Premium fuel + E85?

Why would you put $17.00 of Premium gas in the tank? It is not better gas. It contains no additional cleaning agents. The only thing that Premium contains that Regular does not, is additional "anti-knock" compound. This keeps high performance / high compression engines from pre-igniting and "knocking." While I appreciate what you are attempting to accomplish, save your money for something else.

Ethanol? I don't know that it cleans your engine any better than Regular gas either.

 

Why?

 

If you have changed oil regularly, there is no crud to knock out in that engine. Put in 87 octane and drive it.

 

Ethanol does burn cleaner than non-ethyl alcohol containing gasoline. I doubt it actually cleans the engine, but it may have a minor effect. As you are in the US, I'm told your fuel already has about 10% ethyl alcohol in it, so you are wasting your time mixing up a cocktail for the car. Unless you just want more alcohol in the fuel.

According to your owners manual you can use gasoline containing up to 15% ethyl alcohol. Putting in too much E85 will get you above that. Whether that will cause problems or not is debatable (and there is much debate on that even on this site). I like to believe the Toyota engineers in these matters.

 

Yeah I actually think the manual says no premium fuel for the prius, but to use 87. on my Mini CooperS (BMW) it says the MINIMUM fuel to use is 91premium, so I think you are safe with the cheapie gas. We have never put prem in our other prius.

 

Use 87 octane E10 regularly and the engine will be plenty clean.

 

What about seafoam engine / fuel treatment? If there were any dirty fuel injectors or sludge buildup in the engine seafoam might help. But it's really intended for high milage engines and I'm new to the prius, I don't know how that would effect the bladder in the tank or the internal sensors. Has anyone tried seafoam in their prius?

 

My main concern would be the fact that both premium and E85 have very high octane ratings compared to what the Prius is designed for. E85 is typically thought to have an approxmate octane rating of 116. Mixed 50% with premium gas, with an octane rating of 93 inexact math gives you a combined 104 rating. As the octane rating is a measure of how hard it is to combust the fuel mixture, and the Prius is designed for 87, I would not do it for concern that the engine is not designed for fuel that is so hard to ignite.

 

On a related subject, out here in Idaho, at 5000+ ft elevation, we have 85 octane (not E85) fuel as well as 87 octane to choose from. I have been running the 85 since it is meant to improve performance at higher altitudes, and also because I've read that lower octane fuels actually contain more energy per gallon than higher octane, but they burn faster in normal engines, resulting in less efficiency, something which the prius' engine cycle eliminates. Is this true? Or should I change back to the less expensive 87 octane gasoline?

 

The Prius fuel filter is located within the fuel tank, so if the filter was clogged you would have to replace the fuel tank.

Unless you seek to make trouble for yourself, I suggest that you stay with Toyota's recommendation and use only 87-octane name-brand gasoline.

 

This is madness.

Stop putting premium in a Prius. Do not put E85 in a Prius, it is not designed to run on it. Don't do it.

OK, ignore the advice to the contrary. Put it in. While you're it, why not brush your teeth with mr clean. If it's good for a floor it must be good for your mouth, right?

 

Cmon now.
That guy at O'Reilly must know what he is talking about. More so than the folks at stupid Toyota.

 

It's not only a fuel filter.
You have to replace the entire fuel line parts with E85 certified ones.
Toyota engine is designed for only up to 10% of ethanol (E10).

Ken@Japan