E85 and the 2008

No, because the high-octane ethanol is blended with low-octane hydrocarbons to yield the desired final octane shown on the gas pump (87 or whatever).

 

Not wanting to stand on anyones toes here,but with the folks i deal with [in US]they tell me it rated at 105,here in Ireland it's 104 octane.

 

E85 means 85% ethanol.

And ethanol is an OK additive (as the previous poster pointed out it is a good substitute for MTBE) at no more than 10%. It's really a huge step sideways, otherwise. And if you run E85 in any vehicle not designed for it, you will screw up something expensive eventually.

 

E85 ish great shtuff!

I like mine with an olive, and a twist of lime - shaken, not shtirred!

*hiccup*

 

Here in Albuquerque NM, we've been under mandate to have the stations pumping oxygenated fuel in the winter months as a pollution abatement measure for many years. That used to mean either MTBE or ethanol added, for about four months. MTBE went away a few years ago, so it has just been added ethanol lately.

But a few months ago the local papers carried a story that nearly all the local supply was converting to E10 even though it was late spring going on to summer because the interaction of the regulations and incentives made that best for them. The old stickers on the fuel pumps warning of ethanol content in the winter months were generally modified, either by slicing off the date range with a razor blade, or just crossing it out.

To nudge the thread drift back a little closer to the original E85 topic, I've had a personal experience with a car not liking alcohol content higher than originally contemplated in the design. I bought a 1975 BMW 2002 new. By the time I sold it in 1987 I always ran with windows open, as the cabin always smelled of gasoline. I had inadvertently bought gasoline at an off-brand station which sold gasoline with alcohol content (assume E10 level) for some years. I believe that some components in the cars fuel system were incompatible enough that they eventually cracked creating a very low-grade leak.

It can take time for the full compatibility problems of a major change to manifest themselves. I don't think most of the 1940s generation of automobile engine designers fully realized that they were relying on the lubricant properties of the tetraethyl lead then most commonly used to boost octane to keep wear of valve seats and valves to an acceptable level.

I'd need an awfully compelling advantage to consider converting operation of the car to a fuel expressly designated as not acceptable by Toyota.

I consider the total impact of the use of corn-derived ethanol in US motorfuel to be strongly negative, so for me E85 in our Prius starts with a compelling disadvantage.

 

Need to specify the measurement method for that number to mean more. The two methods which have been most commonly around for decades are Motor Method (ASTM d 357) and Research Method (ASTM d 908). As the Research method gives the higher number, for a long time retail gasoline sale advertising in the USA displayed it. Some government genius decided to split the difference, and require that retail advertising display the average of the two numbers, which is sometimes termed an AKI number.

My impression is that retail fuel in the UK is labelled with the RON number, what is the custom in Ireland?

 

I'm still waiting for someone to try to explain why we even care if the "octane rating" is above 87. The engine is designed to run on 87 rated fuel. Anything much higher -should- result in poorer mileage. Those who panic relax, at high altitudes 85 rated fuel is just as good.

The reason is complex, but a simple way to look at it is that a way to rate fuel was needed, as the engines of the time "needed" more power, and the engineers were bumping up the compression ratio to get more.

Octane was chosen as a "test fuel". It burns more slowly than the majority of the hydrocarbons in gasoline and also resists detonation better. It is run in a "test engine" and then the "fuel under test" is also run in that test engine. The difference in detonation resistance is then computed for the test fuel, hence it's an "octane rating".

Now, if you put "high octane" fuel in an engine designed for low octane fuel, it will not complete burning and will be exhausted to the cat still burning, where the excess unburned hydrocarbons will be taken care of. This is lost energy.

I will say that the Prius engine, being a long stroke "Atkinson" style design, may be less prone to loosing the energy, as it gives the fuel a long time to burn.

At any rate, you don't need high octane fuel, you don't want to pay for high octane fuel, and usually, you will get slightly lower mileage with high octane fuel in an engine designed for low octane fuel.

 

Well stated, David, and completely correct.

Tom

 

It gets more complex still. I'm breaking up my "response" to two messages so I don't completely loose people.

You WILL get lower mileage with fuel that has ethyl alcohol added. The reason is ethyl alcohol has less energy in it than gasoline. The comparison is:
Ethanol - 21.1 Mj/litre
Gasoline - 32 Mj/litre
I'm not going to redo the calculations, I'll leave that as an exercise for the reader (I love to say that, after all those years in school ). At any rate, with E10, it should result in about a 3% drop in mileage. With E85 it's much greater! It had better be very cheap fuel!
One more reason to NOT use E85.

Now, don't jump to the conclusion -I- don't like "ethanol". I love E10. It burns much cleaner than straight gasoline. It takes care of any water that gets into the fuel system (fuel line antifreeze not needed!). But the part that I like the most is the car smells like an alcohol burner when you first start it up, before the cat warms. Brings back happy memories of early chemistry experiments.

 

i now of a company in the Netherlands thats providing a E85 KIT for the prius
it works great BUT there are a lot of smal letters you need to be aware of
like change off : fuel lines, fuel pump damage, fuel filter replacement faster then normal and more things like that
there are already priuses here that use E85 with this kit

 

And you yourself, do you have a kit?

[I'll be in Amsterdam in September,was there last November,A BLAST!
Going again just to remind ourselves what a great time we had!!]

 

i am not using it.. there are a lot of things you have to take care off using E85
like replacing your fuel filter half as fast.
and fuel lines maybe need to be replaced AND the fuel pomp may break.
and i engine that have lighter material you maybe need to put in a additive