Newbie - 06 TBSS, VE corrections overshooting

[Maxspeed96ct]

Hey guys , im not new to LSx motors but new to tuning.

Im trying to attempt a speed density tune on my bolt on /stall cammed ls2 06 TBSS


My corrections keep overshooting, not sure when Im forgetting.

For the WOT wideband portions I have the cell min count set at 4.
During STFT tuning I had it at 25 but

Im using a AEM wideband, looking at my histograms im getting accurate a/f commands and accurate readings to the gauge.


My problem is every time I do copy -multi % special half the numbers overshoot.

What am I missing. Please take a look at my files.

Thanks

[BigDaddyCool]

Ensure you have calibrated your voltages for the AEM so the guage and what shows on the scanner are the same......... theres a thread on here somewhere for how to do that.

Second... VE is HARD to learn how to approach ...... You need to look at mins and maxes vs TPS and steady state scenario's 'manually' to see how that histogram is......... and make some decisions about how to start.

Dont focus on singular cells....... you need to interpolate the data and water it down so you have smoother changes per change otherwise you'll swing wildly too far the other direction.

Perhaps start again, copy and paste the histogram, then times the changes by .4 and smooth the changed data three times, drive, repeat...... see if you get it any closer...... It takes alot of effort and time to learn how to SD tune, maf is alot quicker for those starting out.

[Maxspeed96ct]

Ya seting up the aem was a pain but I think it's Damm close . I can tell the actual a/f logged on the histo matches my gauge readings . , I've had speed density on my previous cars and love the driveablity and performance . So I'd love to do it on my Tbss .

What do you guys recommend for a min AFr error % histo cell count for normal cruising
And a min cell count for wot .

I initially had it at 0 which May have been part of my prob . Then I put it to 25 then 4 on the wot pulls .


Can you give me more details about multiplying just my changes by .4 on to of the percent by half .
How exactly should that be done .

[BigDaddyCool]

I dont use min cell counts for the most part, i watch the car while driving as my afr guage is built into the dash......... and do a wide linear change based on min vs max etc......

Cell counts are hard because either way you need to make entire changes across the board......... even at wot, alot of the time its more about the shape of the ve then really the % .....

VE works much differently to maf really.......

So with the percentage thing, open your original file as comparrison, then make your changes compare changes then mutiply by .4 and smooth 3 times........ its a good starting point as you need to workout how your ve table need to look first.

[Maxspeed96ct]

I think I found part of the problem , I was hitting pe In some spot and using the same histogram for my normal stoich tunning and my wot . I'm going to set my pe back up to the factory 5000 this time vs the 3500 I'm at now . And be easy on the throttle

Now that being said , how to I correct for pe ? Do I set up another histogram ?

Or how do I add a filter out pe ? Obviously I don't wanna turn off pe ..

[Maxspeed96ct]

So I started from scratch last night , kept it easy on the throttle and stayed out of pe . got the stft very close . I'm Going to do some Wideband ve corrections next .

My question is : what do I do about pe and wot tunning ?
Will the ve AFr error % vs comanded automatically correct for the commanded pe ? Or do I need another histogram ?
I don't want to chase my tail over correcting again .

[BigDaddyCool]

I only tune with wideband for everything......... but its hard for wot, 2nd gear standstill pull to redline..... you have lean spike on full throttle which you have to learn to ignore... as it takes a sec for the wideband to catch up

[Maxspeed96ct]

So same histogram ? The % error shouldn't get screwed since it's adjusting againt the commanded AFr right ?

[BigDaddyCool]

Same histogram only AFR Error obviously which is worked out from the commanded yes.....

Typically with VE I run completely off wideband but with the O2 sensors still connected they still report STFT even in open loop..... so I can guage basically how the car will run in closed loop .... eg. Some spots might be spot on with fuel with the wideband but the STFT's might be somewhat rich..... so half the time I'll lean that spot out a touch......

I have my 4 o2's plus my wideband... So I have alot to work off.... I've had much greater sucess using the histogram report more as a guide and looking thru the scan itself to determine what changes I should make where....

[Maxspeed96ct]

Thanks for your help , I ended up starting over . Set the stft , this time I was very easy on the throttle an stayed out of pe .
I only touched up the ve in open loop Wideband once or twice . Then did my wot pulls seperatly ignored the non pe cells .