taken apart.

You can safely blend Mobil 5W50 with Mobil 0W40.

RDCR

I just looked at that thread LexVan linked, Motul Xcess 5-40 is no longer approved??

vantage

That's a bummer since I was at my mechanic this morning for an oil change and was about to switch to Motul Xcess 8100 5w-40 until reading this thread. Other Motul oils appear to be on the list though.

Does anyone know where I can find the most recent approved list?

xxrockmanxneoxx

Motul's website still shows approved A40

Yargk

Anything wrong with using a couple gallons of high octane unleaded race fuel per tank at the track?

Voyager6

Just make sure it is unleaded. I've heard stories about my local track's fuel farm and I will not buy gas there ever again. I now bring my race gas with me, purchased from a local distributor who keeps it in an above ground tank separate from the leaded race gas variants. I trust that far more than the track's fuel farm. I also get 100 octane unleaded at about $3.00 per gallon cheaper. No brainer for me.

As far as I know, unless the DME is tuned for the octane, the DME will not add timing, only retard if knocking is heard.

Yargk

Could be wrong, but I was thinking of avoiding having the timing pulled because CA only has 91 oct.

RDCR

I usually add 2-3 gallons per tank on track days but I can't say I could notice difference. I think the air temp has more influence then the octane level.

My first oil report was identical to the OPs except zero lead.

aryork

The last time I gassed up at VIR I almost put leaded in. I can't remember if that was 100 octane or what. I moved to another pump with higher octane than 93 (maybe 98) that said it was unleaded, and it was still $8/gallon. Maybe you got the wrong one by accident like I almost did or maybe the gas delivery guy put the wrong thing in the tanks before you were there.

I have not had the oil analyzed in mine (yet).

Voyager6

My indie shop's manager, who races at the same track as I do, told me that the track's fuel farm manager told him that the delivery trucks have put in leaded in the unleaded tanks and they could not guarantee that the fuel was lead free. The pump labeling didn't help. One pump has Sunocco Supreme sticker and unleaded stickers, which conflict, and the other has 360GTX sticker and leaded stickers. I can understand why the delivery trucks have issues.

My first cat meltdown occurred on the way back from the track after using their 'unleaded' race gas exclusively. Highway mileage dropped from 30+ to 23 MPG. The CELs started with the next drive. The Cat's ceramic cores were glossy black instead of grey or white.

I had the headers replaced in the off-season and the replacements started to fail after two DE weekends, but the cores still look light grey (but highway mileage was down to 26 MPG) I have been careful to avoid the track gas since then. The headers may recover now that the fuel mixture issue has been solved.

I had to diagnose the issues myself. The major cause was that the O2 sensors were causing the fuel to run really lean at low RPM and overly rich at high RPM under load. Not sure if the gas was the cause or I just got unlucky. During the debug phase, I went to catless headers to ensure I didn't ruin a third set of cats. The second issue was that the overheated mufflers had the steel wool packing vibrate and chip, creating a lot of metal dust that blocked flow by lodging in the ceramic wool packing. I dyno tested with an intentional leak before the mufflers and showed a 50HP gain up to 3500 RPM and a 20 HP gain at 6500 RPM versus no leak. So new mufflers went on, too. Unlikely to be random luck since both banks behaved similarly. An expensive lesson.

V6

aryork

LOL!