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Difference in mpg from pump gas to e85?

Discussion in 'Terminator Talk' started by fivelitrecobra, Sep 12, 2019.

  1. fivelitrecobra

    fivelitrecobra Active Member Established Member

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    E85 is becoming more readily available in the area I live. Thinking about switching the car to a return style e85 system over the winter months. Not that I'm real concerned with fuel mileage, just curiosity...... to the guys that have made the switch, how big of a hit did your fuel economy take?
     
  2. Soap

    Soap Well-Known Member Established Member

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    You'll get roughly 30% worse fuel economy. So if you got 20 before now you'll get 14.

    --Joe
     
  3. Bdubbs

    Bdubbs u even lift bro? Established Member

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  4. 94slowbra1

    94slowbra1 Well-Known Member Established Member

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    If you can keep your foot out of it you'll be doing ok. I cant seem too, ha.
     
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  5. Skitzerman

    Skitzerman NE Philly Premium Member Established Member

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    Keeping your foot out of it, is like a big fat guy walking away from a chocolate cake. It ain't going to happen and ................

    1iox9y.jpg
     
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  6. blownstang4.6

    blownstang4.6 Active Member Established Member

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    On the street it'll be 20-30% worse. On the highway I haven't noticed much of a change, but I've only done one 95 mile highway trip so far and it burned 1/3 tank with the AC on. Today I'll be doing a 120 mile round trip to the track and a few passes. Have a littke more than 3/4 tank right now. Can report back over the weekend. Car is auto and returnless.
     
  7. c6zhombre

    c6zhombre E85 NutSwinger Established Member

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    It's 30% less when WOT. So, you beat on it....the needle goes left fast.

    Put on highway cruise 70mpg and leave it alone for some miles?....you will see much closer to pump gas mpg. Very close.
     
  8. oldstv

    oldstv Well-Known Member Premium Member Established Member

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    I live apx 4 miles from work, small gas tank in the mustang to start with and burn almost a 1/4 of a tank from the house to work and back with a trip to lunch added in.
     
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  9. slo984now

    slo984now AKA 01yellerCobra Established Member

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    A couple guys I know that cruised on E85 were surprised when the car did better on MPG than expected. Of course they weren't playing at all. They set the cruise control and left it.

    I've been curious about the engines built for E85. I remember talking to someone building a high compression 3V saying with the higher compression E85 would get similar MPG to gas. But that was at around 12:1 I believe. Granted at WOT it's still going to suck it down quickly.
     
  10. blownstang4.6

    blownstang4.6 Active Member Established Member

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    Updating as I promised above. 120 mile round trip and 2 track passes on Friday. 508rwhp auto Mach. Cruising 70-75 mph for 60 miles each way. About 250lbs of wheels and tools on the back seat and trunk that I transfered to my friends car at the track. Burned 3/4 tank of gas on E85.
     
  11. blownstang4.6

    blownstang4.6 Active Member Established Member

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    Something wrong there. All street driving stop and go 35-40mph speed limit it takes around 30 miles for my gauge to show 3/4 full.
     
  12. c6zhombre

    c6zhombre E85 NutSwinger Established Member

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    That's my kind of city driving! Ten miles doesn't sound like much.....unless that's 40 1/4 mile blasts street light to street light. LOL
     
  13. c6zhombre

    c6zhombre E85 NutSwinger Established Member

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    Higher compression plus ethanol is definitely advantageous. Doesn't take as much throttle input to get going......and also, doesn't take as much blower rpm/heat production to hit a target power number. So, definitely win-win for ethanol usage to be 12/1 versus 8.5/1

    The problem will be if you want to run pump gas. Then 12/1 is not very good at all. 10.5/1 seems to be a great compromise for those wanting to run both
     
  14. c6zhombre

    c6zhombre E85 NutSwinger Established Member

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    That sounds about right. But remember, 508rwhp fuel volume requirements are quite a bit lower than a 708rwhp fuel volume....so, power level matters to calculate fuel usage.
     
  15. blownstang4.6

    blownstang4.6 Active Member Established Member

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    Only at WOT though. Normal cruising shouldn't be much different. Agree?
     
  16. c6zhombre

    c6zhombre E85 NutSwinger Established Member

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    Agreed. Not much difference partial throttle, mainly WOT.
     
  17. 03' White Snake

    03' White Snake Well-Known Member Established Member

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    I get 120- 150 miles to a tank in my car on corn with mainly cruising and a few small hits.

    I have a built motor, cams, 10.4 CR and 21 psi of boost. The needle drops fast, but it is a toy so it doesn't matter much.
     

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