Fuel Injector Timing as Compared to Engine Cycle
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From: Rockville, MD
Fuel Injector Timing as Compared to Engine Cycle because insomnia sucks, here goes.
on the HPTuners forum, it has been figured that the LS1 engine computers use a 0.0 to 8.0 reference table to calculate injector timing with a set Boundary point that the normal references off of. the normal is to be done a certain number of reference points after the boundary point.
now, as I understand it, it is a 720* engine cycle reference with 0 being 0* and 8.0 being 720* (each full point is 90*). with stock values of a 6.5 boundary and a normal of 5.55. this equates to a 585* boundary and a 499.5* normal. doing the math 499.5-(720-585) comes to.. an injection finishing point of 364.5*.
of course, this stock stuff is all well and good for a stock cam engine. if change any of it... well.. like most other parameter in the ecu, it needs to be changed.
what i have found with the torquer 2 cam in the ss is that a simple injector timing change does more than one would think: better idle quality, MUCH easier cold start, smoother running, no gassy smell, SOTP torque increase in lower rpm, etc. you might think "yea, but whats the point that gets it put here?"
the questions are: why choose a boundary of 6.5 when a seemingly infinite combination of values will result in the same injector timing? and there is some consensus on putting the timing of the injectors in line with the highest air velocity created during camshafts intake cycle. what would be a reliable way to do that?
on the HPTuners forum, it has been figured that the LS1 engine computers use a 0.0 to 8.0 reference table to calculate injector timing with a set Boundary point that the normal references off of. the normal is to be done a certain number of reference points after the boundary point.
now, as I understand it, it is a 720* engine cycle reference with 0 being 0* and 8.0 being 720* (each full point is 90*). with stock values of a 6.5 boundary and a normal of 5.55. this equates to a 585* boundary and a 499.5* normal. doing the math 499.5-(720-585) comes to.. an injection finishing point of 364.5*.
of course, this stock stuff is all well and good for a stock cam engine. if change any of it... well.. like most other parameter in the ecu, it needs to be changed.
what i have found with the torquer 2 cam in the ss is that a simple injector timing change does more than one would think: better idle quality, MUCH easier cold start, smoother running, no gassy smell, SOTP torque increase in lower rpm, etc. you might think "yea, but whats the point that gets it put here?"
the questions are: why choose a boundary of 6.5 when a seemingly infinite combination of values will result in the same injector timing? and there is some consensus on putting the timing of the injectors in line with the highest air velocity created during camshafts intake cycle. what would be a reliable way to do that?
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From: Norn Iron
The only way to configure injector timing. Is in a controlled environment where you can monitor the changes it makes, to improve whatever you are seeking to improve.
Generally it will clean up emissions and help economy, which both in turn will have positive effects on how the engine performs all over.
That will apply to all load sites, but biggest improvements will be at lower rpm's
Generally it will clean up emissions and help economy, which both in turn will have positive effects on how the engine performs all over.
That will apply to all load sites, but biggest improvements will be at lower rpm's
