How does octane 89 affect an engine when you normally use octane 87?

1. 0

   scrambleposted 13 years ago

   How does octane 89 affect an engine when you normally use octane 87?
   
   I normally use regular (87) octane but occasionally it is the same price for the 89. Should I take advantage or should I keep using the regular?

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2. 60

   cellconcreteposted 13 years ago

   You won't feel any difference between 87 and 89 and neither will your car's engine even though the gas station and your car's manufacturer would like you to believe otherwise.

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3. 67

   ptosisposted 13 years ago

   If live in the Colorado Rockie Mountains, where the altitude is above 8,000 feet then the highest octane the gas stations  will sell is below 85 octane.
   
   At sea level ca by 92 octane. But with the crappy ethanol - that stuff acts like you have water in your gas.
   
   I had a 87 Honda Rebel and the state is trying to kill me by using ethanol - I had to put in octane booster AND gas dryer in it for every fill up.  Or else I wouldn've died ten times over because when hit the gas to pull into traffic or go faster on the on ramp to the highway - The ethanol KILL the engine - and me along with it.
   
   I hate ethanol..... Makes food prices higher, and takes more fuel to make it than it's supposed to save......... And deadly on a 1987 Honda Rebel 250cc.

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4. 60

   Just A. Guyposted 13 years ago

   It seemed that no one commented on the effects on your engine...the difference between octanes has to do with the ability of the pistons to compress the within the cylinders. A higher octane needs less pressure in order to become explosive enough to push the piston up (generating power in the engine). The pistons will come down to a set point and then the spark plug will fire and that point is dependent upon the recommended gas. It will compress more (or go lower) for low octanes and compress less (or stay higher) for higher octanes. What happens when you put 89 in and 87 suggested car is the gas becomes super compressed since the piston will still go to the same point - thus creating undue stress on the engine and in extreme situations, can lead to the cracking of the pistons and their seals. Oppositely, if you put 87 in an 89 engine, you will get carbon buildup as the piston does not compress all the gas and leaves some remaining after it fires. Though not significant in either situation, this is what happens.

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5. 71

   gijayposted 13 years ago

   your engine will burn "slightly" hotter and you'll get "slightly" better gas millage.  But the difference is almost not noticeable when you factor in the price difference in the gas.
   
   I wouldn't stress over the difference...

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