Tuning 30# SVO Injectors - Did search
05-30-2008, 10:19 AM
#1
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Tuning 30# SVO Injectors - Did search
I know when changing to 30# SVO Injectors to change the injector constant to 31.68. Is there anything else that needs to be changed, such as offsets, or is it just as simple as changing the injector constant?
06-03-2008, 07:34 AM
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Location: Upstate New York,USA
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Keep in mind this is what I recall from years on the lists/boards. If I'm offbase here, someone chime in....
In the LT1 editor, there are injector offsets in the Fuel tab where you can designate small voltage 'offsets' to do 'fine tuning' per cylinder. This was provided by automakers to compensate for small individual efficiencies/deficiencies between cylinder to cylinder variances. The factory settings are defined for the stock poundage fuel injectors. When you switch to a larger pintle of a larger injector, it takes a bit more voltage (at least in some cases) to overcome the inertia of the heavier (however microscopically so) pintle. Most manufacturers provide a data sheet of injector offsets that are notated per cylinder (yes, it's not, for example, .031 for all 8. It can be .031, .037, .030, etc) The reason the variance occurs is somewhat obvious if you consider the position of the Throttle body relative to the proximity of the various ports it has to serve and the firing order of a given motor. All of these influence the ability to get a equal 'gulp of air' for the induction event. The back cylinders (farthest away from the throttle body) are last in line for the inbound air, they may need less fuel to keep from running rich. But then you have the firing order too which can impede a cylinder from getting a clear clean, symmetrical volume of air. For example, using the LT1/SBC firing order of 1-8-4-3-6-5-7-2. we see adjoining bank cylinder 7 will be potentially at a disadvantage what with cylinder 5 just having opened right beside it. This could render cylinder 7 a bit less able to get an otherwise equal volume of air compared to cylinder 5 that had first chance at the plenum volume. The offsets are therefore introduced to try to keep Cylinder to Cylinder Air Fuel Ratios consistent.
David K. Wilson
In the LT1 editor, there are injector offsets in the Fuel tab where you can designate small voltage 'offsets' to do 'fine tuning' per cylinder. This was provided by automakers to compensate for small individual efficiencies/deficiencies between cylinder to cylinder variances. The factory settings are defined for the stock poundage fuel injectors. When you switch to a larger pintle of a larger injector, it takes a bit more voltage (at least in some cases) to overcome the inertia of the heavier (however microscopically so) pintle. Most manufacturers provide a data sheet of injector offsets that are notated per cylinder (yes, it's not, for example, .031 for all 8. It can be .031, .037, .030, etc) The reason the variance occurs is somewhat obvious if you consider the position of the Throttle body relative to the proximity of the various ports it has to serve and the firing order of a given motor. All of these influence the ability to get a equal 'gulp of air' for the induction event. The back cylinders (farthest away from the throttle body) are last in line for the inbound air, they may need less fuel to keep from running rich. But then you have the firing order too which can impede a cylinder from getting a clear clean, symmetrical volume of air. For example, using the LT1/SBC firing order of 1-8-4-3-6-5-7-2. we see adjoining bank cylinder 7 will be potentially at a disadvantage what with cylinder 5 just having opened right beside it. This could render cylinder 7 a bit less able to get an otherwise equal volume of air compared to cylinder 5 that had first chance at the plenum volume. The offsets are therefore introduced to try to keep Cylinder to Cylinder Air Fuel Ratios consistent.
David K. Wilson
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