There is a very good explanation of the various forms of "VE" (used very loosely) on redhardsupra's blog site. Don't think of the VE as only volumetric efficiency. It has several other forms and units. I still haven't made complete sense of the tables we currently have, but I will continue to work on it.
I still say the VE tables are not arbitrary or the open-loop fueling would be way off (if you use the % maximum value). I can change the PE AFR and see it reflected in the wideband reading. There are several places where the commanded and actual are not as close as I would like them.
I checked a log file. My calculated load ranges from 0 to 100%, my throttle position ranges from 4.7 to 100%. Here's the interesting thing: any throttle position over 31.5% shows 100% load. Throttle opening influences VE, but according to the table in EFILive referenced by the PCM, I can't increase VE for any throttle position above 31.5%. This can't be true because the throttle has much more opening to do and VE could go much higher. If I'm roughly open a third of the way, there is at least twice as much area left to open. My VE would likely double and be well over 200%...Those numbers are just for reference because there are many different gains in the system that we can't see.
I would agree that throttle opening (ie MAP) influences VE. I am not completely sure that the column headers (or the calculated load% PID) are correct in our VE tables. What are the values of MAP and BARO when the %load first hits 100? Are you logging APP, TP, or ETC?
Why would you think your VE would double by opening the throttle plate ~66% more? The mass flow will increase if you are not already at BARO pressure behind the throttle body, but the efficiency would not double. The efficiency is the ability to completely fill the chamber with "actual" air mass (taking pressure and temperature into account).
Can you post one of your log files that show the 8 degrees of KR from 1400 to redline?
If the throttle area increases linearly (it really doesn't), the increase is not 66% when going from 31.5% to 100%, it's 217%. My PID's are listed in a previous post. Our barometric presure is around 101 kpa here and the MAP sensor reads around 70kpa when I hit 100% load. I've attached a really old log file. I won't run that tune anymore so I won't gather new data with my current PID's.
Wow, that file has alot of PIDs slowing it down. 33 PIDs using 37 channels and updating at ~1 fps? I assume this was one of the first logs. I saw a little burst knock, but not anything like what you had described. This log file doesn't even go above 2700 Rpm or 57% TP.
The calculated load percentage value uses current airflow/peak airflow and corrects to STP. I have no idea where the airflow numbers are coming from. None of them make any sense. I would think that the %load would be based on MAP/BARO.
I have very few logs saved from running that tune. I've deleted most anyway since the tune was so bad and I only used it for about a week. I now run the PID's listed earlier which run at a significantly higher rate.
Just out of curiosity... the LL8 profiles list two octane tables. What would make the I6 program switch from one to the other? We don't have less than 87 here, and we top out at 93. So would there be any benefit to switching by default to the high-octane table?
I too am new to this and am trying to get a feel for what is "normal and acceptible" before I start digging into tweaks. I am seeing quite a bit of knock-related activity with my stock tune on 87octane gas and would like to know if it's reasonable or potentially a problem exists.
*bump*
Come-on, I know someone has glanced at this KR trend and thought either:
a) looks normal to me...
b) wow that's some knock! there's something wrong going on (bad gas etc...)
c) looks like maybe the data trend is wrong... (did something such as conflicting channels being trended mess up the scaling?)
If you don't mind sharing your input, I'd love your help! Thanks!
Try these things:
- 91 octane gas (you live in CA);
- clean the MAF sensor (use only CRC "MAF Cleaner" or CRC "QD Electronic Cleaner"... do not use "Electrical" cleaner or "Brake" clean);
- check to see if oil is being pulled into intake via PCV valve;
- are your spark plugs in good condition;
- is engine coolant temp. overheating (is ECT sensor reading right);
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