Couple of things, The 1600RPM cells are a little troublesome. Seems like minor changes cause that area to swing radically one way or another. Also, when you guys have areas like the 2400RPM cells in my log. Do you guys still Copy/Paste Special/Multiply by % - Half the entire table or do you just work on the cells that need it Like lets say anything lean or more the -+ 5. Also as a side note, do you guys start out with lets say 10 cell hits in the histo and as it gets closer to whatever up the number of cell hits for the log? I've tried going in an roughing in certain areas of the map and I am getting closer.
One last question, why do the RPMS on the tables in the system for my truck skip 1,400RPM? Jumps from 1200 to 1600.
As a side note, I am studying up on tuning in Lambda. But I'm still not comfortable with it yet as far as setting everything I need up in the Scanner and converting it over to the VE Table. In the mean time Ill continue to work the table the old school way in AFR.
The problem with that cell is probably where its bouncing in kpa drastically and not a proper cell. they run 400 rpm jumps, just the resolution it uses. its pretty close to idle so kind of hard dialing those in to precise measures. what afr are you hitting around those areas?
Personally I just go off what the wide band says and tune within 5 or 10 percent. if I run 14.3 cruising im cool with that, and also in boost if im at 10.8 or 11.3 im cool with that as well. Water meth helps in the boost and moderate timing will do wonders for longevity and human error
There are multiple strategies
The first thing I Do is general changes, make a log and setup filters so you can see when TPS > 3% only, and when the slope of MAP is positive, and when certain cells are steady state for more than 500ms, stuff like that. Make sure look at the highest and lowest numbers captured because averages are often skewed heavily by deceleration and other situations.
Then examine each filtered data map and compare them, look for consistent results in all the different filtered maps, then use the best cell counts to do the more fine tuning, and smooth surrounding areas using the best data.
This part is done quickly, don't waste too much time fine tuning yet.
I never want to cruise anything under 14.7, always shoot for 14.8 to 15.2
You can 14.7 to 14.5 coming out of steady state cruise, I will 14.0 to 14.4 in the lightly accelerating region 55-65kpa depends
Once you get the map consistent showing you 15's across the top cruise areas for increments of cruise situations,
you can start actually fine tuning. This is where you stop relying on filters and start rolling the mouse along the wideband data and using the slope and conditions of the wideband data line to determine whether the cell currently being occupied is true to the data or not. Look for long smooth lines/curves in the wideband voltage and account (in your mind) for transient delay. For example if you see rpm or map is increasing and the wideband is gradually richening up, realize than at 2000rpm or 2400rpm that the data collected for say 75KPA could really be from 70KPA due to transient delay. It takes a bit of experience and time and effort. By examining the wideband voltage instead of relying on the cell reports you get a better understanding of what the vehicle was actually doing at the time, it makes for a better fine tuning of a cell regardless of what number is averaged there.
When finished the wideband number on the gauge should practically remain still, almost unchanging for idle and cruise conditions, light load transitions, etc... hovering near 14.9 in my case
Thank you for the tips, For lean cruise have you had a noticeable difference in fuel economy? Not really what I'm shooting for just asking out of curiosity. Ill get to working on my filters, By chance I'm pretty close to what you mentioned under cruise. But still staying a little lean coming out of steady state cruise +1-1.5% where it will finally transition to the rich side. so Ill work on getting those numbers down a little more. Going to have to revisit everything at the end of the month after I install my 4:10's but its great practice and the time its taking me to make changes is getting shorter with repetition. My main hold ups were mainly streamlining setting up VCM for what I was doing at that point in the tune but learned to save all my graphs for those specific parts of the tuning process so its just a quick load of saved setups.
There is very little difference from 14.7 to 15.2 in terms of economy but there is a huge difference in the carbon coating, long term cylinder and plug condition/color/quality after say 50k 100k miles, the plugs and pistons tend to stay cleaner, less carbon buildup, less blackening and deposits.
14.7 and richer ranges tend to brown things up, and may lead to unwanted deposits, it depends on the engine design. Modern cylinders like for LS engines are likely designed with a carbon pad or specific place to deposit carbon to control the flow of carbon buildup within a cylinder, depositing to specific places where it will do no harm. Thick carbon can break off in chunks so it is a concern for long term reliability of engines, how much carbon and where it goes over time, how it forms, whether its hard or sticky. I am just thinking out loud here based on what I Know about chemistry and experience with high mileage engines. Something else to consider is the wideband is averaging all cylinders, so when we see 14.7:1 there are very likely some cylinders 14.4 to 14.6 ranges, and some are perhaps leaner than 14.7. So in order to keep carbon deposits down for ALL cylinders you would shoot for 15's say 15.2:1 which will help ensure all cylinders are at least 14.7:1 or leaner, hopefully
I recently adjusted my injector timing and that spurred a re-tune of my setup, Ill see if I can post some logs and pics for you later to help see my a/f ranges. I Just accidently hurt my back though so im moving super slow and it hurts just to sit up so idk when
Starts kinda here, new injector timing caused an overall rich condition in the idle cruise, but it leaned out a little during transitions to load.
Mostly fixed the next day
What changed in the VE table
but also I made changes to injector size, injector delay, some transmission stuff, even the idle and torque management. It all fits together, the VE table is only one way to compensate for differences. For example transmission shift quality and timing will reflect how the VE table is used, how fast or how deep the cells move. The delay adjustments help with hot idle and heat soaking conditions. A ton of tiny adjustments all adds up to make the vehicle drive better, not just show us the right number.
Man, Cant wait till my logs look as consistent as yours. I am considering installing 4:10's with a Trutrac Helical LSD so I'm sure I'll have to revisit my table. I'm going to take a look at your files this weekend. When I get some free time, my work is crazy busy right now. Thanks for all the info and help you provide to this board. Along with all the other advanced tuners out there who are willing to share their knowledge.
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