You can easily find this out yourself. Take your vehicle up a steep mountain pass on a hot day. If you’re driving at a very high altitude, there is less air to suck into the engine. Less air means the computer has to inject less fuel to maintain the proper air fuel ratio, so the car will not make as much power.

 

Quoting in black

Yes that's what I said, less power.
But no knock.

 

Don't forget to also put the transmission in "sport" mode. IMO that does more than the actual sport mode.

 

problem is you need more power to make it up a steep hill. Your car engine will lug. Low RPM driving, often referred to as "lugging" the engine, can actually damage your car over time (wear and tear is gradually increased). People often do this to save fuel, assuming that a car will use less fuel at low rpms. On the contrary, if you put the petal to the metal the engine will compensate for lugging your engine and will knock as its does not have enough power needed to accelerate under a higher load. The engine is starving for air. You should use higher octane fuel if you're living in the mountains unless you're OK with repairing your engine internals every 50,000 miles.

 

I do the same. I would never ruin my good equipment with ethanol gas.

I talked to a small engine repair guy years ago. He said ethanol ruins the carbs.

All my STIHL gear sits all winter long. Come spring, i can start it in 3 pulls or less. My experience is that is simply not possible with that crap ethanol gas.

I used to run ethanol free gas in my vehicles. They always performed better. However, in the end, it gets $$ for as much driving as I do. Further, with the track record of our ES's, I am just not worried about it.

 

if feel kind of stupid but until I read this thread I had no idea how much ethanol was in the fuel I was using. I’ve noticed better performance with mid grade than regular but that may be because at least in my jurisdiction (Ontario, Canada)
it seems that higher octane usually means less ethanol. The feds and province here have mandated a percentage of ethanol in all fuel that you will find at roadside stop, but from what
I am reading to meet the governments’ requirements the gas companies are putting higher levels of ethanol that required in regular. I may go for the highest octane now. I paid for the
damn car and chose the V6 for its performance and may as well get what I paid for.

 

Canada has its rules and regs.

In the US E10% has the same amount of Ethanol in 87,89 and 91 (some stations have E10% 94). The Ethanol is used to boost the octane rating for anti knock but all have essentially the same energy (BTUs/ per pound.

In my 21 ES 350 I have not experienced any gain in performance and MPG using above 87 except more cost $/gallon to fill up.

I have tried E free 87 with a performance and MPG gain due to greater BTU/pound over E10% 87.

E free fuel also has essentially the same BTU/pound across the various octane ratings.

In my race 2 cycle outboards all I use is 87 E free and they perform better than higher octane E free by the speed and lap time around the race course.

 

Ethanol ugh
Why use good farm land to grow gasoline?

 

I agree, a government subsidized fiasco like so many other things they do lacking good common sense

 

The farm lobby is strong in D.C. This is the sole reason it is used.

 

Not the sole reason.

Requirements mandating oxygenated gasoline, mandating a minimum oxygen content by weight, use ethanol as the oxygenating additive to meet the requirements. (MTBE used to be an alternative additive but has since been disallowed due to its environmental pollution hazard.) Those requirements have varied over the years, and even after the federal reformulated gasoline minimum oxygen content requirement was eliminated, some locations still have minimum oxygen content requirements necessitating adding ethanol as the oxygenating additive. (The minimum oxygen content requirement is to address ozone pollution in areas with a ozone pollution problem.)

In addition to that, there's also all the environmental groups demanding renewal fuels mandates.

 

You ever think that just maybe the environmental groups and the regulators are being paid by the farm lobby to promote ethanol?

 

Back to car talk, the Drive Mode "Sport" setting does not create more power from the engine
but does change the throttle response. Even in Drive Mode "ECO", if you floor the throttle,
you will get maximum power.

 

Thank you, mcomer. Your knowledge is always welcome here.

 

In NYS we have 2 different blends . Winter blend has additional butane to help cold weather combustion, but this also lowers mpg about 2% more than normal 10% ethanol.
The ES was designed for 87 and no benefit will come from higher octane. Higher octane only benefits cars with high compression ratios. The car will get more MPG with straight gas over 10% ethanol due to straight gas having more BTU's.
The part about knocking at altitude is false. VeroCarGuy is correct about making less horsepower due to thinner air, but wrong about the octane needs. Besides all modern cars having a knock sensor that automatically retards timing to prevent engine knock under all conditions, higher altitude actually needs less octane due to lower oxygen hence the reason they sell 85 octane in higher altitude areas like where my friend lives in Colorado. Turbos and other forced induction engines are a bit different, as they can stuff more air into the cylinders than normally aspirated engines at altitudes.
mcomer is on the money about horsepower in either of the 3 modes. The car will accelerate faster in sport due to changes in the engines rpm shift points in the transmission, but peak horsepower does not change.