Calan
DSM Wiseman
- 7,250
- 398
- Jan 16, 2007
-
OKC,
Oklahoma
Now that I think about it, here's something else worth mentioning about open-loop calibration...
The guys over at ECMLink wrote some fairly complex algorithms for the closed-loop MAFComp and VE adjust tools to determine what is good data and what isn't. When using the WBError in open loop to do it manually, you have to decide for yourself what is valid data and what isn't.
During open loop at WOT, it's easy; throttle is 100%, while RPM and load is increasing at a nice linear rate. So other than that first little section when things are settling down, the entire pull is good stable data.
While cruising in open loop though, that isn't the case. You are constantly varying the throttle and RPM, and engine load changes with hills, wind, etc. (Not to mention the desired AFR is a moving target instead of 14.7:1, unless you set large areas of the DA table to the same AFR value). So you have to hold conditions stable at different points to get good steady-state data to use, or look for sections in the log where those conditions are met.
The best way to go about that I've found is to find a flat stretch of road and hold the throttle and RPM at a set point (say 3000rpms) for 10-15 secs, while making sure LoadFactor doesn't vary too much. Then highlight the middle 3/4 of that section or so, average it, and adjust airflow based on that. If you can do this safely in different gears and at different speeds/load/RPMs, you can cover quite a bit of the operating range and get pretty solid numbers to work with.
If you are really anal you can try holding MAFRaw at a specific value that corresponds to a slider. For the VE guys, you can try holding things at a point that corresponds to a specific RPM/MAP cell in the VE table.
Tip: Long, steady hills are great for getting to higher airflow/load points at lower RPMS and safe speeds. If you have aftermarket brakes and know what you are doing, you can also carefully drag the brake pedal for short periods of time to increase load...but I didn't tell you that.
The guys over at ECMLink wrote some fairly complex algorithms for the closed-loop MAFComp and VE adjust tools to determine what is good data and what isn't. When using the WBError in open loop to do it manually, you have to decide for yourself what is valid data and what isn't.
During open loop at WOT, it's easy; throttle is 100%, while RPM and load is increasing at a nice linear rate. So other than that first little section when things are settling down, the entire pull is good stable data.
While cruising in open loop though, that isn't the case. You are constantly varying the throttle and RPM, and engine load changes with hills, wind, etc. (Not to mention the desired AFR is a moving target instead of 14.7:1, unless you set large areas of the DA table to the same AFR value). So you have to hold conditions stable at different points to get good steady-state data to use, or look for sections in the log where those conditions are met.
The best way to go about that I've found is to find a flat stretch of road and hold the throttle and RPM at a set point (say 3000rpms) for 10-15 secs, while making sure LoadFactor doesn't vary too much. Then highlight the middle 3/4 of that section or so, average it, and adjust airflow based on that. If you can do this safely in different gears and at different speeds/load/RPMs, you can cover quite a bit of the operating range and get pretty solid numbers to work with.
If you are really anal you can try holding MAFRaw at a specific value that corresponds to a slider. For the VE guys, you can try holding things at a point that corresponds to a specific RPM/MAP cell in the VE table.
Tip: Long, steady hills are great for getting to higher airflow/load points at lower RPMS and safe speeds. If you have aftermarket brakes and know what you are doing, you can also carefully drag the brake pedal for short periods of time to increase load...but I didn't tell you that.
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