Who uses a MPG tune for long trips?

[Rinkrat456]

I've been thinking....which isn't always a good thing...


Do any of you upload a special "fuel economy" tune before going on long drives? I'm curious what parameters you changed in the tune from your normal street tune, what MPG gains you saw and how it affected your driving.

If more than a few of you do this regularly, I've got a '96 GMC Sonoma with an iron block LS1 and 4L65 that I'd like to try a "fuel economy" tune on that gets uploaded before a long 3-4hour trip (which I make bi-weekly). My normal street/DD tune is adopted from an '02 Tahoe scaled up for the 5.7L. I get between 15-16mpg right now on 91octane and would like to see 19-20mpg (which would allow me to make the trip on one tank of gas vs filling up mid way down).

Any tips, suggestions or experiences to share?

[carlrx7]

ive played around with it a little,

made CFCO and DFCO more adgressive, and put car in open loop and removed 10% from the maf or ve tables under the cruise and idle areas.

engine would run around 16 afr or lambda 1.09, anything leaner and i could hear it ping. didn't mess with any timing.

no long term mesurments, but thats what i started with.

there are other ways i think, some mess with the o/l tables but i think they only make it richer, not leaner.

another method would be to run 87 octane and pull timing, but that goal only saves $$$ at the pump and reduces performance significantly. maybe you could try both?

some pcms have a lean cruise mode as well. mines a 4th gen pcm, just my 2cents.

-Carl

[Rinkrat456]

I've been reading a bunch about lean cruising lately. Apparently '04 GTO's that were brought over from Australia have the lean cruise option. Is there any way to use an '04 GTO pcm and use it to control my '00 (truck 5.3) 5.7L?

[jguev]

ive played around with it a little,

made CFCO and DFCO more adgressive, and put car in open loop and removed 10% from the maf or ve tables under the cruise and idle areas.

engine would run around 16 afr or lambda 1.09, anything leaner and i could hear it ping. didn't mess with any timing.

no long term mesurments, but thats what i started with.

there are other ways i think, some mess with the o/l tables but i think they only make it richer, not leaner.

another method would be to run 87 octane and pull timing, but that goal only saves $$$ at the pump and reduces performance significantly. maybe you could try both?

some pcms have a lean cruise mode as well. mines a 4th gen pcm, just my 2cents.

-Carl

i agree. run 87 and retard timing. change to earlier shifts to keep the rpm's down. makes sense to me but correct me if im wrong!