Randy V

Mobil 1 15w50 - I stock up when I can find it.

Castrol 20w50 in the boat and the BMW 7.

hacker-pschorr

I'm using this in the four cars that take 20w50.

There are three different version of VR1 though, non-synthetic, synthetic, and synthetic "not for street use".

The last one is rather difficult to find on the store shelf, so little chance of accidentally grabbing it. Lack of detergents mean it will not be good for a street car going 3k - 5k between changes.

When I run out of my current stock of VR-1 I'll go back to Brad Penn.

928mac

15 to 20W50 is what you need for the oil pressure and heat.
You need 1100 or more ZDDP for the cams so you dont tear them up when it Idles

Amsoil
Mobil
Valvoline
or
royal purple

are all top oils

Choose your poison

Oh, I use Amsoil and pay $13/L

PHIL928

If you would like to keep your car for a long time, use 20w50 with a zinc booster. (personally 20w50 Valvoline Vr1 Racing with a can of STP)
If you would like premature engine wear and like to do engine rebuilds every 150k km then 0w40 mobil 1 is for you.
Quick test to see if your oil is good:
Step 1 - drain old oil while car is hot
Step 2 - fill up the car with new oil
Step 3 - let the car warm up to operating temperature and take it for a gentle drive around the block
Step 4 - stop the car in idle
step 5 - Observe your oil pressure gauge, if it is higher than 2 bar the oil approves, the thickness of the oil is allowing for enough pressure to sufficiently squirt the main components.
If it is lower than 2 bar - park it up, drain the oil, apologize to your car, and put some 20w/50 in there with a can of STP.
step 5 - drive it like you stole it, because you know that engine is now protected and wear will be zero.

Mobil 1 is an over-branded American product, they signed a huge contract with Porsche back in the 80s so all of a sudden Porsche has to approve their oil as recommended, not because it's good, but because they get paid for it. It's a win win situation, Exxon get money from people buying the oil, Porsche reduce the lifespan of their vehicles so people will buy more porsche, and they get money from advertising mobil 1.
Am I right, or is the world a better place than I thought? Where consumerism doesn't exist and companies want to help you with keeping their products alive for as long as possible so that you can enjoy them, rather than inducing a premature death causing you to spend more money buying parts or a new car.
Use some logic people.

dcrasta

20w50 Castrol GTX.
Daily driving in this heat, I still see 2 bars of Oil pressure at idle.
No knocking, no heat related pinging, nothing usual.
Never let it get low.

antlee928

BTW, oil manufacturers will and do change there formulae from time to time. So always good to check on ZDDP values from time to time when using the same brand/rating oil over time.

Cheers

MarkRobinson

Race car: Amsoil RD50w
22k 86.5 Turbo: Mobil 1 15w50
3.6 Turbo 911: Mobil 1 15w50
944TS: Valvoline Racing 20/50 + one quart of straight 60w.

In 100d temps, I noticed on long hot days with the AC maxed in my 944TS, the oil pressure slightly below 2 bar. With fresh VR 20/50 with 1 quart being VR 60w, my oil pressure is at least 1/2 a bar higher with the same heat soak. I might start doing this to my 928 & 911 as well: throwing in a single quart of VR60w with my Mobil 1 oil change. Hmm.

dprantl

The good thing about Mobil 1 15W-50 is that it has the correct hot viscosity for a 928 (50) and also works well all the way down to ~ 30 deg F ambient temperatures. Most of the 20W-50 oils get too thick when it gets that cold. Amsoil and VR-1 racing oils may have better characteristics when racing or long high speed autobahn cruising. I would never use anything less than a xxW-50 oil in a 928 unless I lived in a place where the ambient temperature never exceeded ~85 deg F.

Dan
'91 928GT S/C 475hp/460lb.ft

GlenL

I'll run 5w40 oil during the Fall-Winter-Spring seasons and especially if plan to drive the P-car during the Winter. That'll include starts at down to -20F. The ice rinks are hard those days.

I've used Mobil1 "truck and SUV" and Amsoil "European car" for that. Nice oil pressure with both.

928mac

I have never seen my car below 3 bar even when its hot hot, but I replaced the main bearings when I first got it.
Bearing wear alows extra oil to leak off and then your oil pressure will be less.
It may be something you want to check if your down to 2 bars pressure but I'm not an expert on these cars.
Maybe Greg or Greg or someone with engine rebuild experience will speak up?

s4bill

I called Wal Mart and they sell the 5 qt container of Mobile 1 15W 50 (I believe it is 5 qt) for $26 something.

That is about 5.40 a quart.

robot808

My car came with Shell stickers.

So, which one is the good, honest oil company again?

dprantl

So you are saying an idle oil pressure of 2 bar is okay but 1.5 bar is too low? Prove it, and don't forget to show your work.

Dan
'91 928GT S/C 475hp/460lb.ft

GlenL

With variations in senders, gauges, voltages and ground it's hard to give numbers.

2 bar at hot idle is hard to achieve.

MarkRobinson

what I was saying is that under similar circumstances (same car, outdoor temp, engine load & AC on), my oil pressure is now consistently higher with the single quart of 60w added, all other variables aside.