Flex-fuel engines.

[JB]

I am doing advanced research on my next car. . .sometime in the next year.

One of the vehicles that seems quite attractive (I have not driven one yet) is the Mercedes Benz C240 4Matic wagon (around 2005-2008) that has a flex fuel 2.6 liter V6.

They say it can burn gasoline or E-85.

I do know that the mpg, emissions and cost are lower for E-85 where you can get it.

Can you mix gas and E-85 in the tank, or do you have to select one or the other and stick with it?

Can it use 87 octane or does it require premium when it uses gas.

Is there a noticeable difference in performance between gas and E-85?

With only 185HP in a 3400lb vehicle is it a slug or is it peppy (I consider my Forester marginal with 165HP)

Anyone currently using a flex fuel vehicle??

 

[rbh]

Re: Flex-fuel engines.

Years back we used a flex fuel type pick up.
It was either gasoline or propane, you flipped a switch to go from one to another.
One of the issues was that the engines timing had to be electronicly modified as the two fuel had different burn curves (changed the advance curve)
As for the gasoline to the E-85 probably something in the same ballpark.

 

[rockyrude]

Re: Flex-fuel engines.

I believe most flex-fuel vehicles have a single tank so mixing has to be allowed. I know GM's computer handles the octane change and adjusts the engine accordingly. Yes, e-85 gives lower performance and economy, not sure where the "break-even" is $2.00 a gallon cheaper and 5 mpg less. That's kind of why I haven't jumped on one yet.

 

[drrpm]

Re: Flex-fuel engines.

The flex fuel vehicles are built to handle up to 85% ethanol. They will run on regular gas as well. It doesn't seem like E85 is particularly useful since its not readily available in large parts of the country and even if you can get it the cost/mpg ratio is not good.

 

[emilsr]

Re: Flex-fuel engines.

I've got an Impala I use for work and it's flex fuel. Gas and go....either E85 or regular....can't really tell any difference except it gets 25% better fuel economy running on regular.

As for the Benz, wifey's 320 calls for premium fuel but all the Benz mechanics say it will run on anything. I'm a big fan of MB products but have heard a few horror stories about the 240.....so FWIW do your homework on that one.

 

[ufm82]

Re: Flex-fuel engines.

I saw some of E85 stations while on my 3300 mile saga trip out west two weeks ago. Typical difference in cost was about 20%. That's about the difference in fuel mileage so why bother? It's definitely not everywhere. Sure, it adds to the "smug" factor but it ain't the fuel of the future! LOL

UFM82

 

[stackz]

Re: Flex-fuel engines.

The flex fuel vehicles are built to handle up to 85% ethanol. They will run on regular gas as well. It doesn't seem like E85 is particularly useful since its not readily available in large parts of the country and even if you can get it the cost/mpg ratio is not good.

about the only thing I can add to this thread is that here at work one of our new GOV cars is a hybrid ford fusion (gas/electric). its got 1900-ish miles on the clock and thats it.

its in the shop right now having the injectors replaced (I believe direct injection injectors?) as one of my coworkers apparently didnt put in the "flex fuel" gas-ahol as there are now apparently flex fuel specific pumps? either way, car would not run right and the dealership techs said it was because the wrong gas was put in and it "burned hotter" than flex fuel would due to less alcohol being in it and burned the tips of the injectors as they stick into the cylinders for direct injection engines...

kinda weird and out there but thats what I heard today when i went to take out the car for work and it wasnt in our lot lol.

 

[QC]

Re: Flex-fuel engines.

the dealership techs said it was because the wrong gas was put in and it "burned hotter" than flex fuel would due to less alcohol being in it and burned the tips of the injectors as they stick into the cylinders for direct injection engines...

kinda weird and out there but thats what I heard today when i went to take out the car for work and it wasnt in our lot lol.

Is this car labeled as FlexFuel? That explanation does not seem right unless there is actually something wrong with the injectors pr programming. From E85 to 100% gasoline, FlexFuel vehicles should compensate and operate properly no mater what the mix in the tanks is. That doesn't mean you couldn't get "bad" gas of any ratio, but "wrong" doesn't make sense to me.

 

[stackz]

Re: Flex-fuel engines.

Is this car labeled as FlexFuel? That explanation does not seem right unless there is actually something wrong with the injectors pr programming. From E85 to 100% gasoline, FlexFuel vehicles should compensate and operate properly no mater what the mix in the tanks is. That doesn't mean you couldn't get "bad" gas of any ratio, but "wrong" doesn't make sense to me.

I'll have to wait until we get the car back to confirm that for you. but I feel the same way. there's no way there's enough "specific" gas stations around to justify selling a vehicle like this. I liken it to trying to sell a plutonium powered car to the masses when there's only one station in the state you can fill up at, for all we know the dealership is blowing smoke up my coworkers butt and/or he is just relaying the info wrong as I know he can barely change a tire as it is.

 

[j_martin]

Re: Flex-fuel engines.

If you look in the owners manual of most flex-fuel cars, it will tell of increased maintenance requirements, especially oil changes, when using E-85.

I was involved in the home grown fuel alcohol cult of the early 80's. We'd burn it right out of the still, with a little denaturant added (ATF required) and a little bean oil for lubricity.

Had fun tearing the tires off the car. When you set up the engine to use the extreme octane available (130), it'll make HP like you wouldn't believe. Because of the extreme performance and a little thing called water vapor phase change from the 10% water in it, the mileage was almost what you'd get on gasoline. The engine would not burn straight pump gas without putting the heads through the hood. It definitely was not "flex fuel"

Modern E85 is 105 octane. That tells me that the mixed HC component is pretty poor. When you set up an engine to run that, or gas, you're going to have to trade off something.

What's traded off is mileage when running alcohol.

There are some serious mechanical issues with ethanol, like affinity for water, corrosive, and combustion chemistry that's downright scary. When an engine is built to take that, it'll run well and long on good old gasoline.

 

[snake77]

Re: Flex-fuel engines.

Is this car labeled as FlexFuel? That explanation does not seem right unless there is actually something wrong with the injectors pr programming. From E85 to 100% gasoline, FlexFuel vehicles should compensate and operate properly no mater what the mix in the tanks is. That doesn't mean you couldn't get "bad" gas of any ratio, but "wrong" doesn't make sense to me.

I'm inclined to agree here. I am a jaguar /Land rover tech and we have also started using direct injection and are have the same problems as being clogged or burnt out. Engineers tried to tell us wrong fuel but I believe it is a programming issues. I don't care what fuel where using but to clog an injector that is working at 2175psi then just doesn't seem plausible.

Forgot to add. when I started in this field I graduated the Mercedes Benz Elite program out of U.T.I. and I have to say I am now Jag, Landrover, Dodge, ASE master L1 and of all the cars worked on the mercedes benz is among the top of the line. E85 can be added but it is best to try and run your tank down as low as possible before changing fuel
type the computers do all the changes required but it is best to run out the fuel.

 

[Sprky]

Re: Flex-fuel engines.

. the mileage was almost what you'd get on gasoline.

I thought it took roughly twice as much alcohol as gas to attain the same BTU's?

What mods did you make to the carb to flow that much fuel?