some questions on calc.vet

[joecar]

...

this has me confused. If the VE is disabled, how does the BEN reflect the VE table? Doesn’t it reflect only the MAF correction, then calculates the proper VE table?

Sorry, I meant MAF.

And afterwards you will want to disable MAF and see how VE performs.

If I understand you correctly I should watch SELBEN factor on a WOT pull to 4500…. The goal is to have it within .02 of 1.00. but im unsure of what this would be telling me other than that the MAF is where it should be

If you get LTFT's close to zero, then at WOT/PE the residual LTFT will not contribute to fueling (it will be zero) so the correction will be from wideband only.

I must not understand something fundamental in this process.. I am running with ve disabled above 400 rpm so I am assuming that the MAF can only be the contributor.

You are correct (I mistyped above, I should have said MAF instead of VE... (( would you believe I was testing you ))

What do I look for in the logs to determine if this is a problem?

When you look at GM.DYNAIR and SAE.MAF, hopefully they converge.
Same with GM.DYNCYLAIR and CALC.CYLAIR.
SELBEN should be close to 1.
CALC.VET and CALC.VEN should be the same.

Also when done with CALC.VET, disable the MAF, disable CL/LTFT/STFT and use wideband only to see how the VE performs.

[estringer]

Joe,

I am running a 98 ECU/car so I do not have GM.DYNAIR..

Also I do not have GM.DYNCYLAIR selected, Nor do I have CALC.CYLAIR in my logs... all I have is GM.CYLAIR_DMA. is this all a product of having a 98 ECU?

Selben is running +/- .02 almost everywhere which seems good

lastly, watching calc.vet and calc.ven they are typically within .02 of each other at 98% of the time.... on rare occasion they are off by as much as .08-.1 g/kpa

are these acceptable tolerances?

[joecar]

Ah, ok, 1998 (LS1A in EFILive terminology), yes some pids are not available.

If you logged SAE.MAF and SAE.RPM, then CALC.CYLAIR can be added after the log is captured
(while viewing log, goto PIDs tab, click (once or twice) on the column heading Parameter to sort it alphabetically, find CALC.CYLAIR and select it)


Yes, those are quite acceptable.

Questions:
- how is throttle response compared to before...?
- how is driveability...?
- what other improvements do you see...?
- what do you think of the Calc.VET procedure...?

Thanks, I appreciate you taking the time to do Calc.VET and providing me feedback.

[estringer]

Joecar- thanks for all your help on this. I have yet to run speed density to verify the ve table so I cannot comment yet on feedback for calc.vet until I am done with the tuning, but I most certainly will once I do that. It's the least I can do for all your help. Also, in my other thread (sanity check ve table) you requested I post my tune, I would greatly appreciate you looking at it and will do so hopefully tomorrow. I am an on call worker and am on my way out the door as we speak and have barely had the time to eat sleep and the other thing...

[joecar]

No worries, take your time.

[estringer]

Also I ordered a screened Delphi 85mm maf and the bits to go with it on a whim just in case my descreened stock maf was causing a problem...
Is it worth Installing this on a ~500 rwhp car and

I know the maf table will need to be redone however will the ve table drastically change? Or would the new ve table valuea effectively show the gain/loss from a new maf

[joecar]

The screened MAF will not restrict air (not to 500 rwhp).

It may improve driveability.

VE calculation may reflect improvement due to MAF.

We'll see...

[estringer]

okay, so ive finally gotten a break here...

Questions:
- how is throttle response compared to before...?
- how is driveability...?
- what other improvements do you see...?
- what do you think of the Calc.VET procedure...?

throttle response has not seemed to change much. as of this point I have not reenabled the VE table or checked it by failing the MAF. however just by correcting the MAF curve I have found that it SEEMS to run smoother and start up smoother with less idle hunting than before. it may be in my head. also, I am running a spark table that came with my base tune from vengeance that has not produced knock and has more timing down low.

driveability has improved, the car feels smoother all around at this point even with the VE table disabled

AFR at WOT has gone from 11:1 to 12.5-13.0:1 just by correction of the MAF and seems to be pretty consistant.

once I determined that I could watch the table section of efi live scan and determine what cells I'm hitting while driving, I was able to create much better logs

also once I had it in my head clearly that calc.ve creates a CORRECTION FACTOR for the MAF and a REPLACEMENT TABLE for the VE table, I also was able to understand that the correction factor for MAF can be applied only once and if reapplied will skew the MAF table incorrectly whereas the VE table data can be stacked on top of each other from multiple logs until a consistent VE table pattern is showing before I do any smoothing, etc.

I am also unsure of how to tune PE mode... do I do this by modifying the b3618 PE modifier value

i am still fairly uncertain of my work on the VE table... but my concerns cant be substantiated until I reenable the VE table

I will most definitely post a thorough feedback thread once the process is completely done and I can evaluate from a finished product standpoint. I see a lot of posts that ask questions and work through problems but very little in the form of completed tune thoughts.... the people just dissapear

[joecar]

throttle response has not seemed to change much. as of this point I have not reenabled the VE table or checked it by failing the MAF. however just by correcting the MAF curve I have found that it SEEMS to run smoother and start up smoother with less idle hunting than before. it may be in my head. also, I am running a spark table that came with my base tune from vengeance that has not produced knock and has more timing down low.

When you slam throttle open, does soon does engine respond...?

I am also unsure of how to tune PE mode... do I do this by modifying the b3618 PE modifier value

PE and spark are best tuned together on dyno...
you increase spark until you see no appreciable gain in TQ (with no knock) and then you back this off;
you reduce EQR (go leaner) until you see increase in HP (with no knock);
you do then repeat both of those a few times, each time making sure you get no knock.

when dyno time is not avaiable, you set spark close to stock, set PE to safe (NA EQR 1.175, TC/SC EQR 1.28).

And, either way, whenever you drive, you always pay attention to listen for knock (I now do this on any car I drive, tuned or stock).

i am still fairly uncertain of my work on the VE table... but my concerns cant be substantiated until I reenable the VE table

At some point, you will do the opposite of Calc.VET as a sanity check:
you will disable the MAF (a DTC is required to immediately appear), you log, and you compare VE table to BEN, and see if it's close.

I will most definitely post a thorough feedback thread once the process is completely done and I can evaluate from a finished product standpoint. I see a lot of posts that ask questions and work through problems but very little in the form of completed tune thoughts.... the people just dissapear

I know, stuff happens...

and the other thing that makes writing this up difficult incorporating new ideas/methods are found as time goes on (for example, now, with 2 widebands, we have can chose the leanest wideband on-the-fly and use that for the BEN calculation... i.e. this allows MAF and/or VE to be tuned for the leanest bank... I have calc_pids.txt file for this (see attched), and now I have to figure out how to write this into the procedure).