1999Porsche911

As I mentioned above...it is the 15W that will keep your lifters from excessive bleed down and losing pressure. Running water in them is why so many complain of rough idle and noise after the car has sat for long periods of time..

Palting

This is fun, but I think we are getting further and further away from the topic, into an area of nebulous opinions that are well intended, well thought, possibly right/wrong, but ultimately do not answer the question raised in the thread.

Does Penguinking have a problem or not? I think he does. His pressure is too low at the track. What is the solution? I think the 3.4L oil upgrade kit if still available, though it is pretty expensive and entails shipping one of the heads. Not sure the BK deep sump will work. Since 1999Porsche911's much beloved 15W50 seems to be in the OK list, should be OK to try to see if it works. Betcha it won't, heh-heh .

bgiere

your the boss, i obviously can't add any help in this situation being so WRONG and all.

bgiere

https://www.pca.org/tech/tech_qa_question.asp?id={D628EF12-276A-48C7-BAE1-4BC29E8F7398}

i feel better now...he's wrong too! hey man, just tryin to help and learn something myself!

1999Porsche911

If starvation is the cause of the low pressure, 15W50 oil will not help increase the pressure, as you said. However, it will prolong the protection of the metal parts that are being starved of oil for a longer period of time than the 0W40 will.

bgiere

https://www.pca.org/tech/tech_qa_question.asp?id={6AAD8903-6A72-40F4-9A1F-9D021DD24DB2}

more i sayeth not! good chatting with you!

Palting

I actually read this one! Thanks for the link.

penguinking

hmmm...interesting read.

maybe this is a better question: is there a way for me to tell if i AM getting oil starvation in the turns?

bgiere

https://www.pca.org/tech/tech_qa_question.asp?id={4F59AC7A-4887-4BB0-9F0D-749DDC0F8634}

sorry it won't hyperlink...anyways, this issue has been dicussed for awhile, started right after the M96 engines came out...Porsche must've seen a circumstance where there can be enough cornering force to briefly interrupt oil supply but i have not heard of anyone actually experiencing it. Most of the engine problems we see have been because the owner used the wrong oil viscosity...i will not say which viscosity they used for fear of insulting the omniscient. it is safe to say the oil was just too viscous...i have a guess...i think the oil pressure gauges and sending units in the new cars are very "quick" to register changes...combine that with a slight throttle lift and you will see a gauge move in a corner maybe?? just a hunch...lately there have been many,many drivers with the water cooled engines at the track, both PCA and NASA and they have been holding up well! Good luck to you and i hope this sheds some light.

bgiere

one last thing. i posted a viscosity question to a tribologist (oil guru) regarding another issue i was working on...FYI, here is his opinion. I realize it was for air-cooled app's but interesting none the less:

"A thicker oil will not transfer heat as well as a thinner oil and it will increase "intrafluid" friction.

Think of all the energy that's required to stir a glass of honey, vs one of water. The first law of thermodynamics says that energy can not be lost or gained in a closed system, only converted. The extra energy need to pump and shear (deform) a thicker lubricant therefore goes directly into heating the fluid and the engine surrounding it.

I'd be most concerned about the effect of thermal expansion in an air cooled engine and having the Al pistons bind in the cylinders, as well as very high seal/gasket temps (they'll age faster at higher temps). A 5w-40 or 10w-40 will reduce your peak oil temps by 10F-20F and the car will put out noticably more power. Oil pressure (which determines bearing protection) and oil film thickness (which determines valve train wear) will really not be that much different with the 5w-40 or 10w-40, since the oil is running cooler.

If you have access to Redline, I'd also consider their new 5w-40 synthetic...it's a very shear stable formulation and should work well here. Call Dave at Redline and pick his brain about this for 10-15 minutes - I think he'll confirm what I'm saying."

sincerely,

Ted Kublin
www.lubedealer.com/Dixie_Synthetics
MSME, Georgia Tech, class of '81

penguinking

any 996 C class racers wanna chime in and let us know what kind of oil/wt you're running? if it can hold up to PCA racing, its probably overkill for the occasional DE's i do

bgiere

had a discussion with an anonymous source who does oil testing for a major oil company...he said that the 996 cups in Australia run Fuchs Silkolene 0w20 with no apparent wear. now, keep in mind the engines are rebuilt after 25-40 hours...but the results would astound you he said. anyways here is a blurb on 996's with a little talk about what the cup 996 is running at that time.

https://www.pca.org/tech/tech_qa_question.asp?id={EB7C9701-A45B-4B4A-AA5D-64D8B22E76EA}

TD in DC

Do the 996 engines have oil pressure relief valves? If so, you might want to check that if you are having an oil pressure problem.

LVDell

0W-20?????? No wonder they have to rebuild every 25 hours!

bgiere

yeah the 0w20 would make even me nervous i must say...but, supposedly it has a film strength and HTHS number that is better than alot of 50 wts.....so i am told. i ran some 5w20 Redline in my old car...it was absolutely fine. sure did rev nice!