high rev prom tune
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From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
high rev prom tune
The equations for maximum injector size is well known and most people rough in the injector constant for decent BLMs. What happens when it works out for the case of getting the constant for WOT right, but then the idle base pulse width (BPW) is very low? I was thinking turn down the constant and mess up the flow in the tables. What is too low of a pulse width for an injector anyway? Maybe 1 ms or so? High revving engines seem to have this problem.
Thanks,
J
Thanks,
J
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Joined: Feb 2002
Posts: 156
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What happens when it works out for the case of getting the constant for WOT right, but then the idle base pulse width (BPW) is very low?
This actually has nothing to do with the constant. If you change the constant then the computer will adjust for idle. Because the engine requires a certain amount of fuel the actual flow rate determines the pulse length. If you change any one variable while calculating that number the ECM will change the BLM to compensate.
What is too low of a pulse width for an injector anyway? Maybe 1 ms or so?
In a sat inj 1 ms is too low. I start worrying about 1.8-1.9ms but then again I have no real data on when the injectors I am running become unstable at the pressure I am running at. I also have no intentions of testing that boundary.
High revving engines seem to have this problem.
I think that you see this alot in batch fire engines that fire the injectors every rev. I intend to write some code that will compare the PW to a minimum PW. If the PW is smaller than the minimum then the ECM will store that time and inject no fuel. On the next rev it will add the stored time to the new time. This will allow for the correct amount of fuel for the cycle but allow for larger injectors without injector instability.
HTH
John
This actually has nothing to do with the constant. If you change the constant then the computer will adjust for idle. Because the engine requires a certain amount of fuel the actual flow rate determines the pulse length. If you change any one variable while calculating that number the ECM will change the BLM to compensate.
What is too low of a pulse width for an injector anyway? Maybe 1 ms or so?
In a sat inj 1 ms is too low. I start worrying about 1.8-1.9ms but then again I have no real data on when the injectors I am running become unstable at the pressure I am running at. I also have no intentions of testing that boundary.
High revving engines seem to have this problem.
I think that you see this alot in batch fire engines that fire the injectors every rev. I intend to write some code that will compare the PW to a minimum PW. If the PW is smaller than the minimum then the ECM will store that time and inject no fuel. On the next rev it will add the stored time to the new time. This will allow for the correct amount of fuel for the cycle but allow for larger injectors without injector instability.
HTH
John
Thread Starter
Supreme Member
iTrader: (1)
Joined: Jan 2002
Posts: 4,432
Likes: 1
From: garage
Engine: 3xx ci tubo
Transmission: 4L60E & 4L80E
What happens when it works out for the case of getting the constant for WOT right, but then
the idle base pulse width (BPW) is very low?
This actually has nothing to do with the constant. If you change the constant then the computer
will adjust for idle. Because the engine requires a certain amount of fuel the actual flow rate
determines the pulse length. If you change any one variable while calculating that number the ECM
will change the BLM to compensate.
the idle base pulse width (BPW) is very low?
This actually has nothing to do with the constant. If you change the constant then the computer
will adjust for idle. Because the engine requires a certain amount of fuel the actual flow rate
determines the pulse length. If you change any one variable while calculating that number the ECM
will change the BLM to compensate.
n a sat inj 1 ms is too low. I start worrying about 1.8-1.9ms but then again I have no real data on
when the injectors I am running become unstable at the pressure I am running at. I also have no
intentions of testing that boundary.
when the injectors I am running become unstable at the pressure I am running at. I also have no
intentions of testing that boundary.
High revving engines seem to have this problem.
I think that you see this alot in batch fire engines that fire the injectors every rev. I intend to write
some code that will compare the PW to a minimum PW. If the PW is smaller than the minimum then
the ECM will store that time and inject no fuel. On the next rev it will add the stored time to the
new time. This will allow for the correct amount of fuel for the cycle but allow for larger injectors
without injector instability.
I think that you see this alot in batch fire engines that fire the injectors every rev. I intend to write
some code that will compare the PW to a minimum PW. If the PW is smaller than the minimum then
the ECM will store that time and inject no fuel. On the next rev it will add the stored time to the
new time. This will allow for the correct amount of fuel for the cycle but allow for larger injectors
without injector instability.
I wonder how this is going to come out. This text looks pretty messed up in this edit box!
Thanks,
J
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