VE tuning again

[maudyZ28]

Hi all, im new here and this is only my second post, 1st is in the trans stuff :D

Anyway, i have a 1999 camaro Z28 with CAI and k&N and cat back at present and want to learn this VE stuff before I get my headers and LS6 intake on that are in my bedroom.

I have done EGR, AIR and rear O2 delete and all is fine

I don't have a wide band

I have read the calcVE tutorial by Weatherman Shawn

From what i understand i want to adjust my VE table by the BEN factor that is measured, in this case using LTFT, but I have also heard i can use STFT?? Secondly is this the method failing the MAF or not?

From the stuff I have read and other auto VE etc, I think i need to fail the maf, thus VE is used, make sure commanded fuel is 14.63 and STOP PE (which currently commands 11.7 wtf??) Then i measure a BEN factor after a drive and multiply my existing VE with it then the VE is prob quite near, but I need to watch for knock and set it to zero retard so i can still get fueling? Also the 99 OS says there are like 64 CL modes? and each has a different O2 shift point for rich to lean?? not all 450 mv. I'm a little confused :help2:

[joecar]

Hi maudy,

Try Weatherman's first, see what result it produces, become familiar with looking at the logs and calibration [ use the link feature to highlight the operating cell in the calibration tables ], and use your wideband to monitor the process...

Then later, try doing AutoVE and AutoMAF... they are more involved and require you to sanity check your steps and your wideband.


You'll find that 11.7 is cat protection kicking in, GM wanted to be ultra safe.


For AutoVE you may want to leave PE enabled and set it to something like 12.6... you want to avoid a lean condition under load (any significant load at any rpm). Yes, fail the MAF and disable CL, LTFT, STFT.

Use the throttle progressively and steady to get good data so the transient filter doesn't throw out too much data.

Watch for knock, but don't disable knock retard (it protects your motor), just filter out those log samples.

CLMODE: look at tables B4107 and B4105... supposedly (from GM) the NBO2 switch point varies with airflow... a new replacement NBO2 probably has a switchpoint that stays closer to being constant at 450mV.

Cheers
joe

[WeathermanShawn]

Hi all, im new here and this is only my second post, 1st is in the trans stuff :D

Anyway, i have a 1999 camaro Z28 with CAI and k&N and cat back at present and want to learn this VE stuff before I get my headers and LS6 intake on that are in my bedroom.

I have done EGR, AIR and rear O2 delete and all is fine

I don't have a wide band

I have read the calcVE tutorial by Weatherman Shawn

From what i understand i want to adjust my VE table by the BEN factor that is measured, in this case using LTFT, but I have also heard i can use STFT?? Secondly is this the method failing the MAF or not?

From the stuff I have read and other auto VE etc, I think i need to fail the maf, thus VE is used, make sure commanded fuel is 14.63 and STOP PE (which currently commands 11.7 wtf??) Then i measure a BEN factor after a drive and multiply my existing VE with it then the VE is prob quite near, but I need to watch for knock and set it to zero retard so i can still get fueling? Also the 99 OS says there are like 64 CL modes? and each has a different O2 shift point for rich to lean?? not all 450 mv. I'm a little confused :help2:

Just to expand on Joecar's response.

You could plausibly use STFTS, but they are more 'temporal' and the peaks from High-Low can be greater. Sometimes a 1% chance in STFTS does not always equate to a 1% chance in MAF/VE airmass..I have only tested it rigorously using LTFTS. But, I think it could be done using STFTS..

The method does not require failing the MAF. In fact it uses the MAF to calculate the VE Table (its uniqueness). But, the formula is very accurate. So, if you were to fail the MAF at some point, the Calculated VE results would very accurate.

I think in reality there are not 64 CL Modes. I believe they are bunched up into ~ 9 (combined in successively higher Airflows). Some of the earlier year OS's have differing mv. I believe it has to due with the cooling of the narrowband sensors at various airflows. Basically it is very confusing. I and others have had more luck just making them a uni-value. Otherwise, it seems to add to a very peaky VE Table (opinion)..

Joecar had a great synopsis of the various types of tuning that I think was a great summary. You might want to check it out...http://forum.efilive.com/showpost.php?p=119640&postcount=21.

There are many good method to tuning. Let us know if we can help..

[maudyZ28]

thanks guys, i think im kinda getting it. Ill do some logs first.

Joecar, sorry i dont have a wide band yet hense I cant check whats happening and have to 'trust' the fuel trims. I disabled B0701 cat protection, and am removing them when i get the exhaust done, hence rear O2 code set to NOT REPORTED , is it just standard that it commands a 11.7 for 'cat protection' at WOT all the time??

EDIT just checked and B3618 PE based on rpm is 0.8 Lambda, so 14.63*0.8 ~ 11.7

weatherman, i have read you tutorial again and again and guys i'll spend this weekend logging to see what my engine does, and to check o this CL mode. I dont have the wide band so will have to see if its ok and i dont get knock. Before I start do you think I should just reduce the PE (as above at 0.8 to 0.86??? ) all over to reduce the commanded to about 12.6??

