Ish_944

Would you gents consider 5w-50 too thin? I'm running a high quality oil (Liqui Moly) year around and I always get 3.5 bar oil pressure at warm idle. Temperatures range from -20 to 40 Celsius at the extremes here.

mdnt08

This is great information. I was just researching the use of Shell's Rotella T Diesel Oil since folks mention using it due to the Zinc content. 20-50w FTW

hb253

Let's not allow pesky facts to get in the way :-)

I run Rotella T6 5W40 in my 968 (and 928) and oil pressure is no different than when running 20W50 - winter or summer.

For the curious, head over to the 928 forum to read a thread with the same subject.

Hugo

JET951

Hi Hugo , it is impossible to get the same engine oil pressure at the same oil temp from a 5w-40 and a 20w-50 , that's why wee see in hot weather 928 ,928S, 928 S4's , 928Gt's , 928GTS's , 944 ( all versions ) , air / oil cooled 911variants ( all last century Porsche's) that are on a 5w-40 ,their oil pressure Warning Light is glowing at idle ( Not Enough Oil Pressure ) when the oil temp is above 100 deg cel or so ( Basic Physics ) & in this low oil pressure state the engine will NOT generate enough oil pressure at high RPM to fully protect the con-rod bearings ( big end bearings as we call them ).

The other thing you may not know ( understandable ) is that on you're 928 , the 928 in the dash oil pressure gauge only reads up to 5 Bar , but the 928 engine ( all versions ) the oil pressure relief valve opens at 8 Bar , so the 928 should have a 0-10 bar oil pressure gauge just like the Porsche 931 had and the early 911 series did ( 0 - 10 Bar gauge ) , so you are getting an incomplete reading when you see the oil pressure gauge "Pegged " as people say at 5 Bar , the gauge is incomplete & gives you the wrong impression .

All very very very very simple physics , this is not rocket science

Regards
Bruce B

ealoken

My 951 is getting Gulf 20w-50 this year, no 10w-60..

Raceboy

I use Motul 300V Le Mans 20W60, one of the very few oils that endurance teams actually use in their engines (most other are just marketing names).

924srr27l

924srr27L's 205bhp 2.7 8v used running in oil for 50 miles, then 20W50 Classic (1950's low deterent, high ZDDP) Mineral MOTUL Oil for the next 3000 miles

Then since then Joe Gibbs XP5 Semi-Syth 20W50 Racing Oil every 1000 miles, (And soon to be after every 2 hour Endurance Race for this year)

The Oil pressure is very good and the consumption very low.......

R

Wisconsin Joe

Well, I'd be a bit skeptical of a manufacturer's site. Tends to be more advertising than actual unbiased info. They want to sell the expensive stuff.

Entered "diesel oil in motorcy..." and it auto filled to "Rotella diesel oil in motorcycle" and gave this:

https://www.google.com/search?q=rote...hrome&ie=UTF-8

V2Rocket

$18/LITER

Dave951

Yeah a while back when Valvoline VR1 was getting harder to find locally I came across the Motul stuff and was sticker shocked as well.

JET951

Hi Wisconsin Joe , thanks for showing me the interesting array of what people choose to use, in this case using diesel oils in motorcycles that are not diesel , I had never heard of it before , in regards the motorbike /s that you own or have owned , what would be the overage price difference between the diesel oil & the dedicated motorbike engine oil in doing one oil change ?

And in you're opinion ( in you're state ) or USA as a whole , what percentage would you think qualified motorcycle mechanics recommend not using proper motorcycle oil & instead recommend using diesel oil in a non diesel motorcycle engine

Wisconsin Joe

Well, price is about 4x for the synthetic vs diesel. 1 quart of the snyth M/C stuff goes $10 - $12, and I can get a full gallon from a friend who runs a shop for that much. My M/C takes 4 quarts on a change.

But, cost really isn't the driving factor. I change the oil once a year and the cost of an engine (or even a rebuild) makes the $35-$40 difference for a yearly change minor.

I like the detergent properties and the somewhat heavier weight. The narrower range (15-40) is also supposed to be more stable. My understanding is that the wider the range (say 0-40 or 5-40) the sooner the breakdown. For example, the M1 0-40 recommended for Cayennes will "shear down" to 30 weight within 5k or 6k miles. This has been discussed to death over in the Cayenne forum.

I have no clue what percentage of mechanics suggest doing what I do. I don't even suggest it myself (I'm not an expert). I suggest other people do their own research and make their own choices.
i have also experienced "qualified mechanics" who have no clue about stuff that doesn't involve "nuts and bolts" wrenching. Stuff like fuel additives, using ethanol gasoline, and...

Oil choices.

Luis de Prat

In Europe Mobil1 sells 5W-50 grade, so you can park overnight at the ski slopes and not worry about starting the car the next morning. When summer comes, the same oil will do.

Arominus

Unfortunately that is not commonly available here. My goto "get anywhere" is 0-40 and 15-50 m1.

floatingkiwi

Bruce B - nice info. I'm running a standard (with sump baffled) 944 S2 race car here in NZ. The other guys all seem to use the 5W-50 mobil 1 but I believe thats not really good and have made the switch to Penrite Racing 15W-50 for zinc levels more than anything else (as the hot vis is still the same).
Our ambients are around the 15-25C range and my car seems to keep its cool very well on race days compared to some of the other 944 guys.

Thoughts on my selection or penrite in general?
Penrites own selector even gives you the "preferred" oil as 5W-40!!

Cheers