Has anyone been tuning for gas milage?

[smeshey]

Just wondering is anyone has been tuning for gas milage? Any ideas where to start would be. Not to worried about it on my Z28, but now that i have a truck too. I am thinking of trying to get better MPG out of it that 17 city. Any suggestions would be greatly appreciated. Thanks Scott

[luv2spd]

17 mpg city is already really good. Before my cam, when I was tuning for my longtubes I seemed to gain almost 2-3 mpg from tuning. All I did was get the fuel trims correct and advanced the timing quite a bit in the low load areas like when cruising.

[Wo0111]

haven't really targeted fuel milage during tuning but I keep track of it
when going on long cruises-just curious I guess my on the open
road around 70-75 in 6th gear gets 27mpg--last run down to Bakersfield
calif. to play at fomoso speedway chasing screamn03 down I-5 average
100 mph the 01 used about 1/2 tank of gas-we live in east sf bay area
so to bakers field its a bit of a ride and at that speed I calculated aprox
22mpg.---screamn03 cobra does not do that while with fuel but is quit
capable of kicking my butt ;D

[rattle]

Could get even better mileage if the HPtuner gods would let us enable lean cruise mode

[txhorns281]

Could get even better mileage if the HPtuner gods would let us enable lean cruise mode

agreed, what about tuning in open loop for leaner than stoich AFR? It might not stay perfect at let's say 15.5 AFR but it will still be leaner than stoich and save gas mileage. I wonder what kind of driveability issues will ensue with running that lean... :P Specially for us cammers, it'd be sooooo nice to get improved gas mileage.

[rattle]

lean cruise mode is the only really safe way to do it, with this mode enleanment only occurs under very light load conditions. Still kinda waiting for something from Keith, Ken or Chris on why we cant enable it. While back they said not legal, but I cant see how its more illegal than enabling full open loop operation or ability to disable cat monitor o2 sensors.

[txhorns281]

lean cruise mode is the only really safe way to do it, with this mode enleanment only occurs under very light load conditions. Still kinda waiting for something from Keith, Ken or Chris on why we cant enable it. While back they said not legal, but I cant see how its more illegal than enabling full open loop operation or ability to disable cat monitor o2 sensors.

well you could command the OLFA table at low rpms and low MAP (cruise conditions) to 15.xx AFR. You could then use the PE vs RPM table to enable at 0 TPS and command stoich at idle, do the lean cruise thing, and also use to PE to richen up at higher load (higher MAP values via TPS thresholds) and in higher rpms (above 4K). If the VE is well tuned then it'll look something like this maybe:

https://webspace.utexas.edu/wl333/Lean.jpg

this should work right? since PE mode supercedes any other operation once enable thresholds are met? thoughts? :P

[JimMueller]

Has any one tried Txhorn's idea?

[12secSS]

lean cruise mode is the only really safe way to do it, with this mode enleanment only occurs under very light load conditions. Still kinda waiting for something from Keith, Ken or Chris on why we cant enable it. While back they said not legal, but I cant see how its more illegal than enabling full open loop operation or ability to disable cat monitor o2 sensors.

All the paramemters that can currently be modified by all the tuning solutions (HPTuners, LS1-Edit, EFI-Live, HPP3, etc.) are made to increase the performance of your vehicle for "supposedly" off-highway use. If any tuning solutions offered the option to tune the lean cruise, it obviously would not be for off-highway/performance driving usage ... therefore it would require a CARB EO#, which would jack up the price more. Lean cruise is specifically for emissions, and modifing it to run leaner would increase your emissions. I forget which, but either HC or NOX would be increased, which would be a direct emissions violation without proper approval. So you want Ken, Keith and Chris to put the (legal) lifes (and business) at stake for a measly little MPGs, I don't think so. Enabling lean cruise would require some research on the legallities prior to allowing the general public to mess around with specific emissions controls.

[MNR-0]

The difference between lean cruise and a well tuned and fuelling vehicle is minimal. If you can't get lean cruise enabled, just jack up a few degrees of timing at cruise.

[87gmc]

If memory serves me right efilive had where you can enable lean cruise mode

[03Quadrado]

Question... I've got VCM suite for my '03 Silverado and it seems that the Lean Cruise section is intact and if I enabled it my truck would lean out according to the values i input. My Q is this: Is it that other versions (or other applications) of Vcm suite dont have a Lean Cruise section or is it that no one knows the correct values to use to make that section work? Im very interested in and am considering experimenting with this section soon. I've got a 6.0 liter LQ4 and I might get 14mpg on the highway with a stiff tailwind. I'd like to see maybe 3mpg better if possible. I've already increased the timing down low and it has helped a little. Also this: DFCO is a great way to get better mileage in town because of all the frequent stops. (Decelerations). :P