[WeathermanShawn]

I would go for 12.6 AFR. I.E., unless governed by local law I would 'Disable' Catalytic Converter Protection. Its the one that makes WOT overly rich. If you have cats, just stay away from 2-3 consecutive WOT runs that last over 8-10 seconds. P.S., I have cats and have run that set-up for years with no problems.

Thats fine on the O2 Code. You can set it to No Report (check Emissions Laws). But 'Disable' on Cat Protection will get the job done.

Just monitor any KR. At your convenience I would get a reliable Wideband with Serial Connection if possible. You can get 90% of the CALC VE Table done via your Narrow-Bands. Just make sure they work! But, again..as soon as you can advise a wideband. Don't want your engine to blow up! So, stay conservative on WOT Spark...

Post up any tune and log when appropriate. Within 1-3 runs you can usually get things ironed out.

Good luck..

[joecar]

Disclaimer: offroad usage in Mexico or the Northern Territory only.

[5.7ute]

Disclaimer: offroad usage in Mexico only.

Or the Northern Territory.

[joecar]

Updated disclaimer...

[maudyZ28]

thanks guys, well im in UK so 'off road use only' IE on my drive way only :hihi:

yeah no cats weatherman so think 12.6 will be fine, I'm going to leave the spark standard, see how it runs at WOT and maybe only advance slightly. I think it is only at 24 deg or so now and heard most LS1s like 27 -28 but get some knock up high, so i wont go that far.

Also could someone tell me when the PE table is used, i assume its part throttle when PE conditions are met, Ie PE enable at rpm and MAP and use the table (sorry dont have code im at work) and uses B3618 only at WOT ?

Finally how should I expect VE to change vs stock? up or down or a change up and down in different areas? the LS6 intake is going on this weekend so and im not changing the tune till after. I have some other ideas or thoughts but ill test then first, due to my nature i try and find out as much before i mess it up, but i need to test these so i will (and ill be careful :grin: )

[WeathermanShawn]

MaudyZ28:

Read somewhere LS6 Intakes do not really need more than 25 degrees of spark at WOT. I would start with that until you get wideband.

As far as B3618 it is probably easiest to make it all one value to start with. You can get more sophisticated with a PE fuel curve as you advance. B3616 is RPM vs TPS.

I would imagine headers and LS6 Intake would increase VE 5-10%..lower down low, then after 4000 Rpms you should see an increase. Somewhat of a guess on my part..I did not get into tuning until I had H/C..

Have fun..:grin:

[maudyZ28]

yeah thats what i thought

Also im still running 99 OS so my PE is also different I have some 3D maps of throttle and MAP pressure I think. Again, ill have to check later :D

[maudyZ28]

I just check i was getting confused with the commanded fuel when in Open loop (B3605) lol

ok so i set my B3618 to 0.86 lambda, AFR = 12.6

i only got a bit of knock just before pulling off throttle in 3rd at about 4000 rpm, interestingly this was 1.8 deg, but before running 11.7 it pulled 4 deg at the same place, but again right before im off throttle so dont know if its anything to worry about

also in 2nd at about 5500 it pull 1 deg too, i thake it in the current set up that its a bit lean?

However it was hot out, the other run my IAT was 8deg C, here its like 24 deg C :(

[WeathermanShawn]

Not a whole lot of knock.

Whats interesting is that your LTFTS are averaging ~ -9%. Since it looks like you are running MAF-Closed Loop..looks like your overall MAF Calibration might be too high. If staying closed-loop you want them as close to zero as possible.

Have you altered your MAF Calibration Table?

[joecar]

At WOT it's getting lean (the HO2Sx1 voltages show a downward trend).

[joecar]

If you're using lambda units, pay careful attention... it may be easier to use EQR units (> 1 is rich, < 1 is lean).

Remove APP and FUELREM to get your pid channel count to 24 or less for fastest sample rate.

INJFLOW is almost constant...? I thought it was supposed to go up with airflow.

At 6000 rpm, 97+kPa, 100%TP: I would expected MAF to reach about 270+g/s... what vehicle/engine/mods...?

[WeathermanShawn]

Wow, good eye on the O2 mv..Missed that.

Joe, I assume he is logging INJFLOW as in B4001 (g/s)..OS 09360361? If that is the case then I think he has hit between 0-5 Kpa Vacuum. I thought that followed B4001?:confused:.

Yea, I don't understand about the MAF Airflow (g/s). Its odd, because all his Trims show -9..Normally you have to fatten up the MAF (overestimating Airflow) to get that high of negative Trims.

You got me worried about the Lamba conversion. Be very careful using Lamba..Perhaps post your tune..Promise it will all be constructive review. No one is out to 'slam' it.

Maybe he is running CLSD??? I can't tell from the log..

[joecar]

Of course...:doh2:...INJFLOW follows B4001 and he has a MAP-referenced regulator.





[I]

[WeathermanShawn]

Joe..this is the second time you have been wrong in two years!!!:)..

I am at about 20-30 boo-boos..:grin:..

