Hey guys, New here, first mustang ever.. so bare with me please. Ive also tried searching for an answer and was not successful, so excuse me if this has already been asked. Im from California, I was wondering whether i should be using 87, 89, or 91 for fuel. I heard that if you use higher octain, you have a bigger chance of frying certain gaskets? Im sorry if this is a stupid question. Either way, if someone could help, id appreciate it.

Car Specs
Black ext. //Red int.
05' GT
Bone stock.

 

87

 

You are not going to fry any gaskets using a higher octaine fuel. You will however get better performance out of your vehicle

 

I have a C/L Air Induction Kit with Brenspeed tune and the only difference I felt in the High Octane tune was more umph in the higher speeds other than that they were about the same. When I was stock there wasn't any difference. Thats my opinion though.

 

ok cool, im using 89 at the moment. so its not gonna void my waranty if i put like 91? Example: my brother has an audi TT S-Line 3.2 Quattro, if he uses anything other than 91, and it causes any harm (exsessive pinging, etc etc) it can potentially void his waranty.

-Thetics

 

As per the owner's manual, you should be using 87 octane gas. You shouldnt get any gains from using a higher octane fuel by itself. As far as I know, the octane rating doesn't have anything to do with the "potency" of the fuel itself, it just tells you how much pressure the fuel can withstand before it spontaneously combusts (if you are an engine, this is a bad thing for you.) Higher octane fuels can handle more compression.

So, you can put a tune in the car that gets you more performance and uses higher octane gas, but that extra HP isn't coming from the high octane fuel, it comes from an increased compression ratio in the engine. Your brother's Audi has a turbo, so he MUST use high octane because the turbo increases compression.

Someone who knows what they're talking about tell me if that makes sense.

 

THETICS - DO NOT PUT 87 OCTANE IN YOUR CAR!

Most of the people responding to your question DO NOT LIVE IN CALIFORNIA! Our gas sucks here because of all the additives the state puts in for our ridiculous emmisions requirements. Most other states 87 is equal to between our 89 & 91. You won't hurt your car using 89 but might ping if you tune your car and start doing any performance mods. We don't have 93 octane in california and 91 is our premium. (if you want to call it premium) You don't need to worry about 'frying' anything no matter what octane. If you ever use Race Fuel, then you'll have have to make some adjustments but that will be regarding your cats and 02 sensors.

 

Yeah, I don't know nothin' about no California gas.

 

IT SUCKS! We have the most ridiculous emmision laws and our gas has 103 more additives than any other state.

[IMG]local://upfiles/24802/F250E47C7144461494B60399578B3D06.jpg[/IMG]

 

Then why is SoCal so notorious as a street race scene? Or is that all B.S.