what gas should I use
 

I have two options for gasoline at a station close to my house..... 90 octane ethanol-free or 92 octane with etahnal. Opinions welcomed!!!! 1981 SC ROW....

Wow, tough choice.

What year of car is it?

I use 91 octane and I have never had any problems. If you are not tracking the car or running real hard 90 is probably OK.

I see to recall reading on here that the CIS cars were particularly susceptible to ethanol issues. Unless your timing has been advanced, I'd be opting for the sober stuff. My SW chipped 3.2 requires 92+, so for a couple of years I was forced to go with the ethanol crap (even though 87 non-E was my choice for everything (PARTICULARLY for my smaller two-cycle stuff). Thankfully, AT LAST, I can now source 93 non-E for my Carrera and bass boat from two different place at reasonable prices...very happy camper these days :)

ps: Did I mention that ethanol gas sux....WHEN is the nonsense gonna end???

SC 3.0 engine is lower compression, I know the Us models are 8.5:1...not sure about ROW.

90 with no ethanol is a fine cocktail for that little baby :)

Count your blessings, in Kalifornia, unless you buy it at the track, all pump gas has ethanol.

BTW. US and ROW models '78 to '79 8.5 to 1
US models '80 on 9.3 to 1
ROW '80 8.6 to 1
ROW '81 on 9.8 to 1

Other than marinas or airports, I know of only a few places that have "a single pump" with the good stuff (87 and now 93). I go out of my way to patronize these stations.

Your fine with either albeit with the choice I would go with non ethanol. Where I'm at it all has ethanol
Ernie 81sc

US compression ratio was 9.3:1 tuned for regular.

Sources for ethanol free gas.
Ethanol-free gas stations in the U.S. and Canada

Options in CA are very limited. Here in OR we've got lots...

For '80 on, I failed to specify mine, what I was referencing, is a '78.

AV or racing gas 101octane is fantastic stuff @ $9.00 a gal. is great

We bought a '82SC in '86.
First tank of gas was "gasohol" as it was called then, had a constant noise from the front that sounded like a buzzer. Dealer, said noise was the fuel pump, caused by ethanol. Quit using it, noise went away

I have used ethanol gas since mid 70's (and still do). Our '97 4Runner has 265K miles on it with a steady diet of ethanol. Never had a problem with any car except that one time.
Bob

Unless you've played with timing or compression ratio, regular gasoline is fine. Around my neck of the woods, that's 87 octane. Of your two choices, I'd go with the 90 octane ethanol free.

Hugo

Has anyone here mixed 91-93 octane with Cam2 racing fuel? Cam2 is 110 octane. Just wounded if mixing 8 gals of street gas with 4 gals of Cam2 is good for a early 911 2.2/2.4 motor? Or Is it bad for the motor?

Wow. Lots of bad info on this thread.

For the record, an '81 ROW SC has a compression ratio of 9.8:1 and Porsche specified that the fuel to be used was 98 RON. That's roughly equivalent to 94 in the states, give or take.

If I owned that car I'd use the highest grade non-ethanol fuel I could get and I'd probably add an octane booster to it. I'm not talking about the useless crap you get in the little cans at the auto parts stores. I'm talking about buying 5 gallon cans of something like what the fuel companies use for octane boosting, or used to use before the EPA went nuts. You need to find a guy with a race fuel business and buy him beer.

An early SC is fine on 87, but the later US cars need something a little higher. When in doubt, take 60 seconds and read that part of the owner's manual.

JR

Go ethanol free, save the hootch for your belly!

Seriously though, the octane is less of a concern than the potential of water entrappment in ethanol as well as potential seal issues not to mention the issues with ethanol blends on the oil film. Yup, it actually can be a concen that many don't want to talk about.

The fact is that many oil blenders are looking to produce oil that is beyond CJ-4 compliant which means many are looking at alternative add packs - some of these may not be ethanol friendly. I say 'may' because there hasn't been enough work done into the long term ramifacations yet. And considering the polarity of some of this technology I would be cautious. The whole thing has been going very fast compared to the past developments. Hopefully the gubment will relax their notion of increasing hootch at the pump. One can only hope...

As for octane boosters, thats why ethanol is added in the first place. You can boost the octane rating with non-ethanol additives (such as xylene and tolulene which is north of 115 octane compared to ethanol which is around 108 I think) but your seals really won't like it. The only way to legit boost the octane is at the refinery.

When pure gas isn't available it's a good idea to use Marine Sta-bil.
-C

True dat...

And they could do it, if they wanted to. I attended a Ferrari event some years ago and Shell was kind enough to show up at the track event with a tanker full of 95 octane. Free, all you can use...

How about a little MTBE for the needy... ;)

JR

Use only enough octane to prevent detonation, more is just a waste and will actually yield less power. If I am going to be doing plain Jane freeway droning I will use 87 and stay off the throttle until I get a stiffer mix into the tank. Nothing wrong with ETOH, unless you let is sit and collect water and corrode the plated steel parts it comes into contact with. The majority of fuel related issues come from not driving the car.

A buddy told me about the Pure Gas app (iPhone) and I use it to find non-ethanol gas. My local Cenex has 92 pump and I run it exclusively. Smells good too.

Here in Brazil, the mandatory percentage of anhydrous ethanol in gasoline is 25%.
We do not have much choice.