Megasquirt stage injection
#1
Senior Member
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stage injection
alright guys lets talk about stage injection. what should be the stage scaling factor if you have difference size injector,delay times.are there any calculation to follow in this process. im going to tune a car that have 850 primary and 1600 secondary what the scaling factor should be and delay time for this set up.also where do you found a better transaction on boost or in vac areas what technic do you found better.thanks
#2
Engine, Not Motor
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Copied and pasted from my Megasquirt tutorial:
The scaling factor you enter here will be dependant on the size difference between the primary and secondary injectors. "255" is the number to be used when both injectors are the same size as is OEM in all stock 2nd gens. If you have a larger secondary injector, you must calculate a new scaling factor. To do this, use the following equation:
Scale factor = Primary Injector Size/(Primary Injector Size + Secondary Size)* 512
So if we have 550CC primaries and 1680CC secondaries, it would look like this:
Scale Factor = 550/(550 + 1680)* 512
Scale Factor = (550/2230) * 512
Scale Factor = 0.246 * 512
Scale Factor = 126 (actually 125.9 but I rounded)
You must perform this calculation otherwise the car will be very hard to tune as the secondaries come online and the map will end up with a massive difference in values around the stage point.
I always set my staging to 3500 RPM and 90KpA, which is roughly similar to the stock 3800RPM and 2". Your staging delay is over how many engine cycles the stage takes place. A larger value will give a smoother stage. 60 is a nice point to start at.
The scaling factor you enter here will be dependant on the size difference between the primary and secondary injectors. "255" is the number to be used when both injectors are the same size as is OEM in all stock 2nd gens. If you have a larger secondary injector, you must calculate a new scaling factor. To do this, use the following equation:
Scale factor = Primary Injector Size/(Primary Injector Size + Secondary Size)* 512
So if we have 550CC primaries and 1680CC secondaries, it would look like this:
Scale Factor = 550/(550 + 1680)* 512
Scale Factor = (550/2230) * 512
Scale Factor = 0.246 * 512
Scale Factor = 126 (actually 125.9 but I rounded)
You must perform this calculation otherwise the car will be very hard to tune as the secondaries come online and the map will end up with a massive difference in values around the stage point.
I always set my staging to 3500 RPM and 90KpA, which is roughly similar to the stock 3800RPM and 2". Your staging delay is over how many engine cycles the stage takes place. A larger value will give a smoother stage. 60 is a nice point to start at.
#3
Senior Member
Thread Starter
ok i think i got it. but the car its running real good in the vac areas if i changes the scale factor to a different one would that affect the tune that i already have done in the vac areas.thanks
#5
Senior Member
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ok good since im not have touch the boost part and im going to stages the secondaries at 6 psi so my tune and time tunning the vac area its not waste.
#6
Engine, Not Motor
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Uh, don't do that. Stage your secondaries where they should be in the first place, at around 3500 RPM and 90 KpA. If you stage at 6 PSI, you will find yourself out of fuel well before then and you'll end up having to retune half the map.
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#8
MegaSquirt Mod
Actually, the way you're set up now (and the way I'm set up) allows for you to set staging between 0% staged and 100% staged or anywhere in between on a 6x6 table. It's not duty based at all.
It has also really smoothed out things for me, and makes it so I can freerev as high as I want with no sputtering, I can blip to downshift without staging coming on when I don't want it to, and I can't feel it stage at all... it's completely seamless. Looking at the AFR, it doesn't change at all in response to staging.
Ken
It has also really smoothed out things for me, and makes it so I can freerev as high as I want with no sputtering, I can blip to downshift without staging coming on when I don't want it to, and I can't feel it stage at all... it's completely seamless. Looking at the AFR, it doesn't change at all in response to staging.
Ken
#9
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Thread Starter
i have done it that way with others ecu and no problem at all but im going to try that 90 or 100 kpa and lets see what happen remember the primaries are 850 and thanks
#10
Engine, Not Motor
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That's a bit of a scary way of doing things, but if it works for you then I guess it works. Personally I'd just set it up properly from the beginning as I don't see the advantage of not tuning it from the start.
#11
Senior Member
Thread Starter
i took the car for a spin and when the car boost 4 psi the aem read a lean condition so im going to try to stage at 90kpa and let you know what happen.thanks
#12
1308ccs of awesome
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Actually, the way you're set up now (and the way I'm set up) allows for you to set staging between 0% staged and 100% staged or anywhere in between on a 6x6 table. It's not duty based at all.
It has also really smoothed out things for me, and makes it so I can freerev as high as I want with no sputtering, I can blip to downshift without staging coming on when I don't want it to, and I can't feel it stage at all... it's completely seamless. Looking at the AFR, it doesn't change at all in response to staging.
Ken
It has also really smoothed out things for me, and makes it so I can freerev as high as I want with no sputtering, I can blip to downshift without staging coming on when I don't want it to, and I can't feel it stage at all... it's completely seamless. Looking at the AFR, it doesn't change at all in response to staging.
Ken
I had forgotten I had switched to the new beta staging code.
#25
Senior Member
Thread Starter
the only thing im thinking its previous leans condition due to previous problem with the injector wiring or the boost cut that i hit it a couple times but its set to cut spark and this should not be a problem i think .i dont think i have noise in the ignition because i dont see any noisy rpms in the datalogs rpms seen very clear and the a/f are in the 10s.
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