brianrheffron

A local discount outlet is offering 15W40 part synthetic oil rated API SJ/ CF-4 at an excellent price. The 928 motor has by modern standards a relatively low specific output of 64 bhp/ litre. SJ oil is a big improvement on the oils available 20 years ago and recommended when the car was new. Is there any good reason why I should not use this oil as opposed to the much more expensive Mobil 1 ?

Mrmerlin

how often do you change the oil???
You really could use Dino for that matter, as long as it has the correct ingredients and its changed every 3000 miles

hacker-pschorr

My three rules of buying oil:

1. Pick a good name brand synthetic
2. Buy a viscosity that fits your driving and climate
3. Stay away from all oil with a CF-4 rating

CF-4 is the "new" environmentally friendly rating with low ZDDP numbers to protect catalytic converters.

Do a search for ZDDP in every forum, there are many threads on this.

Or read this:
http://www.cam-shield.com/acatalog/FAQ.html

EDIT - +1 There are some good dyno oils out there, like this:
http://www.le-inc.com/products.jsp?productID=258

AO

X2

hacker-pschorr

Good point, in the spirit of "budget oils" we can just follow Mark's advice:

https://rennlist.com/forums/3099439-post51.html

James Bailey

The part synthetic oil is like the "beechwood aged" beer......the beer spends 18 days in huge aluminum tanks in a secondary fermentation near the end they toss in some beechwood chips (preboiled and processed to remove all flavor) which fines the beer causing all the yeast to fall out of suspension. Unless the synthetic mix states how much is synthetic it need only be a few drops in a barrel ! It is all just marketing.......save your money run plain old oil preferably with the ZDZP.

Mike B

Great analogy Jim

WallyP

For most of the 928s, Porsche recommends changing the oil every 15,000 miles or 12 months. Once a year seems adequate to me...

SeanR

x2 or 3.

had several tests come back from Black Stone Labs and all were fine after 8k 10k and 13k (boutique oil on the 13k one) Rest were M1 15-50

deutschmick

I equate budget oils with budget tires.

YMMV

blown 87

Just FYI, a good friend of mine, Mike Grubber who is the NHRA racing directer for Valvoline told me this week that since the switch to SM, Mobil one IS the worst oil on the market, came as a big surprise to me, because he had recommended it before.
He said do not use it in any flat tappet engine like our 928's.

For what it is worth, I am no longer going to use it or any SM oil in any cars.

Greg

GregBBRD

Torco or Brad Penn.

I'm just going to pass along one thought:

The price of oil is not going to be a significant part of your 928 maintance costs.....

blown 87

The Valvoline Racing synthetic is supposed to be good also.
From what Mike said, more than a few of the manufactures are going to start making SL oils again because of the issues with the SM's

blown 87

Neither is changing it more often than some here do.

hacker-pschorr

Every fall before you put your car in stoarge, take an oil sample and send it in*:

http://www.blackstone-labs.com/standard_analysis.html

$22 and you might find out there is no reason to change it next spring.


*for us crazy bastards who live in the snow belt.