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DZGunner · Joined: 18 Nov 2014 Posts: 191 Location: Great white north

This may seem like a dumb question but i'd like to know what viscosity oil you guys use and how often your oil changes are. My dad's been putting 10w-30 in this 79 NA and it's been running like a champ through summers and winters. I'm just not sure if the car being turbo'd would need something a bit heavier or what. Also how many miles do you guys change it out.

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Oh, boy, oil thread! People get SO PISSED!

Porsche just changed their factory recommendation for oils. Newer cars are listed specifically by model in the TSB, older cars are included (I presume) in the catch-all category "all sports cars," which recommends 0w30. Boy, does everyone freak out over this!

My manual says 10w40 natural oil for most conditions, but I run 5w30 LiquiMoly (high quality German synth). People will be running in here shortly to say this approach is crazy, and that turbos "need" 20w50. Well, my 931 runs great on the LM, and I would argue that the advances in synthetic oil obviate the need to protect through viscosity the car doesn't need. Higher viscosity obviously reduces efficiency and power. Insistence on 20w50 is definitely "old skool" thinking.

I change at about 3000 miles, and after several years of hard use on a fresh rebuild, there is still ZERO turbo smoking, and when you pop the valve cover, what you find underneath looks brand new.

A word on intervals: the hyper long intervals claimed by the synthetic oil manufacturers are probably accurate, but are marketing tools to justify the higher price. In reality, it is the filter life that has the greater impact on change out intervals when using synth.

Let the games begin!
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

There are 3 things that people shouldn't discuss because they always lead to an argument and you're never going to change the others mind..... religion, politics & oil. Lol

You can run whatever viscosity you want as long as you can make adequate pressure under all circumstances the engine is ran in. That can vary from engine to engine even of the same type. Besides cleanliness, Interval is a product of the oils ability to fight breakdown, that changes depending on what you use. 3-6k may be fine for street use but would be way overdue in a track car.
The factory guidelines for specific models, in my experience, are pretty accurate. Hard to go wrong if you follow the guidelines.

DZGunner · Joined: 18 Nov 2014 Posts: 191 Location: Great white north

lol, the 928 board on rennlist had a few threads pages upon pages in length over arguing the best type of oil.

The car will be run exclusively in the summer, and I don't want to go synthetic just because of price, I mean, if I just did a full engine rebuild I'd do it, but I haven't even run the car yet so before I dump liquid gold into it I wanna know that its not going to burn it all up first.

I'll prob just run 10-30 like I have been on the NA. Thanks for the input guys.