Gas question: 85 or 89?

Try 85 first. If it knocks add 89 as soon as possible and use only 89 thereafter.

 

We drove thru Utah last summer on an extended trip with our 2006. I filled with 85 octane in Cedar City and drove to Cheyenne. No problems whatsoever. But, when we got to S. Dak., I decided not to use the ethanol blend fuel, even though it was only 15% ethanal.

 

When I was in Utah I used 85 in my 2006 Prius. It worked just fine.

Tom

 

what's the big deal with Toyota engine & using Premius gas ethanol like 93 or 91 ??
Why do you have to use the "lowest" one: 87 ????

I fuel all my Porsche's, MINI's with 93 + octane booster

 

Not Prius specific, but - -

I've never noticed a problem with 85 octane in any of my fuel injected cars, Prius or otherwise, in the areas where it is sold.

My two Detroit cars with carburetors both developed part throttle ping problems as they aged (which was much too fast) and needed 89 octane at sea level. But they were still happy with 85 in Montana.

 

Is this a real question, or just a joke? Assuming it's a real question, the answer is mostly one of money. Higher octane gas does nothing to boost performance but costs more. Generally it won't do any harm, unless the octane rating is way off.

I remember when the aviation industry stopped selling 80 octane av gas and we all had to switch to 100 Low Lead. It was not a good time for flying. You had to baby the throttle or the engine would cut out just when you needed it most.

Tom

 

If you are above 4500 feet, 85 Octane gas is fine.

 

Most modern engines have knock sensors which, in combination with the engine ECU, retard the timing if preignition is detected. This hurts performance and fuel economy somewhat but protects the engine. 85 octane should be fine but you may take a small hit on economy.

 

It may not be needed. But once you get used to it as I have. I stay with Premium.

Premium fuel is supposed to have less ethanol - even none added which leads to higher mpg. Driving in hilly terrain as we have around Puget Sound, Cascade mountains, Prius can accelerate with no hesitation. 60k miles later on my 2008, I lost my urge for a BMW 330.

 

85 octane is commonly sold at higher altitudes. It performs just like 87 does at lower altitudes, where you find 87 as the base level at stations. One cannot find 87 where I live @ 7,000 feet above sea level. Click and Clack have commented on this before.

Buying gas at a higher octane level than needed is throwing money in the street.

 

Premium has just as much alcohol as non-premium, unless you find and buy non-alcohol premium, which costs even more.

Alcohol actually raises octane in the fuel. Higher octane means only slower burning, important only if you have a high compression engine or one with deposits that cause ping.