V6 fuel switch 87 to a higher grade

[gghg]

Has anyone switched their V6 from the 87 octane to a higher octane? If so, have you seen any difference in performance and/or fuel economy? Over the summer I switched my Equinox to the mid grade fuel and noticed a performance difference especially when towing a trailer, seemed to manage the hills a littler easier and acceleration seems better. I just switched my Camaro 2Lt over to see if there is a bit of a gain.

[rtcat600man]

There was some write ups from "scrming" that indicated that the timing is pulled down while using 87 octane. He switched to 92 or 93 and there was no timing pull. This indicates that switching octane does allow you to use all the potential horsepower the V6 has to offer. Keep in mind that this engine will run fine on 87 octane but won't be fully utilized.

[PoorMansCamaro]

i never noticed a difference, but that's because my car has never tasted anything lower than 91 octane.

[John Shields]

I've run 87 and now strictly 91. I noticed no difference in either performance or MPG. I just like knowing that I'm putting better fuel into my car (the low grade stuff out here can be sketchy at best).

[justa25thTA]

how does octane ratings relate to fuel quality?

[h2oplay]

I switched to 92 or 93 after a couple of months and did notice a small change in mid-high rpm pull.

[gghg]

I was wondering if pulling the engine control fuses would make a difference, same sort of thing that some folks do when adding a CAI?

[usmc8411]

People saying they can feel the difference in 87 or 91 ocatane is in their head. You are not going to feel 5-6 hp....especially in a 3800lb car.

[E.T.]

It has been shown that timing is pulled with 87 octane. I'm actually curious as to whether midgrade is enough to avoid this?

[justmeron]

I wouldn't imagine any significant diff on hp

[h2oplay]

Originally Posted by usmc8411

People saying they can feel the difference in 87 or 91 ocatane is in their head. You are not going to feel 5-6 hp....especially in a 3800lb car.

You could be right, how did you arrive at the 5-6 HP?

Do you know how many degrees of timing get pulled using the lower octane?

what RPM range does it effect?

Don't know what dyno results would be on this motor, but my 550HP big block loses 40 with timing retarded only 4 deg.... it's not a linear loss, more than that and it falls off real fast....

[E.T.]

Found this at:
http://www.bikerenews.com/Stories_Ar.../Gas_Facts.htm

What octane does my vehicle need?
To determine your vehicle's octane requirement, look at the manufacturer's recommendation in your owner's manual. Most auto manufacturers recommend 87 octane gasoline, as measured by the (R + M) / 2 method on a test engine under defined operating conditions. If the vehicle knocks on the recommended grade, a higher octane grade should be selected. Some foreign vehicle manuals recommend a Research Octane Number (RON) instead of the more common octane rating that appears on most gasoline pumps. As a rule of thumb, the recommended octane rating can be determined by subtracting four (4) from the recommended RON number. A vehicle that calls for "91 RON" should use 87 octane gasoline (as measured by the (R + M) / 2 method). Using a higher grade than is required will not usually increase performance. However, if the vehicle is equipped with knock sensors, as many late model vehicles are, a higher octane grade may enhance performance.

Why does my vehicle require a higher octane gasoline than is recommended in my owner's manual?
There are two reasons. First, the engine may be at the upper end of the octane requirement range for the particular model. It may, therefore, knock during periods of heavy engine load. The octane requirement for each engine in vehicles of the same make is different because of variations in manufacturing tolerances. Industry testing has shown that this difference can range between two and five octane numbers. While you will not hear knock, the spark timing will be retarded, resulting in loss of power and performance.

[stand-al0ne]

I need to find the link here, but I remember reading dyno pulls on cars using 87 oct and getting 230-235 to the wheels and cars using 93 were getting 250 or so...

Ive only used 93 oct (the dealership filled my first tank with it) and until someone somehow proves that using 87 is better I'm not switching

[Gramps]

If you are not trying to shave ETs...then don't waste your time upgrading fuel. Save your money and buy a good CAI.