Elusive fuel
#44
I mean if he's gonna claim that the stock fuel system can go beyond the injector duty cycle limits because the pump is strong, and that you can keep going with injectors never closing until you run out of fuel pressure, I think I would have to agree with that. At least based on what they've provem already with the AO kit.
Most of us would agree that is very dangerous, but appears possible.
Most of us would agree that is very dangerous, but appears possible.
#48
and it's not 60psi flat on an nb returnless system. but that doesn't matter, because BEGi already proved that its still possible, even with a tapering rail pressure.
#51
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omfg, this thread is painful to read.
Someone with a Dynojet plot of their car and a datalog of a WOT pull please post the following four traces on the same plot:
1. horsepower (SAE corrected)
2. torque (SAE corrected)
3. ECU-commanded pulsewidth
4. ECU-calculated injector duty cycle
Someone with a Dynojet plot of their car and a datalog of a WOT pull please post the following four traces on the same plot:
1. horsepower (SAE corrected)
2. torque (SAE corrected)
3. ECU-commanded pulsewidth
4. ECU-calculated injector duty cycle
#52
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BTW, before that chart is posted, here's what I think it will show:
-injector pulsewidth correlates to torque, but not as closely as Corky thinks
-injector duty cycle correlates to power, but not as closely as anyone thinks
-both of these are true because BSFC (fuel mass required to make X horsepower for X hours) goes up as engine speed increases
Here's a cool chart to show why this is true:
3OugEDm.png
[/thread]
-injector pulsewidth correlates to torque, but not as closely as Corky thinks
-injector duty cycle correlates to power, but not as closely as anyone thinks
-both of these are true because BSFC (fuel mass required to make X horsepower for X hours) goes up as engine speed increases
Here's a cool chart to show why this is true:
3OugEDm.png
[/thread]
#54
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I am very curious to see pulse width at peak torque and there after.
Also Sav, forgive my stupidity but I've never seen a graph like that. Can you explain what I'm looking at here? Are the camel back lines the torque curves at different load percentages? And what is the pink line? Also not sure why looks like horspower lines are going down while rpms are going up.
Or just point me at some reading materials so I can read up on this.
Also Sav, forgive my stupidity but I've never seen a graph like that. Can you explain what I'm looking at here? Are the camel back lines the torque curves at different load percentages? And what is the pink line? Also not sure why looks like horspower lines are going down while rpms are going up.
Or just point me at some reading materials so I can read up on this.
#56
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Is it safe to say that peak torque is at 4600ish? Looks like pw is still going up until MAF begins to fall. So if 100% dc is hit at peak torque that would be bad news. AFR would have to fall at that point.
#59
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Lots of little things contribute to the consistent rise in PW/IDC that everyone sees in reality. Things like the lack of mixture homogeneity that comes as the injectors are forced to open while the intake valve is open (ideally the entire fuel pulse would be delivered to a closed valve). Increasing BSFC is a big contributor, though - if BSFC goes up by 10%, fuel requirements go up by the exact same amount for the same power/torque being produced.
#60
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Also Sav, forgive my stupidity but I've never seen a graph like that. Can you explain what I'm looking at here? Are the camel back lines the torque curves at different load percentages? And what is the pink line? Also not sure why looks like horspower lines are going down while rpms are going up.
Or just point me at some reading materials so I can read up on this.
Or just point me at some reading materials so I can read up on this.
Horsepower lines are going down because torque goes down as you move down the Y axis. If you multiply RPM and torque anywhere on that chart, you get a horsepower number, and those are shown graphically on the chart by curving lines.
I'm not 100% certain on the pink line, but I believe it is a peak efficiency line from idle to redline.