[joecar]

Are you kidding, I'm either wrong or falling into a hole more than several times each day...:doh2::doh2::doh2::doh2::doh2::doh2:

[joecar]

Actually, his INJFLOW varies from 3.3281g/s @ 100kPa MAP to 3.6484 @ 20kPa MAP...

so he might actually have a non-referenced FPR, in which case his rail pressure would calculate to 57.5 psi...

and he has 23 lb/hr @ 43.5 psi injectors...?

So, I was wrong again, about his FPR... :hihi:

[joecar]

At the cursor in the pic in post#14:
5529 rpm, INJFLOW=3.3516g/s, AFR=12.603, cylair=0.6713g.

cylair is calculted from MAF, so assuming MAF is reading ok:
fuelmass = airmass/AFR = 0.6713[g]/12.603 = 0.053265[g]
IPW = fuelmass/INJFLOW = 0.053265[g]/3.3516[g/s] = 0.0159[s] = 15.9[ms]

So without considering injector dead time and ramping flow:
DC = IPW*RPM/1200 = 15.9[ms]*5529[rpm]/1200[%/ms/rpm] = 73% which looks plausible.

[joecar]

...Yea, I don't understand about the MAF Airflow (g/s). Its odd, because all his Trims show -9..Normally you have to fatten up the MAF (overestimating Airflow) to get that high of negative Trims.

...

Maybe he is running CLSD??? I can't tell from the log..

Shawn,

Maybe he is running CLSD...

maybe his MAF is ok (I still expect it to read higher... have a look at some of your own logs)...

Or maybe there's something else...

[maudyZ28]

ok guys a really big thank you for the help. I should ahve explain earlier, this is the STOCK tune with only the PE vs RPM B3618 changed. Whats the problem with using lambda here? I was running as the normal tune would with air flow from MAF at 4000 rpm (maybe why the know comes becuase it changes from VE table and MAF to full MAF??) its running in CL mode also

The car is a camaro Z28 A4, basic engine mods, SLP lid and bellow with K&N but I have cut the filter tray so it 'scoopes air up from the ground' and it ahs a cat back, AIR, EGR and rear O2 deletes. thats all, im putting my LS6 initake on today.

I logged calculated injector flow rate cause my OS wont let me do the injector duty cycles. From the downward trend is this becuase the LTFT are pulling fuel (presume thats what -ve does? ) EDIT, LTFT are at 0% at WOT so then if the car is leaning I muc richen it up a bit??? should i need to richen up to 12.4 or something after 4000 rpm to account for MAF calculated air flows?

[WeathermanShawn]

Maudy:

Joe, I don't see any MAF DTC (log), so I will assume MAF-Enabled..

Maudy, no we are just trying to figure out your tune and log. Injector Flow Rate is always one of the most important parameters. A lot of times people will post 'their tune is stock', then after 1-2 weeks trying to figure something out, they will mention, 'Oh, I did change this..I forgot to tell you'.

So do not take it personally, I always like to see a person post their tune along with their log. It can save a lot of time and hassle.

I do not know what to think about your log. Something does not seem right with your Trims vs your MAF. Is that a stock MAF? Is the car mechanically sound? How many miles etc?

Until you can get an accurate wideband hooked up, a lot of your fueling at WOT will just be guessing. Unfortunately you just can not adjust anything until you know your AFR's. On my car I have AIR disabled (its gone), no EGR, but I do have Cats. So I don't know if you have an air leak, cat clogged..something just does not make sense..

Any chance you can get a wideband on in the next few weeks?

Edit..

Maury..any chance you did that log right after filling up with gas? A lot of times, you get wildly negative trims after a gas fillup (temperature of new fuel). Also, what is the Ethanol content of your fuel?

Thanks..

[maudyZ28]

weatherman, yeah its literally totally stock i only messed with the table of PE commanded fuel, thats it

Yep full tank of gas, just filled up, so that could be that :)

here the tune, like i say stock and it all runs fine, 100000 km and strong runner

just in a mood now, broke the oils pressure sensor/switch, didn't know the brake booster was wrapped around it :( and it snapped, and i dont have tools to get it out, plus i dont even know if i can get a new one, im in UK and have to ship from US usually, hopefully i can find one, still dont now how im gonna get it out, or the other back in!

[WeathermanShawn]

Just checking (sanity check)..You have a 1999 Camaro 5.7L Auto. May not be a big deal, but are you running the manual OS?


weatherman, yeah its literally totally stock i only messed with the table of PE commanded fuel, thats it..

When I compared a stock 1999 Camaro against your tune, I found the following calibration differences: (See Attachment). Thats actually a lot of changes from stock???:confused:..

I am not sure if you are better off going to the correct OS..I really feel like I am missing something about your tune..I.E. you have changed an awful lot, including dynamic fueling. I am trying to understand why you said you only changed PE?


Anyway, I would try another log without a fresh tank of gas. It only takes about 10-15 miles for fuel trims to settle after a fresh tank, so perhaps your Trims will be more representative on the next log.

