Yes, thanks to all who have contributed their experiments results, and to all who have explained to me the fine points. :cheers:
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Yes, thanks to all who have contributed their experiments results, and to all who have explained to me the fine points. :cheers:
Hi Joecar,
I am only new to tuning and this summary post is great. You have answered a truck load of questions I had. Thank you very much!
No worries, thanks for the feedback, this thread is meeting its intended function :cheers:
Updated the calc_pids.txt file in post #2, added a pid for calculating cylinder airmass from GM.VETABLE_DMA.
calc_pids.txt
Hey Joel, how's it going :cheers:
Thanks, any comments from you guys are welcome... I'm hoping to tidy it up a little, and possibly add spark timing relationships;.
I'll add links in the other subforums to this thread.
SOL (semi-open loop)
enabled via:
- OS: B4206
- COS: always enabled
if enabled, SOL is active only during OL;
SOL uses STFT to trim to stoich cells in B3605 or B3647;
for non-stoich cells in B3605 or B3647 SOL does not trim;
if PE enables while SOL trimming, if PE is richer then stoich, you will see PE fueling (i.e. the richer of the active tables);
SOL can function only if trimming to stoich is possible, otherwise it won't function.
Quoted from this thread: Calculating-Injector-Flow-rate
Marcin's injector flowrate spreadsheet is attached to this post (scroll to bottom of post).
Quote:
The math behind this is as follows (for those who want to know)...
Definitions
R0 = injector's rated flowrate measured at pressure P0
P0 = pressure at which the injector's rated flowrate R0 was measured (see Note below)
FP = regulator's gauge pressure, also known as regulator's base pressure.
MAP = manifold absolute pressure
BARO = barometric absolute pressure = 101.3 kPa at sea level = 100 kPa approx. a little above sea level
MANVAC = manifold vacuum = BARO - MAP
gauge pressure = absolute pressure - BARO = value shown by pressure gauge
absolute pressure = gauge pressure + BARO
Pressure difference across an injector: this is the difference in the absolute pressures above and below the injector.
An unreferenced regulator has its pressure set constant; this pressure is FP (gauge) or FP + BARO (absolute).
A MAP-referenced regulator has a reference hose connected to the intake manifold,
so its pressure has MAP added to it; this pressure is FP + MAP (gauge) or FP + BARO + MAP (absolute);
with reference hose removed, this pressure becomes FP + BARO (guage) or FP + BARO + BARO (absolute).
The flowrate of an injector is directly proportional to the squareroot of the pressure difference across the injector (this is the Bernoulli pressure relationship).
Note on Injector Flowrate Measurement:
when R0 is measured on an injector flow bench, P0 is actually the pressure difference across the injector:
absolute pressure above injector = P0 + BARO; absolute pressure below injector = BARO; so then difference = P0.
Note regarding 1997-1998 Y-car:
The FPR is not MAP-referenced (follow the reference hose to verify it sees atmosphere/BARO).
Unreferenced Regulator (e.g. 1998-2002 F-car, 1997+ Y-car)
Pressure difference (of absolute pressures) across injector = (FP + BARO) - (MAP) = FP + BARO - MAP = FP + MANVAC
IFR = R0 * sqrt((FP + MANVAC) / P0) = varies/slopes with MANVAC
At the rail, absolute pressure is FP + BARO, so gauge pressure is FP.
--> Directly measure FP at rail with engine running (FP should be constant).
The spreadsheet calculates this equation (Example 1, post #3).
MAP-Referenced Regulator (e.g. trucks)
Pressure difference (of absolute pressures) across injector = (FP + BARO + MAP) - (MAP) = FP + BARO
IFR = R0 * sqrt((FP + BARO) / P0) = constant/flat regardless of MANVAC
At the rail, absolute pressure is FP + BARO + MAP, so gauge pressure is FP + MAP.
Remove reference hose, regulator is now exposed to barometric pressure (so MAP = BARO),
and rail absolute pressure is FP + BARO + BARO, so gauge pressure is FP + BARO.
--> With reference hose removed, directly measure FP + BARO at rail with engine running.
The spreadsheet calculates this equation at MANVAC=0 if measured FP + BARO is entered (Example 2, post #3).
Units
Rail pressure is measured in psi, and MAP or MANVAC is measured in kPa.
You need to convert one to the units of the other before calculating IFR.
Convert psi to kPa by multiplying by (100/14.5).
14.5 psi = 100 kPa
If injectors are rated in lb/hr:
convert lb/hr to g/s by multiplying by 0.125998 (can round to 0.1260).
1 lb/hr = 0.1260 g/s
If injectors are rated in cc/min:
convert cc/min to g/min by first multiplying by density of gasoline (typically 0.73 g/cc), and then dividing by 60.
1 cc/min = 0.0122 g/s (depending on density of gasoline)
I have now read through and researched these summary notes probably ten plus times in the past several months and now I consider them to be akin to the Rosetta Stone for the LS1B PCMs. At least as far as using EFILive Scan and Tune the Powertrain Control Module.
So for anyone who is a new or even seasoned tuner, I'll say don't give up if all of this seems complicated, etc. It is complicated, but it can be so very rewarding for those who want to modify their engines, make their transmissions (automatics) shift differently, etc. This is great stuff!
Steve
joecar, this is great stuff...is there any way you/someone could convert the param/table numbers to current numbers since some of these were merged or renumbered.
Thanks