How will using a mix of gasoline and 15% ethanol affect my '09 Ram 1500?
Jack

 

As I understand it, it won't be long the 10% in the gas will go up to 15%.

 

Mileage slightly lower, thats about it

 

Does the octane rating decrease with the additional ethanol? The 5.7 Hemi suggests 89 but allows 87. What happens if the octane falls below 87?

 

Ethanol increases octane, not reduces it.

 

Ethanol increases octane yes, but it burns differently.

Compared to gas, it does not contain the same amount of energy. Thus requiring more to get the same effect.

Little experiment if you want to call it that- Go find a gas station in your area that offers 100% ethanol FREE gas. Do a complete fill up and drive like you normally would. Then, use a 10% blended Ethanol gas and drive the same way.

With me and everyone else who has looked at it, our MPG's rose when using gas with NO ethanol in it.

"But it's cheaper!" That may be, but if you calculate it out, you might find that it is also costing you more in the long run compared to a fuel with no ethanol in it.

 

I've read a lot of gas vs e85.
And mpg vs price, gas ends up winning vs e85 due to the mpg drop.

 

Generally E85 has to be about 25% cheaper than E10 to break even on the milage and about 30% cheaper than pure gas (which we havn't had in MN for many years)

Around here is it usually closer to a 20% spread between E10 and E85

 

What if I increased my ethanol blended gas to 91? Will the higher octane give me more energy?
Jim

 

I think you need to do some reading and understand what octane is.