Mileage on 87 octane

Discussion in 'Fiesta ST Chat and Discussion' started by rw02kr43, Sep 27, 2013.

  1. rw02kr43

    rw02kr43 New Member

    I saw yesterday that running low octane will rob you about 20hp. How does it effect mileage?

  2. Register or Sign in

    Advertisement Sponsor

  3. Removed

    Removed Guest

    One of the SVT overview videos with Tim mentioned slightly worse mileage on 87. Not sure by how much.
  4. Smokin

    Smokin Active Member

    Yeah, I tried going low octane on my GTI last winter for money-sake and the mileage was worse per dollar than using 91 octane.....
  5. wash

    wash Active Member

    The miles aren't as fun.
  6. Sil3nt611

    Sil3nt611 Active Member

    If you drive it to use all the HP your gas mileage isn't going to be great either. Might as well have fun while not getting good gas mileage than be robbed of HP with a lower octane and not get good gas mileage. :)
  7. spangenb

    spangenb Active Member

    I am here in the snow belt and will be driving my FiST year round. I have 185/60-15 snow tires on it now and couldn't use all the power anyway. I decided to swap my ECU program for the Cobb economy tune (~6psi boost) at the same time I swap my snow tires on. I am also going to run 87 octane til the summer wheels go back on. I expect to average 30mpg+ in combined driving with that setup. Might as well save money in the dead of winter so I can subsidize my 20-25mpg summer :)

    Sent from my iPad using Tapatalk
    RodMoe likes this.
  8. RodMoe

    RodMoe Well-Known Member

    Let us know how that tune is working I have been thinking of doing the same thing
  9. spangenb

    spangenb Active Member

    So far I have had the tune in for a couple of weeks. I would guess the car has about 140 HP with that tune. It feels like it has about the same go as my '12 Focus. I don't know for sure but the throttle tip-in seems slower which is good for economy too. I drive mostly county 2-lane roads and I have 120 miles at the 3/4 tank mark. So far I would say it's a great tune for winter or even long trips.

    Sent from my SCH-I545 using Tapatalk
  10. spangenb

    spangenb Active Member

    Just filled up. Temperature has averaged 30F here for the last couple of weeks and I suppose we may be on winter blend gas now in my area. Adding in the 1% difference for the snow tire diameter, I averaged 31.6 mpg. That is 80% two-lane county roads and the other 20% split between highway and in town. I have been trying to shift with the shift arrow with occasional runs up higher in the revs when needed. Again this is with the Cobb economy tune and 87 octane gas. If I can continue to average this in combined driving then I will be one happy camper :)
    Firesail likes this.
  11. stuntdoogie

    stuntdoogie Active Member

    I cant ever see me use anything less than 93....unless gas here hits $5 a gallon....praying i never does.

    Sent from my SPH-D710 using Tapatalk
    Mr UFO likes this.

Share This Page