Perhaps another tuner can look it over. Maybe the changes are no big deal. Its hard to know if any of your changes have affected your airflow calculations and fueling.

Its a little over my head right now..:confused:..

[maudyZ28]

no im using an auto OS, my LOG says manaul cause I forgot to change it to auto when i input the VIN

On holden crazy the auto camaro tune has a different OS becuse its a convertible. But the pontiac firebird auto and manual 99 has same OS number as mine. 09360361

I haven't changed any of that air flow stuff, I have only change the B3618 that is it on the engine side (rest is trans and not relavent), if i do a compare with the 09360361 pontiac firebird 99 auto they are not different (throttle cracker is 0.7% out thats it, and my trans stuff), if i do the camaro manual there is a LOT different as you point out. My car is a UK spec too and most things on it are from the firebird/trans am, rather than a camaro, thus i prob have a firebird tune?

the tunes are below, including my stock unchanged on that i downloaded from my PCM, no changes

[WeathermanShawn]

Thanks for the clarification.

This stuff is never easy. I would just say try another log now that the new fuel has settled.
Think I got it now on your OS...:cheers:

[maudyZ28]

yeah, I compared it and was like WTF I havent changed anything ???? haha

I'll do a new log as soon as I can drive the car, snapped the oil pressure switch when changing the intake, so now i have to wait till tomorrow and ring a Yank specialist over here and see if they have the part, if not its going to be a long wait getting on from the US :(, and I hate public transport

just check the log again, and when i floor it the car goes open loop?? I need to do more logging first, just wanted to check how much knock is bad, ie is the 1.8 deg safe??

[WeathermanShawn]

Personally I do not like any legitimate KR. I usually lower spark by 2 degrees if I get it. Real KR usually goes away with less spark.

It is normal to go 'open-loop' when you punch it. PE Mode is actually considered a form of open-loop. Your O2 sensors are being ignored and all the fueling calculation is being made from IFR, airmass, etc (the real part of tuning). Thats where the wideband helps. You can sometimes be rich at part-throttle and lean at WOT.

Joecar was evaluating your O2's during WOT (open-loop). Without a wideband some tuners can observe their O2 mv's and have some idea of whether you are going lean or rich.

That one is above my head.

Later..

[joecar]

I'll look at your files later tonite...:)

[maudyZ28]

ok guys, i did a scan tryed to follow the calcVE tutorial, but like an idiot didnt read the end conciderations so its all invalid. But If you could have a quick check of the log i would apprichiate it. Also there is an issue with the calc VE map I have done, is this becasue I didnt turn my MAF down etc?? or is it the calc_pid file?? plus i forgot my O2 like a **** too :(

[WeathermanShawn]

For some reason it looks like it did not log DYNAIRTMP.DMA. Not sure if you validated the PIDS or not?

The good news is that it did successfully apply your LTFTBENS against your MAF Frequencies. In general, your LTFTS were pretty much in line.

A quick look at your log reveals that if you can successfully log DYNAIRTMP.DMA, you should be fine. Since your DYNCYLAIR.DMA is generally 10% higher than CYLAIR.DMA, I would predict that a lot of your VE Table values will lower (thats normal).

Logging your O2's help..but the CALC.VE Table formula requires DYNAIRTMP.DMA..thats all I can see you are missing.

Not bad. Try it again..:)

[joecar]

I'll have time to look at your file later tonite...

But in the mean time, add 2 blank lines at the end of your calc_pids.txt (otherwise the description of the last pid gets messed up).

[joecar]

So the 1999 OS doesn't have DYNAIRTMP_DMA...?

[maudyZ28]

thanks guys, yeah i figured it means my MAF calibration is pretty much on according to the drive.

the DYNAIRTEMP_DMA is the 'charge temp' right?? It said it WAS NOT valid. The only thing I could do was to use intake charge temp and change the weighting into the tune to use intake only??? OR could I make a PID somehow in calc pid file (how would I make my own) to roughly account DYNAIR_TEMP via intake charge, coolant temp and the average blending factor which is ~0.4 when airflow is above 60 g/s (blending factor B4901).

How would I make a PID for it, or set it up, i want to make
DYNAIR_TEMP ~ ({SAE.ECT}*0.04)+({SAE.IAT}*0.96) ??

Also noticed i put my displacement in the calc_pids as 5667 (cc) NOT 5.667 litres.

Weatherman, from what I understand then the CYLAIR_DMA is from my airflow on the MAF only and the DYNCYLAIR_DMA (SD) is from the VE table soley?? SO when going on my drive do I want to enable MAF at 400rpm so LTFT are base upon what fuel this commands or could I run soley on VE table and then the LTFT are from VE table as it stand and then I can change it based upon the calc VE??

I think it UNDERSTAND :), the idea of this tune to see what LTFTs are as and then the to adjust the VE accordingly to if the engine says its currently running rich or lean on average? And do I set all CL modes to 450mv?? rather than the current B4105 table

Also guys, I think the small bit of knock im getting is not real but from vibration maybe as it happended when gearing down to first then decayed away in 2nd all through the revs so its not pre-det?, should I make the knock less sensitive or leave it for now just to be safe.

