lilindy500 Posted June 23, 2008 Report Share Posted June 23, 2008 I got HP tuners and have been playing around with it. I turned on lean cruise mode from 55mph to 80mph. Now what percentage am I safe to cut it back? 10%? 20%? My AFR was set at 14.68 at all percentage of throttle input. Also my high octane fuel table and my low octane fuel tables are exactly the same. I imagine the high octane should have a higher timing than the low. Anyone have the stock high and low octane tables in hptuners for a 2003 silverado ss? Quote Link to comment Share on other sites More sharing options...
misterp Posted June 23, 2008 Report Share Posted June 23, 2008 The magic number is 15.2 to 15.3 to 1 in the 6-8 cells that the truck operates in during freeway/low-load cruise; you have to use a wideband to verify this, if you are too lean you loose efficiency (the truck has to open the throttle more to stay up to speed). - Mr. P. Quote Link to comment Share on other sites More sharing options...
lilindy500 Posted June 24, 2008 Author Report Share Posted June 24, 2008 I've been reading hptuner forums and the lean cruise won't work on my truck anyway cause it was from the states. They said you need a PCM out of a 04 GTO or something to have lean cruise work? Anyone know if its doable with my ss? Or do I have to jsut adjust the AFR? Quote Link to comment Share on other sites More sharing options...
misterp Posted June 24, 2008 Report Share Posted June 24, 2008 (edited) I've been reading hptuner forums and the lean cruise won't work on my truck anyway cause it was from the states. They said you need a PCM out of a 04 GTO or something to have lean cruise work? Anyone know if its doable with my ss? Or do I have to jsut adjust the AFR? Yes some of the PCMs did have an actual "lean cruise mode" programmed into them, which was deactivated in the US due to increased NOx emissions; just log which 6-8 cells of the fueling table the vehicle operates in during low-load cuise and change them to 15.2:1 - you might have to also adjust the power enrichment tables too... Mr. P. Edited June 24, 2008 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
lilindy500 Posted June 24, 2008 Author Report Share Posted June 24, 2008 lol that is WAY over my head haha. I will look into it tonight when I get home from work and try find out where to find those. Sorry I'm really stupid when it comes to this. I'd much rather be tuning snowmobiles. (you can tell i'm from the north) Quote Link to comment Share on other sites More sharing options...
SS_bnoon_SS Posted June 24, 2008 Report Share Posted June 24, 2008 (edited) There's also a "pseudo" lean cruise mode explained on HPT forums, basically changing the target voltage on the O2 in cruise mode/cells. I know it was worth a bit on my SSS. For the record, the lean cruise tables did nothing at all on my truck, so the OS is simply ignoring those tables. If you load an Aussie OS, then it can recognize the tables from what I've read. I too find it easier to tune a snowmobile, simply because I've been doing that longer. Edited June 24, 2008 by SS_bnoon_SS (see edit history) Quote Link to comment Share on other sites More sharing options...
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