Anyone running something other than 87?

[jeansonne627]

I know I've read that the V6 was designed to be able to run on regular 87 unleaded but is the 87 the optimum fuel to be used? I read in the manual that it says 87 or higher so would putting a 91 or 93 perform better? Just put my first tank in and went with 87 to be safe

[Milk 1027]

87 will never be better than 91 or 93 depending on where you live.
Simple as that.

[jeansonne627]

just didn't know if was gonna be causing some computer problem like the ones the L99's are having with their first tank not being the right fuel

[Milk 1027]

That's because the dealer used 87 instead of 91 or 93.

If you use a higher octane from the beginning, you shouldn't have a problem.

[PieNsky]

It was designed to run on the lower octane and using the higher would not provide additional hp. The higher octane has to do with the controlled burn needed for higher compressions however the direct injection negates that need for its use.

[eckerj]

Have had the car for 7500 miles and put nothing
but 93 octane in it from the beginning. Last tank,
I filled up with 87 from BP.... Ended up getting
29.9 mpg for 472 miles. Quite the shocker..

[MontyCarlo]

In Iowa the cheapest gas is 89 octane with some added ethanol. That's what I've been using.

[FISHTAIL]

I'm glad someone has addressed this issue because I was wondering myself if there would be some hidden HP behind the higher octane fuel. I have 2,100 miles on my Camaro to date and all I've used is 87 octane from Chevron.

[FISHTAIL]

Wonder what the Cadillac guys recommend for the CTS on their manual. After all they run their engine with synthetic from factory maybe they recommend a higher octane as well.

[glambert1]

here is something interesting for yous I've known about this for years ,

32
commentsHigh Octane Gas Myth
by Jim Wang Print ShareThis

I know a lot of people who believe that higher octane gas is “better” for your car than lower octane gas, as if the words premium next to the higher ratings actually mean the gasoline is better for your car. It isn’t. If you believe it is, don’t be dismayed, you’ve simply become accustomed to reading the words “premium” next to the label and believing the great marketing machine that helped create over $10B in 4th quarter profits for companies like Exxon-Mobil. The octane rating of gasoline is a measure of how much you can compress the gasoline before it ignites, not how “good” it is.

Cars that require higher octane gas actually need that higher priced gas because the engines compress the fuel more before it ignites it. If you put regular gas in a car that requires premium, the gas will prematurely ignite when it’s being compressed and the engine will give you a knocking sound. This is bad for your car.

Chemists perk up…
For all you burgeoning chemists, gasoline is basically octane and heptane, or hydrocarbon chains that are 8 (octane) or 7 (heptane) carbons long. Octane simply can be compressed better (i.e. without the exploding part, at least at the same levels of pressure) than heptane. An octane rating of 87 means it’s 87% octane.

It’s a “rating”…
The reason why higher octane is more expensive is because it’s harder to refine the gasoline so that it contains more octane. Now let’s add another wrinkle… the octane is actually an octane rating, or it behaves as gasoline with that percentage octane would behave but might not actually have that much octane in it. While that doesn’t really matter, it does mean that the gasoline you use could have a mix of other things in it (still real gas though) to give it properties of a higher octane without actually having more octane

[squat]

I only run what is specified in the manual. Like others have said, the issue is with the PCM controlling the burn, higher than 87 wouldn't give me any extra benefit because my PCM is tuned for 87. Now if I were to get a tune for my car (if one ever came out) and was able to switch the timing then I would use different octane.

On a side note, it's interesting that octane is not the proper chemical term for the carbon chain. It's a pentane with 3 extra carbons and looks like this:




It's correct chemical name is 2,2,4 tri-methyl pentane. The 2/2/4 denote where the methyl groups are on the pentane chain. I suppose they call it octane because technically it still has 8 carbons, and octane rolls off the tongue better than 2,2,4 tri-methyl pentane.

[Susantroy1]

Originally Posted by squat

I only run what is specified in the manual. Like others have said, the issue is with the PCM controlling the burn, higher than 87 wouldn't give me any extra benefit because my PCM is tuned for 87. Now if I were to get a tune for my car (if one ever came out) and was able to switch the timing then I would use different octane.

On a side note, it's interesting that octane is not the proper chemical term for the carbon chain. It's a pentane with 3 extra carbons and looks like this:




It's correct chemical name is 2,2,4 tri-methyl pentane. The 2/2/4 denote where the methyl groups are on the pentane chain. I suppose they call it octane because technically it still has 8 carbons, and octane rolls off the tongue better than 2,2,4 tri-methyl pentane.

What the hell did you just say..... (way above this olé' motor head) all I know is Octane is simply a rating, nothing more nothing less, if you put higher octane in a motor designed for a lower rated fuel, that will produce less than optimum results adding carbon buildup in the valve-train due to unburnt fuel. also just the opposite in burning lower Grade octane to higher grade required engines..... pre detonation = loss of power and engine knock (fuel igniting to early in the compression stage)

[scrming]

but what if you are getting some spark knock with 87... spark knock sensors will pick up the knock before you can hear it in the cabin... so the ECU can end up pulling some timing before you hear it, reducing performance...

[Susantroy1]

Originally Posted by scrming

but what if you are getting some spark knock with 87... spark knock sensors will pick up the knock before you can hear it in the cabin... so the ECU can end up pulling some timing before you hear it, reducing performance...