M. Requin

Royal Purple HPS 20W-50, because of the results of an Aussie motor club tribology study I read about which was referenced on this forum.

granprixweiss928

Brad penn 20w50 because greg brown said so

OTR18WHEELER

Castrol 20 w 50.. Dino

Because it's good,
I don't care what Greg Brown uses.

These engines were not engineered for synthetic oil.

Bill Ball

M1 15W/50 because it meets the requirements and works just fine. I've felt no need to get into boutique oils.

JET951

20w-50 in both my last century Porsche's ( 1986 928S & 1993 968 )

Why ? = because its the correct oil viscosity ( Oil Film Strength ) for a last century Porsche with high loaded flat tappet designed OHC for our ambient temp range & at high RPM ( Oil hot ) protects No2 /6 ( 928 ) & No 2 ( 968 ) con-rod bearings & crankshaft thrust bearing/s

And Sean ( Jet951) runs 25w-60 + "STP blue" all year round in his 3.0L E85 Big HP 951 , to & from work ( commuting ) and to & from the track ( competing in Supersprints etc ), year in and year out

Regards
Bruce Buchanan
Buchanan Automotive

The Forgotten On

Valvoline VR1 20w-50. It was available everywhere, cheap, and had the zinc I needed.

I have a stash of it for 2 more oil changes as it was outlawed in California for having too much zinc for a street oil It was a great oil while it lasted.

FredR

Shell Helix HX5 20w50 mineral oil plus a tub of STP oil treatment.

Why:
1. Limited availability of oils I trust. Mobil 1 15w50 not available here- they only market 0w40 and that is not going in my motor despite Porsche recommendation.
2. In our high temperature climate [lowest ambient 15C highest circa 50C] I believe it would be stupid to run with anything less than a 20w50.
3. The STP helps with high operating temperature protection and adds additional ZDDP given I could not get clarity on the Shell ZDDP content [note: too much ZDDP is not a good thing].
4. Motor internals very clean as are cam lobes.
5. The PO of my motor used Castrol 10w60 synthetic up until 1998 when I purchased my late S4. I found this difficult to source, then used Redline 20w50 [good ZDDP] available in Dubai but then the agents went bust or something so decided to source something locally and migrated to Castrol GTX 20W50 mineral oil until that seemed to disappear from the local market so migrated to the Shell that I have used for the last 8 years. I change the oil every year or so [ or 10k km max].

When it comes to lubrication there is a lot of mythology. With lubrication either you have sufficient or you do not- failure occurs when the latter happens and pretty damm quickly. Use the oils/specs recommended by Porsche and you should not have a problem.

Take the car outside the design envelope, put stickier tyres on it, go round bends faster, rev the motor to 6k+ rpms in the [Left hand?] bends on a race track and the elements for lubrication failure are present- more so GT cams perhaps that are more inclined to want to be revved. Then you need a more resilient lube such as Mark Kibbort uses- he does not have too many blown engine issues [zero I know of] and he probably beats the snot out of his 928 motor about as hard as anyone else on the planet.

Rgds

Fred

marine928

I am a little outside the box, have been using Lubriguard 20 50 in my fleet vehicles for over 15 years been using it in my 1972 Datsun 240Z and in my 87 S-4 because of the proper ZDDP and other characteristics. This site can answer just about any question you have on oil properties.

See chart: https://www.google.com/url?sa=t&rct=...31286987,d.eWE

mike77

Millers CFS 10w50 fully synthetic. Because it has 1200 ppm ZDDP and the 10w offers good cold starting protection for our Scottish winters

http://www.millersoils.co.uk/automotive/tds-automotive.asp?prodsegmentID=150&sector=Motorsport

The Deputy

20W50 - brand unknown.

The 10 reasons why...

Reason why #1...it's the correct viscosity.

Reason why #2...because the boss said "a vendor dropped off a 55 gallon drum and were not going to use it in the fleet vehicles...so you guys help yourself".

Reason why #3...because it's free.

Reason why #4...no issues on start up (78 clattering).

Reasons why #5, 6, 7, 8, 9 and 10...because it's free.

Like I say, don't know the brand...so I'm not sure if it gets the GB stamp of approval...or not.

Brian.

Wisconsin Joe

Not the only one.

I have a Suzuki Katana (motorcycle) and the guys on the M/C forum suggested diesel oil. High detergent and good Zinc & Phosphorus. 40 weight is good enough for me here in WI, hardly ever goes above 90, plus my A/C is out so I don't drive it when it's that hot.

Pressure is good, at all times.

I get it at a good price from a friend who is a big truck tech (he gets it in bulk).

I run it in the 928, 944 & motorcycle.

Koenig-Specials 928

Royal Purple 20/50 because of the zinc content and availability

Arnoud

- Use to be: Shell Helix Ultra 10W-40. For overall good performance from -25 to +35 Celsius.
- Switched several years ago to: Valvoline VR1 racing 20W-50, good ZDDP levels while I could not longer find out what those were in Shell oils (and no longer driving during the winter months).

the flyin' scotsman

Change oil in the spring to 20w50 Amsoil Zrod or Mobil 1 15w50 full synthetic.

Just before parking for winter change to Castrol 20w50 (or whatever 20w50 is on sale) so it sleeps all winter in fresh oil.

jcorenman

Brad Penn 20w50 because it has all the right stuff, is reasonable priced, and viscosity doesn't change with more miles.

We usually change every 3-4K miles, recently let it run to 6K (x-country trip to Vermont) and Blackstone said nothing changed-- no viscosity drop with higher miles that we've seen with other mineral or partial-synthetics.

Previously Torco TR1 and SR1, before that Amsoil (ARO) and Mobil-1, all 20w50 or 15w50.