Here in AZ the cool air is leaving and my sensitive but meter say my sub is lacking some get up and go. Off idle to 4000 rpm stop and go traffic. The week it was in 100 degrees here I opted for premium. What a huge difference it made. Less throttle needed. Do any of you use premium during the summer months? Mind you, I am not talking about what is better or safe or needed, that's been beat to death. Jus talking if you notice a difference when you switch and IF you switch during the summer months.

 

most of the stations here switch the blends in the fuel for winter and summer...octane wise I personally have never noticed a difference but I rarely get anything other than 85

 

Isn't minimum octane 87?

 

The lower the octane, the more energy per gallon... If the engine isn't designed for it (a high compression/super charged engine) you will be reducing power...

 

depends on your location

 

There is also the murky question of whether or not premium fuel is 100% gas or not... Here is Texas I see the may contain up to 10% ethanol on the regular pump and on the mid-grade but I have not been able to get a cut and dry clear answer to does that mean premium is 100%.
From what I have gleaned from the web, the answer is maybe - maybe not.... it can depend on the state, the county and even the gas station....smh.....

 

Higher octane should allow for better or more agrrsive timing etc. Esp when its hot outside or climbing hills mountains etc.


initial timing etc would be affected too. I have yet o find anyone do a digital dyno session with hill climbs etc that would show that.


There is documented proof that higher oct gas give more HP.

 

Most, if not all, stations can tell you which grades, if any, are pure gas. A local station that had pure premium now has pure mid-grade also.

Some may recall my experiment a couple of years ago where I ran pure premium for several months and the mileage increase offset the price differential. But that worked because gas was pushing $4/gal. It doesn't work w/ $2/gal gas.

 

That's... not quite accurate. Higher Octane fuel does not have the ability to produce more horse power. Engine design can extract more power per gallon of a higher octane fuel...

"Many high-performance engines are designed to operate with a high maximum compression, and thus demand fuels of higher octane. A common misconception is that power output or fuel efficiency can be improved by burning fuel of higher octane than that specified by the engine manufacturer. The power output of an engine depends in part on the energy density of the fuel being burnt. Fuels of different octane ratings may have similar densities, but because switching to a higher octane fuel does not add more hydrocarbon content or oxygen, the engine cannot develop more power."

https://en.wikipedia.org/wiki/Octane_rating

 

not splitting hairs here. It does allow for more aggressive timing, fuel curves are changed and drivability changes.


For lack of a better word its should feel peppy'r as it does.