Sorry for the essay, but trying to understand how the engine is working thus I know what the changes do

[WeathermanShawn]

thanks guys, yeah i figured it means my MAF calibration is pretty much on according to the drive.

Agree..Your LTFTS looked pretty good overall. As you progress with the Tutorial it looks like relatively minor changes to your MAF Calibration Table.

the DYNAIRTEMP_DMA is the 'charge temp' right?? It said it WAS NOT valid. The only thing I could do was to use intake charge temp and change the weighting into the tune to use intake only??? OR could I make a PID somehow in calc pid file (how would I make my own) to roughly account DYNAIR_TEMP via intake charge, coolant temp and the average blending factor which is ~0.4 when airflow is above 60 g/s (blending factor B4901).

You can make your own look-up table. It has been discussed in some recent threads. If you have to go that route, it can be done using a calculated pid..

How would I make a PID for it, or set it up, i want to make
DYNAIR_TEMP ~ ({SAE.ECT}*0.04)+({SAE.IAT}*0.96) ??

See above..

Also noticed i put my displacement in the calc_pids as 5667 (cc) NOT 5.667 litres.

That may be a problem. I would try Liters..

Weatherman, from what I understand then the CYLAIR_DMA is from my airflow on the MAF only and the DYNCYLAIR_DMA (SD) is from the VE table soley?? SO when going on my drive do I want to enable MAF at 400rpm so LTFT are base upon what fuel this commands or could I run soley on VE table and then the LTFT are from VE table as it stand and then I can change it based upon the calc VE??

Yes, you have the concept down. In the purest form changing the enable MAF to 400 Rpm will ensure all airflow corrections are from the MAF. Whether you use 400 or 4000 Rpm's, the LTFTS usually 'merge' by the 2nd or 3rd run. Your choice, but 400 Rpms is the 'purest' choice.

I think it UNDERSTAND :), the idea of this tune to see what LTFTs are as and then the to adjust the VE accordingly to if the engine says its currently running rich or lean on average? And do I set all CL modes to 450mv?? rather than the current B4105 table

You are a quick learner. You have the idea. For your tune, changing the CL modes to 450mv may not be necessary, especially if you are keeping the stock mv table. With cams etc, a straight 450mv may be slightly better.

Also guys, I think the small bit of knock im getting is not real but from vibration maybe as it happended when gearing down to first then decayed away in 2nd all through the revs so its not pre-det?, should I make the knock less sensitive or leave it for now just to be safe.

You could probably leave as is. I have a very aggressive KR recovery rate. I have included an example. It still detects KR, but IMO there is no need to have 10 seconds of KR recovery..if it is real, it will return.

Sorry for the essay, but trying to understand how the engine is working thus I know what the changes do

Essays are allowed. You have a very good understanding of the method. You might check with Joecar on that DYNAIRTMP.DMA Pid..I really thought a 99 OS could do it.


Good luck..You are progressing quite well!

[maudyZ28]

haha, thanks for the quick learner comment, im a scientist by day (well just qualified with 1st class degree in physics and now doing a doctorate) :hihi:

but cars is my hobby and passion.

Anyway, i've played with the tune, set MAF enable at 400 rpm
Set all closed loop modes to 450, above mode 8.
And dissabled my DFCO
I left the knock for now
Set the VE_CALC not with DYNAIR_TEMP but with SAE.IAT +2.4 (where 2.4 is typical (ECT-IAT)*bend factor. i.e (80-20)*0.04 which seems about ok only small error <5% vs Charge temp in Kelvin ~290 K ish

Right off for a drive.

Oh and would I expect VE to decrease, such that it will say engine has less air in so put less fuel in. I take it the current VE runs the car rich? Also dont think my LS6 intake has changed the air flow much I thought it would go up? maybe my headers and true dual will change it more if it can evacuate more air, it can get more in :grin:

[WeathermanShawn]

I somehow knew you were smart...:grin:..

Your VE Table will probably shift..I agree the stock VE Tables are overly 'rich' down low. Above 3000+ Rpms, 60 Kpa..you will probably see values increase.

Have fun..Good to have some heavy-duty scientists on board..especially physics..:)..

Later..

[joecar]

Maudy,

Change "5667()" in your calc_pids.txt to read "5.667".

[joecar]

See this: showthread.php?p=118165#post118165 (http://forum.efilive.com/showthread.php?p=118165#post118165)

You will have to populate the lookup() function with values from your own B4901.

[joecar]

haha, thanks for the quick learner comment, im a scientist by day (well just qualified with 1st class degree in physics and now doing a doctorate) :hihi:
...Then you will appreciate this light reading (posts # 103, 104): showthread.php?p=117044#post117044 (http://forum.efilive.com/showthread.php?p=117044#post117044)

That's the basis for this method of calculating the VE...

and then after it's calculated, it is corrected using LTFT's...

and in the same log, the MAF is also corrected (using LTFT's).

