VE coefficient tuning and tuning pointers for ls3 newbie

[Phill]

Hello, I have a 2008 ls3 C6 m6, I am trying to make a base tune for my 230/234 114+2 cam I'm putting in. I am very new to this stuff. I know I should tune for maf first by calculating errors with my wide band AFr vs commanded AFR with my PE tables set to a constant (12.5 for me), and forcing the car to run in open loop, while adjusting the open loop gas (gear & p/n)tables to command 12.5 acrost the board. That makes sense. Then I can adjust my MAF via histograms, and fine tune it, then set PE's to what i actually want (what do you think? 12.7?)
from there I will play with timing.

After that is done, do I put the stock tune settings back in the Open loop "Gas (gear)" and "Gas (P/N)" tables? I'm not sure what to do at that step?

If my STFT's don't match up do I adjust MAF more? how do you change those?

And for the main question, how do I tune the VE coefficients??? is it possible? Is it worhtwhile? if it's not worthwhile (from my search's it looks like a lost cause) how the heck to I turn off the VE so it doesn't effect anything?

Attached is my best attempt at a start up tune that should get me in the ballpark for maf tuning, if you have a min, take a quick look.

Car; 2008 c6 with ls3 and M6
LT headers, CAI, 160* thermostat, No cats, cat back exhuast, 230/234 cam.

Thanks

This is my first time tuning, and it feels like that first day in advanced multi-variable calculus, everyone around my was smiling and noding their head, while I was trying to figure out if I was in the correct room....

[Bill@HPTuners]

I'd recommend the maf or sd custom operating system thats available for this application rather than trying to tune the coefficients in this case.

Much easier to tune a real ve table.

[redhardsupra]

everything you need to know about the coefficients based VE tables: http://www.marcintology.com/tuning/ParametricVE.pdf

[Phill]

Thanks RedHardSupra, however I think thats over my tuning level at this point.

How does one tune maf only? do I need to turn off the VE in anyway? Do I just tune the maf like I had planned and forget about the VE coefficient tables?

I'm assuming for the open loop tables I put the stock values back in when done?

Thanks again!

[Bill@HPTuners]

If you only want the maf in play you could set the dynamic airflow constant to tell the pcm to ignore the ve coeficients below a given rpm.

[redhardsupra]

if you understood the process of calibration tuning maf or ve is really one and the same at the conceptual level. the main idea is to get the fuel mass and AFR (from sensors), and equate it to the parametrized airflow model on the other side. Whether that model is MAF (3rd order polynomial), or parametric VE (30 zones of quadratic surfaces stitched together), then you just solve it for the parameters and you got the full calibration.

[DSteck]

You can get away with MAF only. I've done a lot of cars like this, and haven't had anybody complain of any sort of drivability issue that they noticed.

My personal car will be tuned to the teeth when it's done using both MAF and SD, but I use the enhanced OS from HP Tuners because I'm too lazy to use EQ_VE (the software to interpret the coefficients into a table, and then generate the coefficients based on a table you create).

To do MAF only, just set the high speed enable/disable values in Dynamic Airflow to something low, like 2 and 1 rpm.

[Higgs Boson]

At what point of modification would you say a GenIV needs to go MAF only, no VE? How much can the stock virtual VE/ve coefficient take as long as the MAF curve is tuned?
Intake?
Headers?
or Camshaft, stroker, forced induction, etc?

[redhardsupra]

that depends on the year/model of your car. older cars have hard limits of 512g/sec of airflow and 64lb/hr for injectors. I just spent some time on a 2010 camaro where the limits were 1024g/sec airflow and 128lb/hr injectors. WAY more power without hacking and/or lazyness

[Higgs Boson]

Hmm, I don't mean that, I mean how much can you realistically change about the airflow of the car without touching the VE tables thereby necessitating VE disuse (if you don't tune the VE of course)?

[redhardsupra]

none

[Higgs Boson]

So anything other than a bone stock car or truck should be MAF only as soon as you add an intake or exhaust?

or the alternative of tuning the VE coefficients for minor mods? i would def see doing it for cams and more......

[redhardsupra]

I hate to admit it, as I really enjoy the hybrid mode, but pure MAF works quite well on these cars.

Practically speaking, having a half-tuned car isnt too bad if the discrepancies are light. There might be a stumble on transition or something, but in most cases it would work fine. But where do you draw the line? Intake/exhaust, but no cam? I don't like hard rules like that...

The problem lies not in what values the two airmass estimation models they spew out, but knowing when you're using which one. If all you do is drag and thus you're interested in WOT only, then the computer is gonna go to pure MAF for you without any changes to the tune. But if you live in a real world, and you want to cruise around, or gawd forbid go to a track with left and right corners, and you need to modulate your throttle, and throttle transitions need to be smooth, without stumbles or hesitation, then you're gonna need both modes to agree at all times. And the only way to get that is to tune both. Or one, and use only that one. Remember they're both doing the same job. They're more of a 'second opinion' than 'coke vs pepsi'. If MAF works for you AT ALL SITUATIONS, great, use that. If VE feels better, use that. If you're mindbent to have the computer operate as intended, then you're gonna have to do both.

[Higgs Boson]

It's interesting, I'll switch my truck to MAF only as I installed an intake tube and tuned the MAF for it but even so in hybrid mode it will surge right after I start it now. I'm going to see if that stops it.

[Phill]

My personal car will be tuned to the teeth when it's done using both MAF and SD, but I use the enhanced OS from HP Tuners because I'm too lazy to use EQ_VE (the software to interpret the coefficients into a table, and then generate the coefficients based on a table you create).

where would one get this EQ_VE software? or the enhanced Operating system for HP?

Since I am new to this I will tune for maf when it stops snowing here and warms up (2' on the ground today) and see how she runs, and being as how I over think most things, I will probably end up attempting tuning the coefficients. From Supra's read and from what I'm finding in searches, it looks like its a matter of using the coefficients I have to create a VE table, then modiflying it, and using a function to work backwards to the correct coeffiecients.

Fun......

[02Ls1]

You can get away with MAF only. I've done a lot of cars like this, and haven't had anybody complain of any sort of drivability issue that they noticed.

My personal car will be tuned to the teeth when it's done using both MAF and SD, but I use the enhanced OS from HP Tuners because I'm too lazy to use EQ_VE (the software to interpret the coefficients into a table, and then generate the coefficients based on a table you create).

To do MAF only, just set the high speed enable/disable values in Dynamic Airflow to something low, like 2 and 1 rpm.

How much boost will the MAF can handdle on this e38 cars n trucks?

[redhardsupra]

MAF is about airflow, not boost. so you gotta do some math to calculate airflow from rpm, cylinder volume, boost, temps, and volumetric efficiency.

[DSteck]

How much boost will the MAF can handdle on this e38 cars n trucks?

In a 4" housing, I've gone up to about 750-800whp before the MAF is maxed out at 12,200 Hz. The enhanced OS will let you take it to 15,000 but I don't know how much I'd trust it up there.

[02Ls1]

Thats good to be on pure MAF, how much lb of boost was at 750-800whp?

[DSteck]

On a 427, 9.5 psi.