A few ??'s, VE, PE, IFR
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A few ??'s, VE, PE, IFR I have done tons of reading on tuning recently and have ls1 edit/scanner now. I read that VE tuning is pointless since the VE tables are almost never used, is this correct? And if you havent messed with the MAF as in aftermarket/ported/descreened then there is no need to mess with the MAF table?? I also read that all closed loop fuel tuning can be done via the fuel injectors, right or wrong? Then once you have the injectors on point and have the LTFT's zero or slightly negative you can move on to WOT tuning. Am I on track here or am I just lost? Bare with me Im kinda new at this. Also, is it normal for the O2 sensors (narrowband) to dip down to like 150mv cause mine do when I logged?
OK, let's dissect this....
In closed loop, VE is used mainly during airflow transitions. MAF is dominant in steady state conditions, and above 4000 RPMs.
If airflow hasn't changed (cams, cold air intake, etc.) then MAF should be OK.
Many ways to skin a cat. To increase/decrease AFRs, you typically change air or fuel. Most people adjust MAF and VE (Air)....there seems to be more resolution in those tables than the fuel tables. Don't know if there's a 100% text book correct way to do it.
Yes. O2s cycle (dip) during normal operation so the PCM can be sure they are working.
Originally Posted by brad8266
I read that VE tuning is pointless since the VE tables are almost never used, is this correct?
Originally Posted by brad8266
if you havent messed with the MAF as in aftermarket/ported/descreened then there is no need to mess with the MAF table??
Originally Posted by brad8266
I also read that all closed loop fuel tuning can be done via the fuel injectors
Originally Posted by brad8266
Also, is it normal for the O2 sensors (narrowband) to dip down to like 150mv cause mine do when I logged?
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Originally Posted by muncie21
OK, let's dissect this....
If airflow hasn't changed (cams, cold air intake, etc.) then MAF should be OK.
If airflow hasn't changed (cams, cold air intake, etc.) then MAF should be OK.
Originally Posted by brad8266
I thought MAF table was just calibration for the MAF unit itself, so if it is still stock and not ported or any of that there is no reason to mess with MAF tables even with mods like intake, cam.
An example is a large cam, which can cause an inversion of air (reversal) during idle. The MAF will see this, but it doesn't know which way the air is going
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Originally Posted by muncie21
Basically you are correct. However, anything that changes how air gets into or out of the motor can affect the MAF.
An example is a large cam, which can cause an inversion of air (reversal) during idle. The MAF will see this, but it doesn't know which way the air is going
An example is a large cam, which can cause an inversion of air (reversal) during idle. The MAF will see this, but it doesn't know which way the air is going
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Originally Posted by brad8266
OK I see what you mean by the big cam, but is there really any need to tune MAF is you have only intake and few other boltons?
GM spent lots of time making a stock calibration that would be safe under many different situations... but safe != power....
After messing with MAF and VE I'm trying now to use just the IFR and it works.
I log for LTFT, STFT and MAP
I average LTFT and STFT, put the results included MAP values in a pivot table (excel) and so I can figure out a new IFR curve.
It's not a straight line as in the original table, it has a couple of bumps.
So far (in my case) the best result ever.
I log for LTFT, STFT and MAP
I average LTFT and STFT, put the results included MAP values in a pivot table (excel) and so I can figure out a new IFR curve.
It's not a straight line as in the original table, it has a couple of bumps.
So far (in my case) the best result ever.
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On The Tree
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i would like to know where to get the gms air/cyl amount used in the spark tables. LS1 scan is a BS crappy scan tool and does not give us this value. And my OBD-2.com scan tool doesnt either, eventho its listed as a enhanced data line in the ybody bin file. I emailed customer service and have gotten no response. Quite frankly Im ready to return my LS1_edit and order HP Tuners because of this MAJOR issue.
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Verdad Gallardo G/Cyl = 15 * MAF / RPM
Maf in G/sec (if your MAF is correct)
Edit is not too bad, it just needs you to calculate the tables by yourself.
Excel is a good tool for that, but you know what you are doing.
I don't know OBD-2.com, I use Atap (antiquate but still fine - at least for my needs)
Maf in G/sec (if your MAF is correct)
Edit is not too bad, it just needs you to calculate the tables by yourself.
Excel is a good tool for that, but you know what you are doing.
I don't know OBD-2.com, I use Atap (antiquate but still fine - at least for my needs)
On The Tree
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well now that i have the missing piece of the puzzle im happy.
I didnt know about the formula i needed to use. Not sure I need the excel file, but wouldnt mind taking a look at one somebody made already. I guess I could always make my own.
tici, thankyou for the info. now I can tune!
I didnt know about the formula i needed to use. Not sure I need the excel file, but wouldnt mind taking a look at one somebody made already. I guess I could always make my own.
tici, thankyou for the info. now I can tune!
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Tuning your WOT open loop fueling by messing with the IFR is a shocking way of tuning. Yes it works, but so does wiping your **** with your hand.
IFR is a fixed table based on injector flow, nothing else. You set it irrespective of engine or modifications. Its the VE table that maps out the efficiency of the engine and hence how much fuel should be injected at each load point, thats why you should tune VE.
If you do anything else you are tuning with the aliens.
IFR is a fixed table based on injector flow, nothing else. You set it irrespective of engine or modifications. Its the VE table that maps out the efficiency of the engine and hence how much fuel should be injected at each load point, thats why you should tune VE.
If you do anything else you are tuning with the aliens.