Change boundry for MAF

[PurplePiss]

Which table do you change on an LS2 to make the fueling dependent on the maf and not a highbrid of the VE table and Maf? I believe it is RPM dependent. 4000 rpm?

[EC_Tune]

Dynamic Airflow tab.
Hi RPM Disable, & Hi RPM Enable
Drag those down to make it MAF dependant

[PurplePiss]

Is this the only thing you would need to change or should you move the map and boundry stuff also?

Is this a smart thing to do? Since we can not tune the VE table, I was planning on running solely off the maf. I assume it would still use the ve table if the maf failed.

[PurplePiss]

ttt

[S2H]

Is this the only thing you would need to change or should you move the map and boundry stuff also?

Is this a smart thing to do? Since we can not tune the VE table, I was planning on running solely off the maf. I assume it would still use the ve table if the maf failed.

yes..I believe thats it

[PurplePiss]

Stock it is set to High rpm disable at 3600 rpm and re-enable at 3500 rpm. Should I set it to 1100,1000 respectively?

Is this a smart thing to do considering the VE challenges the LS2 has?

I have been making changes to the MAF Hi and Lo by turning off the LTFT and STFT, then logging hi maf % afr error and lo maf $afr error. I make 2 or 3 logs and then average the numbers, then apply it to the curve in excel and then copy it in. When I do this, I overshoot. Just like when I was tuning VE. Any ideas?

What filters do you use to get good maf data. If I look at the + and - filters on these 2 histograms it shows +16 to -13. I think it is averaging in deceleration (dfco/cot is turned off). Do you filter ETC >15%, Map > some value? Do you throw out AFR over 5% and less than -5% since I'm pretty sure my curve is close? The reason I ask is I will have a smooth curve, but the log data shows -3,-3,0,4,-2,-1,4,2,-3. How can that be? Again, is this from letting off while driving?

[Monster'06]

When I do this, I overshoot. Just like when I was tuning VE. Any ideas?

Make more changes on a smaller scale. Using larger averages is good to get "close", but when fine tuning, you should use smaller increments and verify that the change was correct.

[ZO6_Bryan]

This has got me thinking. I know this is Gen IV section but should still apply to tuning both gen III and Gen VI. On the Dyn. Airflow tab under steady state the Low MAP Delta to enable steady state is only 0.00 kPa for my 02 ZO6. With the cam I put in it the MAP is jumping around at idle so much it must not ever enter steady state fueling at idle. I think if I increase this value it would use the MAF signal while idling and solve some of my surging issues. What do you think? BTW I've already VE tuned it or it wouldn't idle at all. It's a 232/236 585/585 112 +2 cam.

[SICK WS 6]

Whoa? Huh?
What did I miss here? So are we not to be using the VE anymore since it appears to be "different" on the LS2?
So there's a way to make the computer just use input for MAF over a certain rpm?
Sorry for the ignorance here, maybe someone could explain to me what's going on?

[redhardsupra]

it is different on LS2. the new style VE table (i call it GMVE, or a normalized airmass table) is much more sensitive to changes, so unless you have a way to normalize airflow, you cannot really tune it. the problem with that is that to normalize conditions you'd have to have a really good model for the manifold temperature (aka tune the temp bias table), and we don't have that yet.
so for now, i told PP to tune with OL MAF setup, as MAF does inherent and automated airmass normalization.
this is a much deeper topic...

[SICK WS 6]

So it just revolves around getting the bias tables accurate to make the ve work.
Now I'm even more interested in seeing (and having your thoughts on) soundengineer's future bias tuning writeup.

[5_Liter_Eater]

I had been running in closed loop MAF for a few weeks and wanted to re-verify my MAF table because it seemed my WOT was running fat by looking at the AEM gauge, I thought I may have some positive fuel trims. So I disabled closed loop and set the high RPM disable to 600 and the re-enable to 500. So in theory I was running solely off the MAF table. It idled and drove fine. I didn't notice any drivability problems by omitting the VE table.

This is a neat trick that is not talked about much. People always disable the MAF to tune the VE table but not vice-versa. I think setting the dynamic airflow parameters exceedingly low should be included in any WB MAF tuning procedure.

My MAF table was still pretty spot on BTW. Thinking of leaving it this way. Maybe re-enabling STFTs.

[Chris@HPTuners]

it is different on LS2. the new style VE table (i call it GMVE, or a normalized airmass table) is much more sensitive to changes, so unless you have a way to normalize airflow, you cannot really tune it. the problem with that is that to normalize conditions you'd have to have a really good model for the manifold temperature (aka tune the temp bias table), and we don't have that yet.
so for now, i told PP to tune with OL MAF setup, as MAF does inherent and automated airmass normalization.
this is a much deeper topic...

it is exactly the same for the LS1, we just show the units as % for the LS1. But since GM got the cylinder volume wrong for a lot of the early LS2's we decided to show it in the true PCM units (grams.kelvin/kpa)

the newer speed density calcs for the E38/67 ECM's (the filter coefficients) it is common for tuners (and even GM) to lower the disable RPM's so that the MAF is used completely, especially on FI apps.

[SICK WS 6]

So I disabled closed loop and set the high RPM disable to 600 and the re-enable to 500. So in theory I was running solely off the MAF table.
This is a neat trick that is not talked about much. People always disable the MAF to tune the VE table but not vice-versa. I think setting the dynamic airflow parameters exceedingly low should be included in any WB MAF tuning procedure.

So you could do this, and log MAF - AFR error % to tune the MAF curve after getting the ve dialed in then?
And this should/would work better than logging MAF hz - airflow and rescaling the maf curve that way?

[5_Liter_Eater]

Thats exactly what I did. You'd tune it the same way by plotting the AFR error against the low and high MAF curves except with the airflow calc out of the way you are assured that your AFR error is 100% due to MAF curve error.

[SICK WS 6]

Sweet. I'm learning.

[PurplePiss]

So Chris, can you help us out? Is there something that could be done software wise?

[5_Liter_Eater]

What needs to be done software-wise?

[SICK WS 6]

Yeah? What are you wanting him to do?
It was my understanding that we can still do the ve table and maf with AFR error %, and that soundengineer is working on the bias table how to?

[5_Liter_Eater]

All these parameters allow us to do is take the VE table out of the equation. You can do it temporarily just to tune the MAF more accurately and change it back when you're done MAF tuning or....leave it at an extremely low setting to have the VE ignored alltogether and make it act more like an '06+ LS2 (Can't rember the VE'less LS2 PCM designation). I'm going to put mine back in closed loop with the VE essentially disabled and see what my trims look like. Apparently the MAF does a better job of normalizing the temp/humidity/etc.