Ok, to anyone. I have a 97' with a 4.6 with 147,000. I thought about adding a power chip. However, it says to put the 93 octane fuel. Now, the book, says NO to the higher octane fuel, so what is the do;s, the don;ts, good idea, bad idea.

I just need to know what;s the deal. Anyone who can give me some info on this I will be greatful.

Thanks

 

Hi bmc25,

This is a commonly asked question, and an important one..........

Your owners manual will tell you to use only 87 octane fuel because that is what the engine is specifically tuned for from the factory - these modern fuel-injected & computer controlled engines are tuned for specific octane levels, usually 87 octane unless it's a "performance" application. And when you are running on the stock factory tuning/powertrain program in these trucks & SUV's, that is what you should do, run 87 octane, so your owners manual is correct.

That changes when you use a *performance* program - the Superchips tuning specifically retunes the engine for the use of premium gasoline (91 thru 94 octane), to deliver more horsepower & torque - so when you're using the Superchips tuning you need to use premium gas, just like when you're on the factory program you need to run 87 octane - it's a matter of what the engine is *tuned* for, in other words.

The reason for this is due primarily to the difference in effective burn rates - lower octane gas ignites quicker in the combustion chamber, where higher octane fuel takes longer to ignite - thus you have to initiate the spark *sooner* when using higher octane fuel, so it has enough time to burn completely in these modern fuel injected engines.

For example, using premium gas on the factory program can give you a result ranging anywhere from no noticeable symptoms to having driveability problems and even getting "Check Engine" lights - because the higher octane fuel may not have time to fully burn on the stock factory tune.

So it all boils down to a simple matter of using the octane level that the engine is tuned for, basically.