E10 - E30

Discussion in 'Mazda' started by rweatherford, Apr 7, 2008.

  1. rweatherford

    rweatherford Times my Mileage by Six

    I will be trying to do some experiments with variable rating my E10 and E85 percentages when filling up my car.

    A recent study showed my engine in a Ford to get the best mileage at E30.

    I filled up this weekend and added 1.5 gallons of E85 to my E10 fuel which resulted in an E17 mix. (17% Ethanol) So far I did not see a reduction in FE during a trip to St. Louis. I am using the ScanGauge to monitor the long term fuel trims. The LTFT went from -4 running E10 to 0 running E17. This is the "base" fuel trim in the PCM, so everything is right on what the PCM thinks it should be.

    Here are the numbers.

    Trip south was into a full headwind with flags flying straight out. I drove 60-65 MPH. Pulled down a 31.5 MPG trip with 2 adults, 3 kids and a stop for lunch. Rolling hills on 4-lane most of the trip.

    The return trip had a tail wind. Drove 60 MPH for most of the trip and pulled in a 34.5 MPG segment with no stops. I found on the last few miles that if you could drive 50 MPH you might pull out a 40 MPG average.
  2. rweatherford

    rweatherford Times my Mileage by Six

    Finally finished this tank of E17. Total miles 340. Total fuel 11 gallons.

    30.9 MPG on E17. That is our best tank ever. Long term fuel trim was at 0-1.

    Refilled with mixture to make E27. We'll see how that does.
  3. aca2983

    aca2983 Well-Known Member

    Interesting. Keep us updated.
  4. psyshack

    psyshack He who posts articles

    I haven't seen a diff. with booze fuel....
  5. rweatherford

    rweatherford Times my Mileage by Six

    Missouri no longer sells regular gasoline, so I can't compare a NON E10 tank. I don't really agree with forcing people to use something, but many members here believe in things like that, just that most don't like corn based ethanol.
  6. rweatherford

    rweatherford Times my Mileage by Six

    Yet another tank in the books. E27 made the LTF trim go to +3. Mileage was 27.1 MPG. There were more city trips this time. Longer trip segments seemed to not be effected.

    Took a 150 mile trip today and had 35.5 on the way and over 36 MPG on the way home. This was E28. LTF trim showed +4.
  7. rweatherford

    rweatherford Times my Mileage by Six

    E28 tank. 30.2 MPG. I made an E29 mix tonight and upped tire pressure to 50 PSI.

    If fuel keeps going up I will switch back to E10 only as E85 is up to $2.95 and I have E10 contracted at $3.09. I guess that would be a decent A-B-A test.
  8. rweatherford

    rweatherford Times my Mileage by Six

    E29 tank = 30.2 MPG. Mixed up an E29 tank tonight and set tire pressure to 50 PSI.

    If fuel prices keep going up I will switch back to E10 only. E85 is up to $2.95 and I have E10 contracted for $3.09. I guess that would make a decent A-B-A test.

    I forgot to look at my LTFT but I would guess it is about the same.
  9. rweatherford

    rweatherford Times my Mileage by Six

    Back to E10. My contracted E10 fuel is now cheaper than E85. According to the scanguage there is a 6% correction factor for running E30 vs E10. I figured with current prices you would only save 4.2% in $$ by mixing an E30 mix. The price difference between E10 and E85 is currently 17%.

    Last trip was 32 MPG. Not quite a typical tank. I'll let the next tank go like normal.
  10. Klauven

    Klauven Active Member

    Pretty neat, its too bad Mazda 3s can't use E85.
  11. rweatherford

    rweatherford Times my Mileage by Six

    Mazda5 can't either. I was mixing my own E30 by adding a little E85 and then the rest with E10. It's not a recommended fuel mixture in the owners manual.

    Basically one gallon of E85 to 3 gallons E10 = E30.
  12. Klauven

    Klauven Active Member

    Don't you run risk of damaging the engine? I heard Ethanol is more corrosive so the engine must be designed to handle it. Also, I thought E10 yields worse FE than 100% gas, so how is that E30 would increase FE?
  13. ma and pa

    ma and pa Active Member

    Well it has finally happened here in VT most stations have E10 so my last three fillups have been E10 and I was expecting a negative hit on FE but to my suprise We got the best 3 tank average of the year. 29.119 mpg vs 28.600 for the 3 previous fills on straight gas. In fact I could find only one or two 3 tank averages that were better an then only by a tenth of a mpg. That was in '06 on different tires that were supposed to be high RR compared to the tires I use now as selected per a magazine article. Still have'nt resolved that one yet. It has warmed up so cold starts eased up but and my wife (ma) found a slightly better departure time for her morning commute but overall for our CR-V it seems that E10 will be OK in the MPG area. Jonathan (pa)
  14. BillyK

    BillyK Active Member

    I just got better fuel efficiency with an e25 mixture (36.2mpg) than with straight gas (35.1mpg) on my 05 Escape Hybrid. As for E30 besting E10 in mieage, see this link:

    as for ethanol and engine damage: this link reveals an unmodified Prius has used E85 for 60,000 miles and is in superior condition than one run on straight gasoline:


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