Tuning Calc. Load max on NA engine
10-15-2011, 07:34 PM
#76
You may end up with negative results as a result of other conditions and maps
As an example, a turbo will see much higher IATs than NA, you can counter the negative impact on load, which further impacts timing map load point selections etc by altering the IAT load map
There are a whole series of maps and their cell inputs that determine the final output value
As an example, a turbo will see much higher IATs than NA, you can counter the negative impact on load, which further impacts timing map load point selections etc by altering the IAT load map
There are a whole series of maps and their cell inputs that determine the final output value
10-15-2011, 08:12 PM
#77
10-15-2011, 08:38 PM
#78
Let me ask one last question of MM...
If i were to set the fuel table up so that there were columns for say 250% load ,would the ECU ever be able to reference those numbers for its fuelling calculation?
Assuming all comp. multiplier tables were set to 1 (eg , IAT and baro)
A simple yes or no answer will do ......
If i were to set the fuel table up so that there were columns for say 250% load ,would the ECU ever be able to reference those numbers for its fuelling calculation?
Assuming all comp. multiplier tables were set to 1 (eg , IAT and baro)
A simple yes or no answer will do ......
Last edited by Brettus; 10-15-2011 at 08:47 PM.
10-15-2011, 10:35 PM
#79
Release the twins.
without using the wrong terms....
What you want to accomplish is.
97.5 percent CalcLOAD should equal about 50 percent ACTUAL load.
And 195 Calc load, should be the MAX ACTUAL load. because you've setup your tune in away that you can't go over 195, you can't go measuring off your ruler, because you've stretched your ruler just long enough to cover the range you're going to run.
your 100 percent load, may be at 2 or 3 psi, depending on a particular setup.
IF you then say, change out turbos, and your engine puts out higher FLOW/power, You would want to/have to retune, and restretch your ruler so that your new setup is in the range of your tune...
Thats how i see it at least.
What you want to accomplish is.
97.5 percent CalcLOAD should equal about 50 percent ACTUAL load.
And 195 Calc load, should be the MAX ACTUAL load. because you've setup your tune in away that you can't go over 195, you can't go measuring off your ruler, because you've stretched your ruler just long enough to cover the range you're going to run.
your 100 percent load, may be at 2 or 3 psi, depending on a particular setup.
IF you then say, change out turbos, and your engine puts out higher FLOW/power, You would want to/have to retune, and restretch your ruler so that your new setup is in the range of your tune...
Thats how i see it at least.
10-16-2011, 01:06 AM
#80
Hmmmmmm.........
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10-16-2011, 02:16 PM
#86
Remember - the L3-VDT (MZR Turbo) has torque targets as part of the programming. This is a variation on how the Subies are programmed.
The MSP does NOT have this because the PCM is an NA application.
10-16-2011, 03:05 PM
#88
This is a critical parameter for higher HP applications due to the fact that the ECU is not able to properly calculate fuel requirements when demand exceeds the load cap. If the load cap is set too low, a lean condition occurs, getting worse as the delta of actual load goes further beyond the load cap.
MMMMMMMM
MMMMMMMM
10-16-2011, 03:10 PM
#89
This is a critical parameter for higher HP applications due to the fact that the ECU is not able to properly calculate fuel requirements when demand exceeds the load cap. If the load cap is set too low, a lean condition occurs, getting worse as the delta of actual load goes further beyond the load cap.
That makes it, for our purposes, a better PCM for FI than the L3-VDT (MZR Turbo) PCM for this very reason. It has no inherent, mathematical cap to the AbsLOAD calculation (up to the end of the MAF limit).
The PCM will "run off the edge of the map" since it has no constraints.
This is why I am trying to get you guys to wrap your head around the "CalcLOAD limiter" problem rather than just giving some single-sentence answer that, ultimately, wouldn't be an answer as soon as something else changed in the calibration.
10-16-2011, 04:42 PM
#93
If it is too small,you simply don't get to see the rest of the information and the resulting "error" is reported as a hole in the tuning, even though the information still exists.
If it is too big, the information is written in bigger letters to fill the page.
The page always must be completely filled to get reports that conform to the actual data.
If it is too big, the information is written in bigger letters to fill the page.
The page always must be completely filled to get reports that conform to the actual data.
10-19-2011, 09:30 PM
#97
Hmmmmmm.........
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So can someone tell me if this is the correct formula for Calculated load:
Calculated Load = [current airflow] / [(peak airflow at WOT@STP as a function of rpm) * (BARO/29.92) * SQRT(298/(AAT+273))]
STP = Standard Temperature and Pressure = 25 °C, 29.92 in Hg BARO
SQRT = square root
WOT = wide open throttle
AAT = Ambient Air Temperature and is in °C
If this IS correct then then there are 2 variables other than those listed above. The first is "current airflow" and I assume is the reading from the MAF, but the second "peak airflow at WOT@STP as a function of rpm", where does this come from? Surely its a table somewhere?
Cheers
Andrew
Calculated Load = [current airflow] / [(peak airflow at WOT@STP as a function of rpm) * (BARO/29.92) * SQRT(298/(AAT+273))]
STP = Standard Temperature and Pressure = 25 °C, 29.92 in Hg BARO
SQRT = square root
WOT = wide open throttle
AAT = Ambient Air Temperature and is in °C
If this IS correct then then there are 2 variables other than those listed above. The first is "current airflow" and I assume is the reading from the MAF, but the second "peak airflow at WOT@STP as a function of rpm", where does this come from? Surely its a table somewhere?
Cheers
Andrew
10-20-2011, 12:24 PM
#98
Had a cold front come through and I rocketed right through the roof on my NA load table. The tune went lean in some areas, others not. Not sure why, so I'm building a different tune to test out some ideas on alternate configuration methods.
