Question about E85?

[over2tonsofFun]

So if I build a motor to run E85. Do I have to exclusively run E85 all the time or can I run regular gasoline in it also. Like the new E85 vehicles can. Main reason I am asking is E85 isn't readily available in town. Closest is Cheyenne. plus if I do a road trip E85 also isn't readily available.

Tim

[His Royal Ghostliness]

You can run regular fuel in it. Why go for the E85 tho? I mean it's nice to be compatible with it so you can run it if need be, like for example how my diesels can run the B-fuel without developing leaks all over the place (they will actually run on just about anything that burns, including gasoline if mixed with something heavy enough), but is there any specific advantage the E85 in particular has over normal gasoline?

[turbo2256b]

If your interested in some fuel economy E85 dosent do well unless the engine is built to a point were it wouldnt be safe as a flex fuel vehicle. Other issues are different materials for pistons, rings, oils etc are required to hold up to its properties.

[gadget73]

Unless you have an ECM that can switch the program, you're going to be running one or the other. The Quarterhorse allows I think 4 tunes, so you could very easily have an E10 (everything has 10% now) and an E85 tune and manually switch. Of course it requires other considerations, but its definitely not impossible.

Modern stuff has a sensor somewhere in the mix that tells the computer to alter the tune, so its kind-of the same thing except you don't have to change the setting manually.

[GM_Guy]

flex fuel cvgms have no sensor. All done via timing, monitoring 02 and the engine behaviour. Which is done within the first couple of miles of filling up. And it will only do the check if it detects that fuel level has increased signicantly from when the engine was shut down (and some other parameters if you did an engine running fillup).
PDF available upon request.

Alex.

[gadget73]

so it still has sensors to tell the ECM that something is going on and it needs to alter the tuning. You just can't do that with an EEC-IV, it doesn't have the inputs or brain power to do that kind of thing.

[BigMerc96]

so it still has sensors to tell the ECM that something is going on and it needs to alter the tuning. You just can't do that with an EEC-IV, it doesn't have the inputs or brain power to do that kind of thing.

Kinda makes me wonder how the flex fuel EEC-V vehicles did it. They built FF 3.0l V6 and used them in Rangers and Taruii. The EEC-V system used in those doesn't have a lot more power than the later EEC-IV. They had a flex fuel module in them IIRC, but what it does and what other hardware it uses and how it interfaces with the ECU is info that I've never looked into.

[GM_Guy]

The pre2000 fords had a fuel sensor. Post 2000 did away with the fuel sensor, and use the exisiting sensors and programming to determine fuel type. Since I found the pdf, it's attached. And its really nothing more than monitoring air fuel ratio.

Alex.

[gadget73]

so are they running a wideband O2 sensor to get that range of AFR or is it still just the narrow band type ?

[knucklehead0202]

Even brand-new shit recommends not bouncing back-and-forth from e85 to gas regularly, but they do prefer you to put a lot of whatever you're running in it. Big-power nerds get excited about e85 because in theory you have more resistance to detonation. That said, you have to run WAYYYYY bigger injectors for it to actually produce and it's a much less efficient fuel so your mileage will suck shit. Unless you have a daily driven hot rod that needs it and a local supply that's cheap, e85 is a poor choice all around. There's a few places local to me that are a buck cheaper than regular gas, but when you factor in how lousy your mileage is, still doesn't compute. Forget it.