[maudyZ28]

Thanks joe, I caught the 5667 bit and changed it. I also did a naughty thing because I didn't know how that look up work, ie just read it now but did a run a few hours ago, so I subbed in IAT + 2.4 for the DYNAIR_TEMP. This is approx right to 5-10K which as a fraction of 290K temp is not much really. The 2.4 is the (ECT-IAT)*blend factor (80-60)*0.04 in this case.

anyway I did a log and it lowered the VE in the low load (low MAP) low Rpms, but i dint get enough high rpm hight load out of PE done. Harder than I though from driving around holding 2nd in my auto.

I applyed it and looked how much the % diff was before and after, and then manually made a VE. I prob shouldn't really but thought I'd give it a go based upon other VE I've seen for similar mods. I reduced it at the low end as the log suggested then ifter if at higt loads all rpm by a few % and at high load high rpm by a few %. I did notice in the log a bit of knock at low rpm high load when running MAF only, so figured that it needs to have more fuel via the VE. You can rip me for this as its against everything but I wanted to see how it went.

0006 tune is the modded one with the VE I made after comparing with the other tune (modded_with2002camarotune) this was from holden crazy for camaro with smae mods + headers and stall and the log data I took. After checking with the log i lowered it ~2% more at low rpm low map, and its ~5% more at high rpm high map

So here they are, i need to do a drive now to check everything, but im thinking a WB is nessasry really

[WeathermanShawn]

I think I know what you did. A little unorthodox, but thats how you learn. So did you use two different High-Octane Spark tables? Looks like a different MAF Calibration Table on the second tune?

My general observation is that you are at the point where a wideband would really accelerate your tuning. Most of your LTFTS (closed-loop) look pretty good. So, I bet most of your tuning will be done via PE Mode..where only a wideband can really do it.

I have found if you are still MAF-enabled a large percent of the airflow calculation for steady state will come from the MAF. Its hard to prove..but we know from 4000 Rpms + on our OS its true. I am just saying that for WOT and PE if you are at steady state you might find more success manipulating the MAF than the VE Table (IMO) as Rpms get above ~3200.

Have fun..

[joecar]

Maudy, remove the parentheses from "5.664()" in your calc_pids.txt.

[maudyZ28]

hi guys, did an epic log the other night, some WOT and mostly driving about. This was the tune and log file along with my PID. I also did a calc VE with STFT and one without FT correction (C and E) maps respectivly

Im i right in thinking if my LTFT are +ve that means the car needs more fuel than its currently getting?

[WeathermanShawn]

Maudy:

I am never sure if you are really following my Tutorial or just doing your own thing. Perhaps it is just my Scan Tool, but I am not getting any of your Calculated PIDS to show up. I guess if I or others are not utilizing them..they don't plot at all.

Anyway, are you 100% sure that you can not log DYNAIRTMP.DMA? I thought for sure your OS allowed that. Secondly I can not vouch for the method of utilizing STFT in lieu of LTFT's. STFT's are very temporal and have wide swings. I did all my testing with LTFT's. Not saying you can not do it with STFT's..but it is an unapproved CALC.VE Table method. I can not vouch for the near 1:1 LTFT to VE % in the CALC.VE Table Tutorial, if one uses STFT's. Again, it may work..but why choose them?

I am not sure what your second statement means..[ my LTFT's are +VE.car needs more fuel..] I am sorry you lost me. Are you using the Tutorial..because then you would see how the MAF and VE interact.

I don't mind 'tutoring' the method I help author..but I am a little confused where you are at in your tune. Where are your wideband AFR's?

As always, it is possible I have misinterpreted your tune and log. But, I don't think you are following the CALC.VE Table method as it is described in the Tutorial.

Perhaps someone can look it over. We may just have some of our fueling/airflow terminology mixed up.. If you need help on the CALC.VE Table Tutorial let me know. If you are using another method, let us know. It will then be easier to guide you..

Regards..

[joecar]

+ve trims means that the PCM is calculating insufficient airmass, and that the PCM then trims the fuel to arrive at stoich.

[maudyZ28]

Shawn, yeah im kinda following the tutorial. I just logged the STFT to compare the difference with LTFT. I will use the LTFT. The map e was just the VE calculated without any BEN correction. Basically for me to see what the MAF was asking for and how far 'off' if was from the corrected VE. I still dont have a WB so using the LTFT correction in your tutorial.

Essentially The tune is the one I use to do the log with an unaltered VE table. I just wanted you guys to check that the logs VE table looked suitable when compared with my standard on. Basically decreased the VE below 3600 rpm with a few increases. The thing that suprised me was at LOW rpm and HIGH MAP was about the same as LOW rpm LOW MAP, so the VE was 'flat' in along the MAP axis at LOW rpm 400-2000 ish. Just wanted a sanity check by you guys. Maybe I can post the changed VE table if you cant read my PIDs

Joecar. Ok so if my trims are +VE it means that the PCM is calculating insufficient airmass from the MAF right, but when compared with the VE table. It WAS NOT exclusively enabled (left enabler at stock 4000rpm) so it should use VE and MAF to do fueling, but no one knows the exact factor split? I wondered where it got the trim from because the calcVE was lower than stock VE table but trims were +ve. I presume this is because im doing it via the MAF calculation method, so my MAF is reading LOW. In closed loop uses MAF for air in and check with O2 and trims are based on these only??? I might just go disable the VE tabe again.

