I've filled the HAH with 1/3 ethanol by volume now (6.7gal E85).

I expect to see a 10% hit in mpg. But I'm more curious to see how VCM reacts- will the car sense more power and go into eco mode sooner or more often? Or will there be some confusion and eco mode will be twitchier?

I don't think there will be much if any perceptible change- 1/3 ethanol isn't all that much of a change- probably effectively about 94 octane. I'm not willing to go with straight E85 at this point.

I picked a poor time of year to do this, though- shifting to winter blend, rapid temp changes, all make for several variables at play that can cloud my results.

Yep. 7.5% decrease in mpg this morning. I've been using CC for a few days as baseline to remove any influence of my foot- 40.7, 41.5, 41.2. This morning with same temp & traffic conditions I got 37.5.

I think ECO mode is a little twitchier, but I can't yet tell.

Cold idle sounded a tad rougher, but it might have been in my head.

What made you decide to do this experiment? Have you tried it in your previous cars or been reading about others who have used it to increase octane ratings?

2005 Accord Hybrid 15.65@89.91mph

2003 Lancer Evolution VIII (Sold) 287whp/283tq

Wow you are brave. Not too many people want to turn their car into guinea pig these days. Keep us posted

2005 Accord Hybrid
2005 Durango HEMI (wife's wheels)
1998 AUDI A8 4.2Q

Mostly because I can. There's a pump on my way home from work and it looked lonely. I've become fascinated with the idea of E85.

Without touching off further debate about domestic-produced fuel, net energy/emissions balance, subsidies, and the corn/cellulose issues, I wanted to see for myself what booze would do in my vehicles- how the particularly complex controls of the vtec/vcm Honda engine would react. I wanted to be able to speak from experience- I think ethanol has a bright future; the existing sources/systems may be suboptimal but its a start- both to returning to domestic energy and reducing greenhouse emissions.

I doubt I'll keep the HAH on this mix- I might push to 50% for a bit, note the effects, then return to regular gas. But at least I'll know for myself.

I might keep the Exploder on this diet, though, since it is a disproportionally higher emitter. Tough call, since that is mostly used for short runs, so the benefit may get lost.

Not much guinea pigging going on, really. E10 is a fact of life in many areas, and I'm not all that far off of it. But I know what you mean- these vehicles are significant investments that we depend on for day to day life- not a good idea to play with too much fire. I know just enough about what I'm doing to be a threat to those around me

I would have been shocked if I did notice a problem. Even straight E85 shouldn't hurt in the short term (possibly not long term, either- lots of variables and not lots of outside studies on it). C-H bonds is C-H bonds- an ICE will burn 'em all, electronics and efficiencies notwithstanding.

Hi GoNavy:

___One of the problems w/ E85 is that the FFV makers cannot design the engine around it. Given the high octane, they could be running closer to 12.5:1 vs. 10:1 before pre-detonation. Since gasoline is the prevalent fuel, that is not going to happen. I do have to wonder how much of the FE hit you could get back while running an E85/100 designed ICE at 12.5:1 instead of an E10 designed ICE at 10:1 on E85?

___Good Luck

___Wayne R. Gerdes

Exactly. FFV is by definition a compromise...which implies that it suits neither regime optimally.

I'm sure someone somewhere has built an ethanol ICE from the ground up and has numbers. Sounds like something a MechE dept at a university would do.

Drag racers use a similiar fuel, methanol, with good results at outrageous boost levels. The engines are built for alcohol based fuels from the start, with extremely high compression (if you include the blower's boost).
But they aren't too concerned with fuel mileage

Regards,

yeah, I should've said a 'normal' engine

Hasn't F1 used Methanol for decades? IRL too?

F1 has very stringent fuel consumption requirements...no surprise that when Honda entered the scene in the mid-80s with McLaren and Williams, then Benetton, they cleaned up immediately.