Questions and Answers

Proper Fuel For A T-Bird Q. Vincent, Hi, my name is Michael and I own a 1995 Ford Thunderbird LX. It has a 4.6 litre V-8 engine. I was wondering what gas I should use? I am currently putting in Premium Gas because someone told me all V-8's should use premium.

Today my Father told me that I am wrong and that the car would run the same on regular. Then about 20 minutes ago my friend who is a "car-aholic" says to use the middle gas because premium is for larger engines. What gas should I use and why?

My second question is about my car's performance. Is there anyway I can find the performance specifications for my car? I heard there are web sites that when you put in your VIN number they give you exact specifications. Is this true? Do you know of any sites?

Thank you very much,
Michael

A. There is a lot of debate over what gas should be used with what engines and with that a lot of "right" answers. The gas that should be used is the one the manufacturer recommends be used. This information can be found in the owners or service manual that came with your car.

In general there is nothing wrong with using a higher octane fuel that then what is recommended, but there are times when this can actually be harmful. The octane rating refers to the volatility of the fuel and if an engine is designed to use 87 octane and you put in 93 octane, it may develop pre-ignition or pinging. Since the 93 octane is more volatile, it will ignite quicker. If the detonation sensor detects this and retards the ignition timing, you will get lower performance and lower MPG. Chances are the only sign this is happening is, over time, you'll notice the drop in milage.

So using 93 octane could lower your engines efficiency instead of rasing it. An 89 octane fuel could be a decent compromise between the two fuels but you still could have the same results as using the 93 to a lesser degree.

Additional Information provided courtesy of ALLDATA