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Republican in training
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quote:
Originally posted by TMats:
We have a car that says it wants 93 octane gasoline. I’ve yet it see anything higher than 91 offered for sale out here. Exxon seems to reliably sell ethanol-free 91 octane fuel; 85 and 88 octane have some level of ethanol (and yes, for some reason, Exxon sells 88 rather than 87 here).

What car is this? Are you sure about that? That is a bit surprising knowing that several parts of the country can't even get 93 octane...

I'd probably go with the ethanol free 91 to answer the OP's question. Unless it was a very new high performance car that likes higher octane.


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I like Sigs and HK's, and maybe Glocks
 
Posts: 2263 | Location: SC | Registered: March 16, 2011Reply With QuoteReport This Post
Legalize the Constitution
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911 4S


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Posts: 13166 | Location: Wyoming | Registered: January 10, 2008Reply With QuoteReport This Post
Republican in training
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Originally posted by TMats:
911 4S

at this point I'm going to need to borrow your car for a month or two to do some thorough testing... Red Face


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I like Sigs and HK's, and maybe Glocks
 
Posts: 2263 | Location: SC | Registered: March 16, 2011Reply With QuoteReport This Post
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Back in the day, 426 hemi with two 4's, used to drive about an hour to get racing fuel, if I remember correctly it was 104 octane. I could literally go thru a tank, and rear tires, in about 30 minutes.
 
Posts: 1579 | Location: Ohio | Registered: May 27, 2008Reply With QuoteReport This Post
Page late and a dollar short
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quote:
Originally posted by TMats:
quote:
Originally posted by egregore:
quote:
We have a car that says it wants 93 octane gasoline. I’ve yet it see anything higher than 91 offered for sale out here. ...

You give your location as Wyoming. Wyoming's high elevation (its lowest is still over 3000 feet) creates less cylinder pressure and the octane rating can be lessened with no problem.
Yeah, pretty familiar with that


Used to be that the EPA considered anything about 4000 ft above sea level as "high altitude". Many cars and trucks built for high altitude areas had different carburetor jetting and choke settings together with advanced ignition timing. In GM dealerships we could advance ignition timing 4 degrees on certain engines and reset the choke and affix a label adjacent to the factory emission label under the hood stating the work done. One of the other things was Octane Ratings that were usually one or two points below lower altitude fuel for example 87 Regular in high altitude was now 86 octane. Also in the early 1980's some shady fuel distributors were adding a higher percentage of Ethanol to the gasoline than legally permitted, the only way they were caught was that the vehicles using that spiked fuel were more prone to vapor locking and upon testing they were caught.


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————————--Ignorance is a powerful tool if applied at the right time, even, usually, surpassing knowledge(E.J.Potter, A.K.A. The Michigan Madman)
 
Posts: 8066 | Location: Livingston County Michigan USA | Registered: August 11, 2002Reply With QuoteReport This Post
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quote:
Originally posted by shovelhead:
quote:
Originally posted by TMats:
quote:
Originally posted by egregore:
quote:
We have a car that says it wants 93 octane gasoline. I’ve yet it see anything higher than 91 offered for sale out here. ...

You give your location as Wyoming. Wyoming's high elevation (its lowest is still over 3000 feet) creates less cylinder pressure and the octane rating can be lessened with no problem.
Yeah, pretty familiar with that


Used to be that the EPA considered anything about 4000 ft above sea level as "high altitude". Many cars and trucks built for high altitude areas had different carburetor jetting and choke settings together with advanced ignition timing. In GM dealerships we could advance ignition timing 4 degrees on certain engines and reset the choke and affix a label adjacent to the factory emission label under the hood stating the work done. One of the other things was Octane Ratings that were usually one or two points below lower altitude fuel for example 87 Regular in high altitude was now 86 octane. Also in the early 1980's some shady fuel distributors were adding a higher percentage of Ethanol to the gasoline than legally permitted, the only way they were caught was that the vehicles using that spiked fuel were more prone to vapor locking and upon testing they were caught.

I worked at a couple of different GM dealers in the Denver area, as a young man, back when cars still used carburetors, rather than fuel injection systems.

In preparing new cars for delivery, the first thing we did was pop the plastic covers off that sealed the air/fuel mixture screws of the carburetor, put a tachometer on the engine and adjust the settings for highest rpm at idle and smoothest running. The engines typically ran like pigs at the factory settings.


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Posts: 13166 | Location: Wyoming | Registered: January 10, 2008Reply With QuoteReport This Post
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any modern car doesn't care about ethanol at <10% with the correct octane. NO car engine cares about octane above the recommended level. BUT every other engine does care about ethanol. Don't feed your small engines ethanol in any form. Don't feed any older engine ethanol in any form. Don't store any engine with ethanol fuel.
I could go on for quite awhile.


“So in war, the way is to avoid what is strong, and strike at what is weak.”
 
Posts: 10974 | Registered: October 14, 2004Reply With QuoteReport This Post
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quote:
Originally posted by 2012BOSS302:
I'd use the 91 ethanol free, which is exactly what I use in my Mustang. If I actually needed a higher octane, I would mix in some race gas before I would put in an ethanol fuel. My truck on the other hand gets whatever is pumping.


Careful there, race gas can have lead in it
Bad for cats, real bad


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Posts: 1300 | Location: Idaho | Registered: July 07, 2010Reply With QuoteReport This Post
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