On a final not, most of my driving was steady state at steady throttle, so i'm thinking the MAF is almost always used here not the VE. Again, I seemed to get some knock at 4000 rpm on some full throttle runs, this is on the STOCK tune, why would it be doing this?? I presume now I have the LS6 intake etc that the MAF cannot estimate the right air mass intake at the switch?

I keep confusing myself coming back to it after a few weeks, I wanted to get a tune done before I add my headers and see what the difference was. Still saving for WB :D

thanks again guys



EDIT: ok a +ve LTFT means lean condition, ie too much air. I assume the PCM is using a mix of MAF and VE and the LTFT corrections and calculations are in order the make the 2 match. IT must be using BOTH inputs because it says LTFT +ve so lean or too much air, but the MAF is UNDERESTIMATING and the VE is overestimating. I just hope my LS6 intake in not leaking air in, i think it if was the car would run significantly bad

[WeathermanShawn]

Luke, it sounds like you like to experiment or tinker, which I have no problem with. Its your car, your tune, and your learning curve.

All I can say is that you you will remain very confused about the interaction of the MAF and VE until you apply the LTFTBEN correction against your MAF Calibration Table, B5001. I can say it a million times, but in a MAF-enabled Closed-Loop tune, you will find the MAF drives the majority of the airflow and resultant fueling. You need to tune the MAF first! I have done numerous experiments where I have added and subtracted +/-15 % to the VE Table on a MAF-enabled car..and have seen very little swing in Fuel Trims. Fueling differences have come down to only 'transient'..I.E. only appearing for about 1/2 second, before Commanded Fuel reverts back to the MAF Airflow. This is even for RPM's well below 4000 RPM.

From my perspective, it takes a lot of work to look over tunes and logs. If you look back over the last year of threads, you will see here are less than a half-dozen people who will take the time to look over someones tune and log. So it is more productive on my end to help those who will at least try to apply a solid method.

So, I will politely try one more time. You need to calibrate Table B5001 using LTFTBENS as described in the Tutorial. Don't get obsessed with the VE Table at this point. The MAF Calibration tuning techniques will bring your VE Table in line. Also your LTFT will equalize..which will equalize your STFT's.

I apologize up front if I am a little irritated. It may be a case where 'smart' people are just harder to teach. But, it is frustrating to see someone confuse themselves..and then admit they ['are kinda following your Tutorial'.]

Please calibrate your MAF..You will be very pleased. Also, remember I am emphatic about the use of a wideband. You can not touch PE until you get one. If you blow up your engine, its not my fault. You need one to tune. New engines cost ~8,000. A wideband is ~300.00.

Drive safely. If someone else wants to guide you along, they are more than welcome. I am here to help..but it has to be a two-way street.

Thanks for understanding..:cheers:

[maudyZ28]

thanks Shawn,

yeah i'm prob harder to teach, i try to over analyze everything before I try it, then I try to do it all at once.

Im going to apply the LTFT to my MAF, the log got all freqs upto where I pressed the throttle too much and went PE (but removed these from the log in a filter). The LTFT here are saying the MAF is reading low as the trims are all above 1. Im also going to apply the calcVE in the area in the VE table for consistency (as your tutorial). I cant go on another log with this set up as im putting my header on tonight so will do another log etc after.

I think you answered what i was confused with, ie most trims come from MAF as you say you have experimented with little change if you adjust the VE :)

I was only bothered about the VE saying that at low rpm the table was flat for all MAPs, ill post what i mean tonight when im home.

One last question, is it normal for a MAF to under read, or is it due to my set-up with LID and air filter? ie the car getting more air than the MAF thinks (hope there is not a hole in my LS6 intake???? :( ) Will the car drive any different after I have applied the LTFT, and also would you smooth them or literally just apply them.

Also im not going to do any PE, i just wondered why it was getting knock on the stock setup at 4000 rpm, seems to be coincidence with the MAF switch over that's all? maybe due to the a fore mentioned under reading ^^^

Thanks for the patience :D, i wouldn't be asking so much if I had the WB as a verification tool, i just want to make sure i dont bust anything as this method means I cannot check anything yet :cheers:

[joecar]

If the MAF is under-reading, then the PCM is calculating a smaller load which indexes higher spark timing, which is maybe why you get knock.

Everything interacts with everything else, it's all very dynamic.

The VE table only comes into it during transitions in airflow and/or throttle under 4000 rpm... the idea is that the MAF response to a transition is delayed a little.

[WeathermanShawn]

thanks Shawn,

yeah i'm prob harder to teach, i try to over analyze everything before I try it, then I try to do it all at once.

No, I understand. Occasionally I have fallen victim to the same mindset..

