My car only recommends 10% ethanol but in Minnesota I tried mixing half E85 and half gasoline.

I didn't notice any difference accept a shorter tank.

- reading -----

I have put in a mix of up to 35% ethanol by adding some E85 to the E10.
Also in Minnesota... found E85 for $2.169.
That was part of the incentive, plus I was curious.

The car ran completely normal.

Pure gas, 65 miles per hour, winter condtions, = 30 MPG
E10, 65 MPH, winter conditions, = 27 MPG ( 10% drop )
E30, 65 MPH, winter conditions, = 27.5 MPG (8.33% drop )

I've done 1 tank of E35 and seems the same as E30.

No MIL lamps at 35%, or messages, and with a ScanGauge, all sensors look normal.

-John

While you -CAN- put in more than 10% ethanol fuel, DON'T DO IT! It will eventually damage the fuel system. It can damage the fuel tank bladder ($800 or so), the fuel injectors, the fuel pump, the fuel rails, and it WILL eventually confuse the ECU.

Motorweek did a Goss's Garage show on what GM changes in their "flex fuel" vehicles. The list includes:
Fuel filler neck and hoses, fuel pump assy, fuel lines, fuel type sensor (plugs into ECU), fuel rails, fuel injectors, engine head, ECU. They don't use a bladder in the fuel tank so they didn't have to change it.

Why'd he do this show? Because there are a lot of misinformed people who have been doing what you're doing, and it's costing them a lot of money when they have to have their car repaired!

Pearl is a
2007 Driftwood Pearl Prius
Package "B" (everything but leather, nav, and rear camera)

David, everything you said only applied to putting concentrated ethanol into a non FFV. ( IE E85, 85% ethanol )

Extensive reasearch and tests that grow in number every day is indicating concentrations of up to 50% ethanol are safe for any vehicle.

Cheers,
-John

I'll follow that up with any modern vehicle...

E85 is definatedly cheaper, but you do need to be careful. Hot Rod magazine had an article about it recently, where they ignored the econonmics and looked at it from a performance perspective. They were impressed with several aspects. First was the octane rating, which is typically around 105 octane. That is the equivent to true racing gas, which runs around $5-$6/gal. The second aspect they liked was that Alcohol runs cooler, making the air in the intake cooler, and hence more dense - leading to a better more powerful burn.

For our cars the higher octane is a real plus, since our engines have a higher compression (at least the HCH I does. I don't know about others). I have never figured out how I can run 87 octane in an engine with over a 10:1 compression ratio. The higher octane prevents knock and preignition, putting less wear on the valves. The down side is it has about 25% less energy, so you use more.

In Hot Rod's test they hooked up a crate engine and dyno'd it with regular gas and e85. They had to retune it for the e85, amoung other things including increaseing the fuel delivery by 25% (read decreasing fuel efficency). The e85 increase HP and torque. When they added a turbo charger the e85 significantly increased perfromance, mainly because they could not run the Turbo on regular gas.

So, for higher perfromance bang for the buck, e85 delivers. If you want economy (ie: MPG), not so much.

Sounds good Neil.

In my car, with gas, the HP meter reads 134 when I accelerate up a freeway on-ramp at 5000 RPM.

In my car, with 30% ethanol, my HP meter reads 134 @ 5000 rpm on the same ramp.

E30 is 35 cents a gallon cheaper, but it takes about 10% more of it.

I can't get E30 directly, so it is a hassle to mix my own.
But from an economic side, it's about a break even.
I'm hoping from an environmental perspective, it is a positive result.

I bought an FFV Ford Ranger in 2000 and it wasn't until just a few months ago that E85 has been available in my area. Maybe I'll try it out. I still would have to drive 20 miles out of my way to go to a station that sells it.

Meanwhile E10 has been mandated here.

Do what you like, but the engineers at Toyota have stated the max. % of ethanol the Prius will tolerate long term is 15%. If you use more you must know more than the Toyota engineers, right?

Lots of luck!

Pearl is a
2007 Driftwood Pearl Prius
Package "B" (everything but leather, nav, and rear camera)

It means you will assume all risks. The car may or may not work but if it fails due to a higher ethanol level, the repair cost is yours. If a trivial part fails, no problem, just substitute a higher ethanol part.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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