Using mainrate fuel for mileage comparaisions

[Redbowties88]

Well i rarely drive long enough without beating on my truck to get reasonably accurate mileage estimates on my different tunes. so im wondering if i log the main fuel rate at a set speed/location and then compare that to the same thing with different tunes active if that would give me a accurate reading of which tunes are burning the most/least fuel at a given speed?

 

[TrentNell]

Main rate ( MM3 ) is a hypothetical # it is not actually measured by the ECM , it just uses it for fueling reference.

 

[Redbowties88]

Main rate ( MM3 ) is a hypothetical # it is not actually measured by the ECM , it just uses it for fueling reference.

Oh ok...thanks trent. guess that gives me an excuse to take a trip somewhere so i can see the actual mileage then

 

[Dozerboy]

I tried making a few 60m. round trips in one day with different tunes refueling each time. It gave me a good idea what worked better, but it didn't seem to pan out as well on my next long trip.

 

[Redbowties88]

yea..well i know the DIC is worthless so i dont go by it but even though the readings are false when i run my new efi mileage tune the DIC now reads the same OR LESS then my old tune ACTUALLY got. when my old tune read in the neighborhood of 20-21ish i could get 18-19 about if its all highway or if im being very nice to it. (have gotten up to 21+)

now with the new efi tune my DIC doesn't get above 18mpg in the same conditions and it seems like im burning way more then i should even though i have been beating on it more then usual with efi it hasn't been that much more

 

[Drholliday]

Main rate ( MM3 ) is a hypothetical # it is not actually measured by the ECM , it just uses it for fueling reference.

It is a reference number, but if you set up your DSP with all the same fueling tables and say changed just the timing tables you could watch it to see what does use less fuel. If the tunes are the same with different timing then it would be a good way to judge when your moving in the right direction, IMO.

 

[Dozerboy]

I though about that, but finding a road flat enough is hard and you would have to do a custom pid of mm3 and pulse maybe fuel psi too. And I don't think it will pay off like I said my 60m round trip didn't pan out like it should in the real world.

 

[Redbowties88]

hmmmm...maybe ill check into it a bit and do some comparisons for the hell of it