Monch

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that is not correct, it is a very common mistake to think so. You shouldnot think of it as "premium" as it is no better than "regular." the only difference is a small amount of extrahydrocarbons - "Octanes" - which cause the gas to burn a bit SLOWER than regular unleaded. Its less volatile and therefore better suited to higher compression engines where ignition may take place before the spark because of high temperature/pressure - thats how diesel's work and its not what you want in a gasoline engine.</P>


the oil companies do not want you to know whats going on, it costs them $0.01 / gallon more to make, if even that, but they call it "premium" and alot of people buy it thinking it is a superior gasoline.</P>


I spent 6 years working as an analytical chemist, i know what I'm talking about. Do your own research if you disagree. </P>

Mach 1 Boy

I am not disagreeing, but if what you say is true, the difference between running 91 or 87 should not be too noticable, correct?</P>


My guage cluster says "premium unleaded fuel only" and I am not going to run anything less then 91 if I don't have to (unless gas prices go WAY up..Which they could! <IMG src=smileys/smiley11.gif border="0">).</P>

Monch

on your car it will make a difference, on my GT it willhardly benoticeable. you need to run premium - you have a high compression engine and your ignition system is setup to burn 91+ octane fuel. on the majority of production cars on the road - it will not make a difference. </P>


I'm not saying that one should never use premium - it exists for a reason - engines like yours. But, if your owners manual had said 87 then you would not gain any benefit until you did something that could take advantage of the fuel. for most people that is bumping the timing / getting a chip / or slapping on new heads or pistons which change the compression ratio.</P>


enjoy your car - i've ran against a few mach 1's out here - i'm envious - but i'm into modding.....</P>

Guest

Listen to what Monch is saying. lol that's all I gotta say. He's not pulling this out of his ***. </P>


Cars with 9.5:1 compression and higher need at least 91 octane gas, or "premium".Anything else can use 87 "regular." Of course if you have a car running 12:1 compression, you're gonna need like 101 octane race gas...which is rather expensive, but attainable,if i'm not mistaken. <IMG src=smileys/smiley3.gif border="0"></P>

GSXRIntensity

It's all about the compression Mach 1 Boy<IMG src=smileys/smiley2.gif border="0">. My 02 GT's ownersmanual recommended 87, and that is what i put in it now...that is until I get my dynotuned Ford Chip<IMG src=smileys/smiley16.gif border="0">. Premium will only help you if it's recommded for engines such as yours. If your read my VERY 1ST post on this thread, you'll see what I said about the premium performance in my car.</P>

2kpony

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EXCELLENT POINT OF VIEWS <IMG src=smileys/smiley16.gif border="0"></P>

millatime

your best bet would be to run what ford says is best for your car. They suggest 87 because if you go much higher it causes detonation and that can be very harmful to your car