low impedance vs high impedance injectors?
03-30-2004, 02:27 AM
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low impedance vs high impedance injectors?
What exactly is the difference between low impedance and high impedance fuel injectors?
I'm trying to decide if I want to go with low impedance 550cc injectors or high impedance 600cc injectors?
Any advantages/disadvantages between the two?
Thanks,
Dave
I'm trying to decide if I want to go with low impedance 550cc injectors or high impedance 600cc injectors?
Any advantages/disadvantages between the two?
Thanks,
Dave
03-30-2004, 03:40 AM
#2
Low impedance injectors result in a much higher current which allows them to open really quickly. Problem is that the high current can overheat them. To avoid burning them out the ECU's are designed so they allow an initial high current to open them, then back the current off by controlling the switching transistor. They are often called peak and hold style, as a peak current opens them followed by a lower holding current.
High impedance injectors do not need this current limiting circuitry as their higher impedance limits the current so they dont burn out. They generally do no open as quickly as the low impedance injectors when comparing injectors of the same size, design and actuator mass.
Generally you can put high impedance injectors in place of a low impedance one. Putting a low impedance injector on an ECU designed for high impedance onces will result in excessive current which can damage the ECU or injectors. A bandaid fix is to use ballast resistors. The only problem is you never get the advantage of high initial current to snap them open.
Which is the best. Obviously the low impedance once are preferrable, but only an advantage if your ECU can support peak and hold switching. Otherwise, use whatever injectors you can find to match your required flow rate and physical size requirements and use a ballast if needed.
Speedracer.
High impedance injectors do not need this current limiting circuitry as their higher impedance limits the current so they dont burn out. They generally do no open as quickly as the low impedance injectors when comparing injectors of the same size, design and actuator mass.
Generally you can put high impedance injectors in place of a low impedance one. Putting a low impedance injector on an ECU designed for high impedance onces will result in excessive current which can damage the ECU or injectors. A bandaid fix is to use ballast resistors. The only problem is you never get the advantage of high initial current to snap them open.
Which is the best. Obviously the low impedance once are preferrable, but only an advantage if your ECU can support peak and hold switching. Otherwise, use whatever injectors you can find to match your required flow rate and physical size requirements and use a ballast if needed.
Speedracer.
03-30-2004, 05:17 AM
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wow, thanks! Makes sense.
It's something I've always seen but never really paid attention to. Now that I'm looking for some, it came into play.
Thanks for the help!
It's something I've always seen but never really paid attention to. Now that I'm looking for some, it came into play.
Thanks for the help!
03-30-2004, 07:48 AM
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Not sure about appearance, but you can always measure the resistance of the coil. LI types are generally in the 2-4 ohm range, HI are generally in the 12-16 ohm range.
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03-31-2004, 12:07 AM
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Originally posted by chris_barry
Low impedance injectors result in a much higher current which allows them to open really quickly. Problem is that the high current can overheat them. To avoid burning them out the ECU's are designed so they allow an initial high current to open them, then back the current off by controlling the switching transistor. They are often called peak and hold style, as a peak current opens them followed by a lower holding current.
High impedance injectors do not need this current limiting circuitry as their higher impedance limits the current so they dont burn out. They generally do no open as quickly as the low impedance injectors when comparing injectors of the same size, design and actuator mass.
Generally you can put high impedance injectors in place of a low impedance one. Putting a low impedance injector on an ECU designed for high impedance onces will result in excessive current which can damage the ECU or injectors. A bandaid fix is to use ballast resistors. The only problem is you never get the advantage of high initial current to snap them open.
Which is the best. Obviously the low impedance once are preferrable, but only an advantage if your ECU can support peak and hold switching. Otherwise, use whatever injectors you can find to match your required flow rate and physical size requirements and use a ballast if needed.
Speedracer.
Low impedance injectors result in a much higher current which allows them to open really quickly. Problem is that the high current can overheat them. To avoid burning them out the ECU's are designed so they allow an initial high current to open them, then back the current off by controlling the switching transistor. They are often called peak and hold style, as a peak current opens them followed by a lower holding current.
High impedance injectors do not need this current limiting circuitry as their higher impedance limits the current so they dont burn out. They generally do no open as quickly as the low impedance injectors when comparing injectors of the same size, design and actuator mass.
Generally you can put high impedance injectors in place of a low impedance one. Putting a low impedance injector on an ECU designed for high impedance onces will result in excessive current which can damage the ECU or injectors. A bandaid fix is to use ballast resistors. The only problem is you never get the advantage of high initial current to snap them open.
Which is the best. Obviously the low impedance once are preferrable, but only an advantage if your ECU can support peak and hold switching. Otherwise, use whatever injectors you can find to match your required flow rate and physical size requirements and use a ballast if needed.
Speedracer.
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