Driveability VS Lopey Cam Idle ? - (TUNE, LOG & DETAILS ATTACHED)

[Boost]

I will try to post as much info as I can, to help you advise me. And as always thank you very much in advance.
Engine in question is a stock bottom end 2002 5.3 "Z" motor (factory original flex fuel) with the following cam specs:

220 222 0.570? 0.570? 112(+2)

with some good Texas Speed PRC heads and all supporting mods (full exhaust etc.)

It is known for a decently aggressive idle and has loped in the past, however since clearing some stumbles, stalls, and hiccups out of it with simple tuning changes the idle is of course higher and the lope is gone. It's kind of cool that the cam is "hidden" and still makes good power but honestly I prefer both (smooth street manners and nasty idle as well). On both of my other reasonably similar builds I did not have the lope disappear this much just by adding idle speed, IAC, and timing. One had a way bigger cam and still chopped hard at a perky 850ish idle, the other has similar cam specs and I was able to lower the idle to a very low 670 RPM (for a mean rumble) and still runs smooth off idle and at most times once reasonably warm.

I would be fine with either a low or high idle as long as the distinct cam sound returns with no negative effects. Here is the exact current tune as well as a log of just cruising lightly with that tune yesterday.

33 deg next RACE TUNE.hpt

sunday 1.hpl
sunday 2.hpl

(note: wideband is reading in AFR sorry vehicle is on ethanol as can be seen in the alcohol PID. Working on this issue, gauge DOES read in Lambda but haven't found the transform yet. Fueling is mostly ok though, about .85 WOT and .95 idle / 1.05 Part Throttle).

edit: do I need to post some Config file, or can you guys see the Parameters I was logging? Just to be sure.

[Boost]

http://www.masterenginetuner.com/ls-big-cam-idle.html

[kevin87turbot]

If you want a more choppy idle, you can make three changes that will help.

1. Lower the idle speed. You might try 800-825 rpm instead of 890 rpm.

2. Lower the ignition timing at idle. Target around 21-22 degrees instead of 28 degrees.

3. Change the over/under speed timing tables to stock, or even a couple degrees higher than stock.

[kingtal0n]

You'll also want to run open loop a/f ratios of roughly 15:1 to 15.5:1

Heres my tiny cam 5.3
https://www.youtube.com/watch?v=FhqWjsASX5k&t=6s


It smooths out and sounds stock at richer af ratios but like you, I feel a nasty idle is more fun

[Boost]

If you want a more choppy idle, you can make three changes that will help.

1. Lower the idle speed. You might try 800-825 rpm instead of 890 rpm.

2. Lower the ignition timing at idle. Target around 21-22 degrees instead of 28 degrees.

3. Change the over/under speed timing tables to stock, or even a couple degrees higher than stock.

You'll also want to run open loop a/f ratios of roughly 15:1 to 15.5:1

Heres my tiny cam 5.3
https://www.youtube.com/watch?v=FhqWjsASX5k&t=6s


It smooths out and sounds stock at richer af ratios but like you, I feel a nasty idle is more fun

Thank you both, kevin87turbot and kingtal0n for your replies. Everything you said I found to be true in my previous "tinkerings", and will apply those exact changes to an experimental idle tune to be tested this weekend by the latest. The goal is to retain drivability with zero stalls or stumbles to speak of, I will again log and maybe even record some idle clips or at least describe the difference. Here is what I will try so far, hopefully all the changes take effect without multipliers and other stuff interfering.

33 deg next RACE TUNE Xperi-Mental lope idle.hpt

As I've been thinking about this trying to figure it out on my own before reading your replies this morning, I realize that both cars we have "sound good" when they are seemingly hunting for idle timing at lower numbers as well (like around 16ish?). It may be that the 5.3 is was adding timing for underspeed and the 6.0 is pulling it for overspeed (it still sounds good and is at 670 RPM with no major driving concerns) but RPM and timing is fluctuating on both when the desired lope is there. Keep in mind the stock throttle on the 6.0 is bigger (90mm and fly by wire and drilled) so maybe that's why I had to smooth out the 5.3 more? In any case focused on the 5.3 right now to make sure it never stalls any more on decel after a pass or low speed maneuvers. I feel like initially I had to sacrifice the lope with bandaid fixes to accomplish that as I'm still learning what I'm doing.

[Boost]

An update if it helps anyone, I finally figured this out. Both cars are now chopping pretty good with their little medium cams and drivability (and performance) is also good. How I arrived at the solution was by first following the instructions in this video:

https://youtu.be/SIkrHnKtRIk

Then there were specific issues with each car where I had to go in and make my own version and custom corrections. The truck did not like the settings from the video for drivability, I had to put it back and create a hybrid tune of my own. The car did better but was pushing at red lights so I went in and corrected that. Here is a little clip of the final product, the car lopes with a very healthy and aggressive chop at idle too.

https://youtu.be/JPobJUnqjDQ