So I've been seeing alot of the newer GM's trucks and such out with the "flexfuel" logo on them and I was wondering what the difference was. What did they do differently to handle the use of ethanol? Theres a lot of stations around in Colorado that offer it and there are more popping up every day. Also, what could I do, if anything, to my 4.3 to turn it into a diy flexfuel? Thanks

 

#1 - E85 requires a AFR of 9.76:1 where gasoline is 14.7:1 You will need more ethanol at peak efficiency which will require 50% larger injectors. Larger injectors are not available for the 4.3L unless you were to go with a completely custom fuel injection setup.

#2 - Lets say you get the injectors upgraded. Next, you have to update the PCM to allow it to maintain the new AFR appropriate for E85 and this would typically require the installation of a wide band O2 sensor as most narrow band O2 sensors can only read down to 10.5:1 AFR. Also, the spark tables would need to be modified to further increase the efficiency of the engine with the higher octane mix.

#3 - Then comes the materials used in the fuel system... You have to make sure that all of the elastomers will not degrade in the high ethanol concentration.

To get the most out of it, the compression ratio should be increased or some type of forced induction utilized.

Now, there will be a *bunch of stuff* that will be stated by others. What I challenge EVERYONE to do is cite sources for your statements.

Here is a website with quite a few people that have made the conversion: E85Vehicles.com

*EDIT* Another place that I have been reading through is E85Forum.com

 

and here is the kicker, my truck is flexfuel, and it said the gas mileage range with E85 would be 40 to 60 miles less on a full tank than regular gas!! but its good for the enviornment

 

Until they can figure a way to use ethanol that gives the same power output and mpg as gasoline does, I say "pffttt". It's more usefulin the form of the plants it comes from.

 

Yes the range may be shorter resulting in worse gas mileage but the fuel being burnt is easier on the enviroment, since it burns cleaner and does not use much cude oil, as 85 % of it is ethanol which is corn alcohol.

 

Not all ethanol is produced using corn...

And yes, the mileage will be lower when using ethanol in a conventional engine at this point in time because the engines are designed for gasoline. If designed for ethanol, you wouldn't see a drop. The IndyCar racing league is a great example. They switched to 100% ethanol this season and with engines specifically designed around the fuel.

 

Sounds um, complicated. Theres no way I have the wherewithall to undertake a project like this but if I wanted to just use E85 every once in a while would it damage the engine at all?

 

Just yoink the engine, computer, and fuel system from a 5.3L Flexfuel engine, and you'll be good to go, lol

 

Why would you want to? Your vehicle will gain nothing from it except a certain degree of cleaning and there are products made just for that purpose. Will it damage your engine, probably so, and the occassional use won't make a drop in the ocean toward helping the planet.

 

Ahhh more wishful thinkning I guess...