Im going to apply the LTFT to my MAF, the log got all freqs upto where I pressed the throttle too much and went PE (but removed these from the log in a filter). The LTFT here are saying the MAF is reading low as the trims are all above 1. Im also going to apply the calcVE in the area in the VE table for consistency (as your tutorial). I cant go on another log with this set up as im putting my header on tonight so will do another log etc after.

You have the concept. It will be interesting to see how the headers change your airflow (MAF, LTFT, and ultimately VE)..

I think you answered what i was confused with, ie most trims come from MAF as you say you have experimented with little change if you adjust the VE :)

Yes, it an anecdotal observation. I see it in my logs..It would take a lot of math and understanding computer code to prove it to a 100% scientific validation..

I was only bothered about the VE saying that at low rpm the table was flat for all MAPs, ill post what i mean tonight when im home.

Thats sounds odd. We will see how it looks the next time..

One last question, is it normal for a MAF to under read, or is it due to my set-up with LID and air filter? ie the car getting more air than the MAF thinks (hope there is not a hole in my LS6 intake???? :( ) Will the car drive any different after I have applied the LTFT, and also would you smooth them or literally just apply them.

Yes, it is normal for the MAF to under report airflow with a lid. Probably harmonics are also involved, but 'normal'. Yes, a car will drive different if the fueling becomes correct. Less bucking, smoother decelerations, responsive throttle when WOT. It also takes correct spark, NO KR etc..but a car that does not undergo massive trimming runs smoother (IMO).

Also im not going to do any PE, i just wondered why it was getting knock on the stock setup at 4000 rpm, seems to be coincidence with the MAF switch over that's all? maybe due to the a fore mentioned under reading ^^^

Joecar's explanation is right on!

Thanks for the patience :D, i wouldn't be asking so much if I had the WB as a verification tool, i just want to make sure i dont bust anything as this metho:grin:d means I cannot check anything yet :cheers:..
Well, you can do a lot of the non-PE tuning. You can tune the bottom half of the MAF curve (non-PE). With headers, lid, and running +LTFTS, you run the risk of being lean at WOT. Any KR of over 4 degrees for 10 seconds or more..is asking for a burnt piston. Stay out of KR, lower your spark, keep your knock sensors at stock settings, keep Adaptive Spark working..and order a wideband..:grin:



Good Luck..

[maudyZ28]

thanks again guys, edited and stock tunes below :)

changed the MAF and the VE, i smoothed the VE by two clicks in the lower regions

oh, i also check back to a log before the LS6 intake where I had some LTFT listed, i was on average -8.0 , dated below, and the new one was -0.5 with the LS6, big difference, good or not?? :shock: (saying that I was doing this log correctly with DEFO off) im quite worried about the MAF reading low on WOT, would it be bad just to bump it all up a little bit at the top where I haven recorded to MAF freqs by about the same as at low rpm, after 4500 hz the multiplicative BEN FACTOR is ~1.05

anyways, im on with the headers, got all the other stock stuff off, lost a bit of skin on the fingers but ill live :)

[WeathermanShawn]

Luke, as far as the MAF Frequencies above 4500 Hz..It is kinda of a guess without a wideband..but in general MAF frequencies tend to follow the same slope. I.E. if you have had to add 5-10% below 4500 Hz, its not unreasonable to have add the same correction percentages above. But, big disclaimer..its a guess..

Like I said, I can not vouch for CALC.VE Table constructed without the DYNAIRTMP.DMA PID. I am not that confident in the interpolative ability of the look-up factor. The CALC.VE Table needs an instantaneous DYNAIRTMP to be accurate. If it is off, all your work will be off. Again, I am very surprised you do not have that Pid.

Thats about all I can for you at this point. Be very careful about overly smoothing the VE Table. Remember, (from the Tutorial) your CYLAIR and DYNCYLAIR must be very close at all RPM's and MAP's. If you smooth too much..you have defeated the purpose of modeling airflow..

Enjoy those headers..Headers are fun!!!

[maudyZ28]

cheers Shawn,

im gonna multiply by a factor of 1.04 just to be on safe side with headers etc, if anything it will run rich and my LTFT will be -ve then. OK I know what you mean about lookup, it may take some time so may be off, i dont know why i dont have the PID?? 99 OS ??

with the headers, i did notice last night that the o2 sensors do not stick out into the flow of the exhaust as much as they did stock, is this a purposeful design feature so the o2 read leaner and thus eventually trims are adjusted such that the car runs a little richer with headers to be on the safe side.

Man I want a wide band, but gotta pay back £700 for the efi live yet :(

[WeathermanShawn]

Man I want a wide band, but gotta pay back £700 for the efi live yet :(

Cheers Luke:

I have taken you as far as I can with the tutoring. You have done most of the stoich portion of the tune, and I think you have the concept down.

For PE you need a wideband. I can not responsibly participate in tutoring if the student can not or will not purchase the necessary tools. You would probably tell your students the same thing if they showed up to class with no books or calculators.
I wish you luck. Drive safely, and when you are ready to complete the CALC.VE Table method of tuning, let me know..:cheers:..