Any disadvantage to reducing lean cruise off-idle timer (B3635)?

[endo]

I've been running lean cruise for a couple weeks, don't really notice it engaging/disengaging but for looking at the display on the V2. Am running fairly conservative, i.e., max is 15.8.

I was just wondering if there is any reason not to reduce B3635, the off idle timer, down to something like 15-20 seconds? Noticed this post suggesting it should only be used for long term cruising, and thus the value should be set higher:


Set {B3634} to some reasonable warm-up time (600 seconds, maybe?), {B3635} to the off-idle "cruise time" you want as a delay (setting this too short greatly increases the likelihood of engagement when you are NOT really cruising long-haul), {B3636} as the speed above which you must be travelling for the trigger to occur (hint, set it fairly high) and {B3637} for a speed not too far below that (this is the "turn-off" trigger and you want to be able to drop below it without becoming a traffic nuisance.) I recommend setting {B3638} at 1.0 to start. "1.0" gives a nice little stair-step that's easy to spot in a dash chart.


Apparently the stock Holden tune is 150 seconds? I'm currently running 60, tempted to put it at 15.

[vzsv8]

Hi. My understanding is that the 150 seconds is to maks sure that lean cruise only operates on the highway. I have set mine down to 15 seconds on the basis that I want lean cruise to come in early, but not during acceleration, even if it is gentle.
AS a test I have set it down as far as 2 seconds for 'test purposes' with no driveability issues.
Also try reducing the speed at which it comes in to below your average cruise speed to make it as effective as possible.
Cheers, Steve

[Highlander]

Problem is... this system uses the Trims to actually achieve the correct lean cruise AFR. If you set the lean cruise too soon you will have absolutely no learning on the range which you want it to activate and thus will not achieve the correct AFR in the end.

[macca_779]

Problem is... this system uses the Trims to actually achieve the correct lean cruise AFR. If you set the lean cruise too soon you will have absolutely no learning on the range which you want it to activate and thus will not achieve the correct AFR in the end.

That is true but if you have an accurate airflow model to begin with as most of us no doubt do. Then that is of no concern. I don't bother with lean cruise as I just command my lean AFR's in B3647. That of course effectively gives me zero delay.