jkim0507

I've been reading up recently on how ethanol free gas is better for your car and how it gives you more mileage than gas with ethanol in it. A lot of the discussions I have found discuss 93 Premium VS 91 Ethanol.

I pass two gas stations on my way to work everyday and stopped by the other day to put in Ethanol free gas. I was disappointed to find both gas stations only carry 87 Ethanol free gas and the closest gas station with 91 Ethanol free or higher is much too far away.
I drive about 500 miles a week and want to put in what's best for my MDX. The price is about the same and both are QT gas stations. Anybody an expert on this?

thisaznboi88

iTrader: (7)

Stick with 91. It's for the compression ratio. Less chance of detonation

neo1738

Agreed higher compression engines have more pressure. More pressure means less heat required to detonate the gas. This is why higher octane is needed. That is the rating at which gas explodes. Technically the 91 or 93 is able to withstand that extra pressure before detonating. While ethanol free may be better for your engine the octane rating is still the same.

losiglow

iTrader: (1)

Agreed. The EtOH free may get you more power and mileage since gasoline contains more chemical energy than ethanol. However, the octane is the same and may result in some spark knock if your engine is especially hot or you push it hard. Ironically, pulling timing due to this will decrease power and mileage which would probably put you right back where you were before with 10% ethanol fuel.

jkim0507

Thank you for the great feedback. 87 is the only Ethanol free octane rating available near me so I will stick with 93 Premium. Thanks again!

kurtatx

Go with what's recommended by the manufacturer.