SaabCentral Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
546 Posts
Discussion Starter #1
Saabers-
My car: 2006 9-5 2.3T non-tuned. Recently took a road trip and filled up with locally-available 91 octane non-ethanol as opposed to the 93 ethanol gas I had been running. On the trip, at steady highway speeds, the SID seemed to indicate I was averaging about 2-3 mpg greater mpg (around 32-33) than on the higher octane 10% ethanol gas that I'd get about 30 mpg on according to SID.

I'd enjoy reading your thoughts on these apparent results as well as your thoughts on longer term impacts on spark plug deposits and DIC performance running higher octane ethanol v. the lower octane non-ethanol fuel. Thanks in advance.
 

·
Super Moderator
Joined
·
1,446 Posts
Ethanol has a higher octane rating, but lower BTU content per gallon. The more E content you have, the worse your gas mileage will be. I love E85 for its high octane rating and ability to make more horsepower, but your setup has to be tuned to take advantage of it. In your case, there is probably little benefit.
 

·
Registered
Joined
·
376 Posts
Joshinator99 is right, I just want to add that on a stock car, I'd still prefer 93 E10 fuel over 91 E0. Even if gas mileage might be a tad worse, your engine will be happier and less prone to knock and detonation. Saabs love high octane and E10 has virtually zero long-term impacts.
 

·
Registered
Joined
·
546 Posts
Discussion Starter #4
Thank you very much gentlemen. I’m headed back to 93E10. I don’t know if this has anything to do with anything but I do know that I run a 45-year-old motorcycle and the ethanol gas, which was predicted to cause all kinds of troubles, actually seems to significantly reduce varnish and build up on my motorcycle carb jets and floatbowls. And I still have this self concocted theory that ethanol class gas actually results in reduced deposits on the spark plug electrodes. It’s all good, thanks again.
 

·
Registered
Joined
·
343 Posts
This is true with any car, day one of ownership... read the owners manual. It will tell you this car is rated for 89,91,93 octane. And thats what gas you should use as fas as ethanol... tomatoes, to-ma-to-s lol. As for why, the octane rating is not about how good the gas is, its the resistance to ignition. 89 is the easiest to light whereas 93 is the hardest to light. Your spark plugs are rated for 93 octane and running anything else will shorten the life of your sparkplugs as well as add to carbon build up on pistons and valves. Thats my two sence.

Side note there is a TSB (Technical Service Bulletin) out on these cars to only use shell or Chevron gas because others can cause spark knock and detonation.
 

·
Registered
Joined
·
715 Posts
I do not trust the mileage readout. I keep a calculator in my car. I divide the gallons into the miles driven, and reset the miles every tankful,
 

·
Registered
Joined
·
715 Posts
I do not trust the mileage readout. I keep a calculator in my car. I divide the gallons into the miles driven, and reset the miles every tankful,
Also, when I was adding about $10 worth of non ethenol my gas gauge would stick for weeks at a time. It stopped when I stopped adding non E gas
 

·
Registered
Joined
·
9,227 Posts
That TSB only seems to say that Top Tier gas should be used. At least in the US, Arco and Costco's gas is also rated as Top Tier. Top Tier is also only a rating for the detergent package. It has nothing to do with the quality of the gas, or the octane.
 

·
Registered
Joined
·
5,927 Posts
My experience is different somewhat I generally use 94 octane ethanol enhanced (10%) but to store the one car that uses 94 gasoline exclusively due to its tune configuration I fill with 91 octane non ethanol shell before putting it away (3/4 tank) . The Saab I use year round, and generally use 94, but in winter I use 91 Shell. The lower the octane without knock, the more power you make. So that's good. But the real reason I use 91 ethanol free in winter, is that the car runs fine without knock due to ambient temperatures, and its CHEAPER BY A LOT!! I also run the same 91 ethanol free in my lawn tractor, snow blower and leaf blower etc, along with rammers and tampers that I service for a friend. Although this equipment does NOT need the octane, Shell 91 is the only ethanol free gasoline I can buy here. Ethanol separates out over time, ( 2 months for E10, and E85 three weeks, Pure ethanol three days) and I get really bored with cleaning/changing carburettors due to the contamination from ethanol. And seafoam doesn't help. Honda say to store power equipment with fuel shut off, and motor run until carb is dry. FYI
 

·
Registered
Joined
·
3,576 Posts
Shell 91 is the only ethanol gasoline I can buy here.
I think you meant to say NON ethanol gasoline.

My Saab indie suggested use Shell V-power non ethanol years ago, my cars, boats, Deere and yard tools all get ethanol free gas and seem to like it, especially the Kawasaki engine in the Deere.
.
 

·
Registered
Joined
·
5,927 Posts
I think you meant to say NON ethanol gasoline.

My Saab indie suggested use Shell V-power non ethanol years ago, my cars, boats, Deere and yard tools all get ethanol free gas and seem to like it, especially the Kawasaki engine in the Deere.
.
edited thank you
 

·
Registered
Joined
·
343 Posts
I may have missed the line... but it does specifically state shell or Chevron. Although on your side of the coin... it says top tier which everyone says they have now. From personal experience... I put BP gas in my suburu once... never ran right after. So I am pretty anal about what gas I'll use. Chevron, texico, and shell... in that order.
 
1 - 13 of 13 Posts
Top