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General Category => Cars, Bikes and more. => Topic started by: Steve O on October 20, 2018, 09:09:24 PM

Title: Flex Fuel
Post by: Steve O on October 20, 2018, 09:09:24 PM
My car is supposed to be able to run on flex fuel.  Recently, a local gas station has started selling it.  Has anyone tried it?  The gas is cheaper but it has more ethanol in it and the mpg is lower.  Is the trade off worth it?
Title: Re: Flex Fuel
Post by: k7 on October 21, 2018, 05:35:36 PM
i'd say no.

i can get gas with no ethanol added, it runs about $3.35 a gallon down my way. it's better than the 10% corn crap.

every car is different, though. the only way to know for your car, is run a full tank of 87, reset your trip meter, drive around, run it out, fill it up and with those gallons, you can calculate MPG (mileage driven divided by gallons at fill up). then repeat that, using E85. try to do the same driving, as in don't run highway on the e85 and compare it to stop-and-go city traffic when you're running the 87.

i calculate mileage if i modify air intake, or add an exhaust system, tune the ECU, things like that.


actually, check your car. you might be stuck running premium, or 93...that would suck.   :)
Title: Re: Flex Fuel
Post by: Mamushka on October 22, 2018, 09:11:22 AM
My car is supposed to be able to run on flex fuel.  Recently, a local gas station has started selling it.  Has anyone tried it?  The gas is cheaper but it has more ethanol in it and the mpg is lower.  Is the trade off worth it?

https://www.edmunds.com/fuel-economy/e85-vs-gasoline-comparison-test.html

If your asking if you will save money? No.

While the example above used a Tahoe for the test, results will generally be the same for most vehicles. Corn fuel contains a lot less energy per gallon so you need to burn allot more to get the same power output as gas.

From the test we also saw a bit less performance with corn and roughly the same carbon output.

If your goal is to spend more money, get much worse fuel mileage, have to fill your tank more often and output the same amount of carbon as gas, then yes, corn fuel is worth it  ;)


Edit:

For the same energy output as gas you will need to burn 39% more E85:
https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

On a side note, you need to burn a shitload more nitro-methane (240%) to get the same output as gas  :o
Title: Re: Flex Fuel
Post by: Steve O on October 22, 2018, 09:20:28 AM
https://www.edmunds.com/fuel-economy/e85-vs-gasoline-comparison-test.html

If your asking if you will save money? No.

While the example above used a Tahoe for the test, results will generally be the same for most vehicles. Corn fuel contains a lot less energy per gallon so you need to burn allot more to get the same power output as gas.

From the test we also saw a bit less performance with corn and roughly the same carbon output.

If your goal is to spend more money, get much worse fuel mileage, have to fill your tank more often and output the same amount of carbon as gas, then yes, corn fuel is worth it  ;)

lol  Yes,  i was wondering if it would save me money.  It sounds like flex fuel would not be good for the engine components either if the engine has to work harder. 
Title: Re: Flex Fuel
Post by: Mamushka on October 22, 2018, 11:04:50 AM
lol  Yes,  i was wondering if it would save me money.  It sounds like flex fuel would not be good for the engine components either if the engine has to work harder.

Not really working harder, just injecting more fuel to get (about) the same energy output.
Title: Re: Flex Fuel
Post by: GATLIN63 on October 24, 2018, 02:54:00 PM
I notice when I run it in the Titan and go back to high octane the engine runs a little wonky for a few seconds till the computer compensates for the different octane.
But for road trips E85 never the gas mileage sucks but some times around town I may through it in there. I heard E85 cleans the injector if it true or not I guess I will never know
unless I take them out.
Title: Re: Flex Fuel
Post by: k7 on October 24, 2018, 07:59:36 PM
i don't know about  modern engines, but ethanol gums up the fuel system in probably every vehicle made prior to 1998.

if someone told me e85 cleaned up anything in a fuel system, i wouldn't believe them. i think it's corrosive.
Title: Re: Flex Fuel
Post by: weeze on April 09, 2019, 10:53:43 AM
 I had to have the deck cut open and the inboard tank removed and a new tank, new glass job all because of ethanol.
 That stuff sucks and itll screw up anything you put it in. I have a Yamaha zuma that Im gonna have to devarnish AGAIN cuz of it. Theres a couple of non alchol places near me, there always are anywhere close to boat ramps, marinas, etc.
 long time ago, at the end of a race weekend at the Glen, I was super low on gas in my Spitfire and we put 3 gallons of race gas in it. That Spit never ran so good. Spitfire=it was the 70s.
Title: Re: Flex Fuel
Post by: JaxGator on April 09, 2019, 12:12:21 PM
I have a Tahoe that can run flexfuel E85, and I do use it. There is a noticeable drop in MPG when filling the entire tank with it, but if you mix it with 87 regular gas in a 50/50 or better favoring the 87 it gets about the same as far as I've noticed.  No noticeable drop in performance for me.  Totally non scientific analysis of course :)
Title: Re: Flex Fuel
Post by: k7 on April 09, 2019, 01:49:13 PM
sad thing, is e85 should cost $1.00 a gallon, for what you get compared to today's weak gas even.

i use real gas in my car that's 1988.

i use whatever in everything else, as long as it doesn't sit. ethanol sitting is like pouring sugar in your gas tank and expecting good results.

once i get my rx7 fixed, nothing but marine fuel. ;D
Title: Re: Flex Fuel
Post by: mcluvin on April 10, 2019, 09:18:11 AM
Don't do it.  When they switched to low sulfur diesel, it f'd with the seals on diesels that had been running high sulfur exclusively.  Lots of $1K injection pump failures from that.

I have read of tuned Civics getting crazy HP increases while running E85.
Title: Re: Flex Fuel
Post by: tktlwyr on May 01, 2019, 01:22:14 PM
I have read of tuned Civics getting crazy HP increases while running E85.

E85 runs cooler so you can run a lot more timing in it.  If I switched to E85 in my Shelby, I'd pick up approximately 70-80 rear wheel horsepower, but it's about a $3,000-$3,500 to switch to E85 capability.  Bigger injectors and pumps are required, along with new fuel lines.  Fuel economy drops sharply.

As for the regular E10 that we all pump daily now, it will gum up older vehicles/equipment since the rubber will deteriorate.