nile13

What gas do people use in their 993? Is premium required? Does it give any benefit? What does the manual say about it?
Thanks!

Viken

93 pump octane. Read this too: http://www.rennsportsystems.com/2a.html

nile13

I do not see an answer to my question in that article. It discusses several interesting things that I'm aware of, but not the octane number for a street driven car.
Am I missing it?

Phil

I am pretty sure Viken answered the question. "93 pump octane"

nile13

Than 93 it is. Thanks, Viken and Phil!

Autobahn

Are there any differences between European and US octane figures? Over here Porsche cars must use at least 95 octane but Porsche recommends the use of 98 octane gas.

Viken

Yes, there is. Ninety-eight octane over there is approximately the same as ninety-three here.

nile13

The difference is actually somewhat hard to quantify, but the rule of thumb is subtract 5 points from European octane number to get American number.
98, the highest pump gas in Europe is equivalent to 93, essentially the highest pump gas in the States (although some Sunoco stations have 94 as well). Your 95 corresponds to our 89, which is in reality a mix of our 87 and our 93 (your 92 and 98).
I hope that's less confusing than it seems.
There are also a number of issues with sulfur content, MBTE and other fun stuff in US gas, different summer and winter formulations, different octane numbers at higher elevations, like in Colorado, but that's a different story.

phatbut

I have yet to see 93 Octane around my neighborhood. I've seen 100Octane, but it's considered racing gas.

Anybody know of a place who carries 93 octane in the greater Los Angeles area?

Viken

There is none in California. You can just use 91 octane which is just fine.

nile13

Is it because of additives there, or some other reason?
We have 91, 92, 93 and 94 here on the East cost, with 92 and 93 being the most common "Premiums".

Autobahn

Thanks Viken & Nile,

Shell over here sells 99 octane gas but it is quite controversial over here since according to most people the Porsche Motronic cannot adjust for the use of higher than 98 octane gas. But I have read quite frequently on this board that quite a few people have experienced power gains when using 100 octane gas. I am slightly confused!!!

Viken

That is correct. The ECU will only compensate for lower quality gasoline.

That is NOT true. Anyone who thinks that 100 octane provides increased performance in an engine otherwise tuned for something less than that, is likely trying to justify spending $4.50 to themselves.

Autobahn

Thanks again Viken.

Dirt Track Racer

Um, isn't this the equivalent of saying something like:

In fact, the difference is easy to explain (but not easy to exactly figure out). In the US we add the RON and the MON rating and then divide by two to get the average octane rating of fuel. In Europe, they just use the RON number to rate their octane. FWIW - the RON number will always be higher than the MON number.

Incidently, race fuel in the US only uses the RON rating too. So that 122 octane leaded fuel I run in my late model car is really equal to only about 114 octane street gas.

dtr