BlackGMC

iTrader: (31)

I finally got around to doing some tuning... I applied the lean cruise patch, pretty easy to do, but it required a full write, no biggie. I have it set up to go 16.00 (0.08)in the really light cruising loads, which is basically all the cells in the 50-75 mph range with the cruise control on. The edges are 15.5ish(0.04)... When the lean cruise turned on, it was seemless, no exhaust tone changes, no lunging, to nothing. If i did not have my wideband i would not have know at all...

if you look at the logs the Commanded AFR goes to 16 and the wideband follows, the trims stay the same. I forgot to log to log the O2 sensors to see if they are still switching, but i am pretty sure they are cause the Wideband AFR still fluctuates just like it does at 14.68.

Anyways hear are some screen shots and logs.

blazinblue

iTrader: (15)

looks good commanded afr right with the WB. I got to get my wot afr dialed in before trying lean cruise, im slow let us know how you mpg goes.

BlackGMC

iTrader: (31)

I can try put i only drive the truck like 50 miles a week at most... But DC_Justin sent me a link to a MPG pid that i am going to try tomorrow!

kbracing96

iTrader: (26)

Is that the "scary things lurk in here" patch or just the latest update?

hirdlej

iTrader: (31)

You should be able to go to 17:1 without problems shouldn't you?

dewmanshu

iTrader: (4)

yeah but I would bet 17:1 isn't a place of efficiency. You will start to find where the ratio will drop power and cause you (or cruise) to give more tps to keep up the speed. I am not talking alot, but just enough to make the mpg go the other way. I could run 17:1 but it never seemed to get me anything. 16.5ish seemed to be the best eeerrrrr the limit to seeing a positive difference in mpg.

kbracing96

iTrader: (26)

I did a little testing with my truck while driving across the salt flats one time (REALLY long, flat, straight highway) and found that with my heavy, brick shaped truck that 16-17 was to much. It cut power back enough that there wasn't any gain in fuel mileage. 15.5 seemed to give the best balance of economy and enough power to still push the truck though the air. Now a lightweight car with good air shape like a Fbody, you could probable get away with a 16-16.5, cuz you don't need as much power to push it though the air.

BlackGMC

iTrader: (31)

Yep is it...

Honestly I don't know what is a good AFR, i am trying 15.5-16.0 for now...

thanks for the tips.

GMCtrk

iTrader: (27)

probably not a good idea to do this without a WB, correct? Where do I get the update?

MikeGyver

iTrader: (5)

I would like to see before and after scans of a 14.7 cruise and a 15.5 or whatever cruise under controlled conditions. It seems to me like you would have to open throttle more at any level of lean.