2-3 mpg increase?

[632 Regal]

filled up with midgrade instead of premium. Rebooted the computer and drove as usual. Instead of the normal 20-21mpg I have been getting 22-23 using the midgrade. weird stuff, no detonation or anything either... it's a keeper.

[winfred]

sweet http://members.cox.net/wdixon27/rockin.gif

[ryan roopnarine]

i would hope that you got higher gas mileage with midgrade. the n-heptane content raises the energy of the gasoline. if i'm ever doing a long trip (during the winter) in a car that uses premium, i'll bump down to midgrade and see what knocking occurs.

[repenttokyo]

i would hope that you got higher gas mileage with midgrade. the n-heptane content raises the energy of the gasoline. if i'm ever doing a long trip (during the winter) in a car that uses premium, i'll bump down to midgrade and see what knocking occurs.

don;t gasoline formulations change depending on what state / country you are in though?

[Dave M]

I haven't used anything but regular (89 octane) in the M50 non-vanos for years. No pinging, never, ever, not even once. Plus 30mpg on the highway.

Dave

[ryan roopnarine]

don;t gasoline formulations change depending on what state / country you are in though?


the 87% or 95(RON) number is going to be composed out of the same stuff, no matter where you go, generally speaking. the decrease of n-heptane (or increase of ethanol) to kill detonation is going to be the variable.

[winfred]

tried 87 in my chipped 535 on the last trip to va i did in it and mileage sucked aside from the bucket of washers falling down a flight of stairs when assing down on it, it lost 1-2 mpg over a few tanks at a steady 65-75 on cruise over a 2300 mile trip, never tried 89 ymmv


i would hope that you got higher gas mileage with midgrade. the n-heptane content raises the energy of the gasoline. if i'm ever doing a long trip (during the winter) in a car that uses premium, i'll bump down to midgrade and see what knocking occurs.

[ryan roopnarine]

tried 87 in my chipped 535 on the last trip to va i did in it and mileage sucked aside from the bucket of washers falling down a flight of stairs when assing down on it, it lost 1-2 mpg over a few tanks at a steady 65-75 on cruise over a 2300 mile trip, never tried 89 ymmv


i'm sure that the result is better in some motors than others, but the n-heptane number is what determines the bulk of the energy content of the gas. if it was 87% octane and 13% n-heptane the result would be different than if the gas was 87% octane and 13% ethanol or some other combination. i also don't have any real world data for what happens if more, rather than less, predetonates, like what might happen if you start varying the composition of the last 13%.

[632 Regal]

I think that I am chipped matters on the numbers too. I have like the only 530 auto chip mark produced and did notice the number change last year but attributed it to outside forces such as driving habits... went back to 93 octane. 89 octane did nothing but rattle til I rebooted the computer for the new fuel (1.5 miles later).


I haven't used anything but regular (89 octane) in the M50 non-vanos for years. No pinging, never, ever, not even once. Plus 30mpg on the highway.

Dave

[Russell]

Interesting. Mine has Mark's chip and have used 93 ever since about 2005. However, my peake tool indicated there is an issue with my by back (4,5,6) knock sensor. Sort of afraid to try lower octane.

[Desert Goat Herder]

I think that I am chipped matters on the numbers too. I have like the only 530 auto chip mark produced and did notice the number change last year but attributed it to outside forces such as driving habits... went back to 93 octane. 89 octane did nothing but rattle til I rebooted the computer for the new fuel (1.5 miles later).

I've got a 95 530i. What is this reboot on the computer? Is it just disconecting the battery for some length of time. I'm new to Bimmers so I don't know all the in's and out's of the beasts. BTW, I use 87 octane all the time and get 22.5 to 23 mpg average.

[632 Regal]

reboot the computer could mean disconnecting the battery for a while or disconnecting the wire harness from the ECU for a couple minutes. faster and you don't need to enter code into the radio.
I've got a 95 530i. What is this reboot on the computer? Is it just disconecting the battery for some length of time. I'm new to Bimmers so I don't know all the in's and out's of the beasts. BTW, I use 87 octane all the time and get 22.5 to 23 mpg average.