Injector Questions
Injector Questions What is the difference between high and low impedance injectors? Is the flow rating the maximum output or is that the constant output? i.e. Would you be able to use 36 or 40 Lb. injectors on a stock motor, or would this make it run really rich?
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I'm no pro, but let me give you a layman's perspective.
Impedance (Z) is opposition to current flow in an alternating current circuit, made up of two components, ohmic resistance and reactance. You can't just say resistance, because Reactance is really opposition to the flow of alternating current caused by the inductance and capacitance in a circuit rather than just by resistance. I remember this from my Navy Electronics Tech days.
Anyway, circuits within electronic systems are matched in impedance... this is true even in the sound reinforcement and recording industry. Higher impedance circuits have more resistance to flow and drop more power across runs of wiring. They also are more prone to picking up RF (radio frequency) if not shield very well. Almost everyone uses lo-Z mics and cables now, instead of the hi-Z kind. But, hi-Z is cheaper.
So, lo-z injectors behave better at higher rates of fuel flow than hi-Z injectors. So, we wanna put lo-Z injectors on. But guess what? We are hooking those injectors up to a circuit designed to operate with hi-Z injectors. The signals aren't compatible. SO, we have to have a converter modify the Hi-Z signals from the PCM flowing to the injectors. If there is communication back to the PCM from the injectors (I don't know that there is) these signals would have to be converted from lo-Z to hi-Z for the PCM.
Did I just help, more make it confusing.
Impedance (Z) is opposition to current flow in an alternating current circuit, made up of two components, ohmic resistance and reactance. You can't just say resistance, because Reactance is really opposition to the flow of alternating current caused by the inductance and capacitance in a circuit rather than just by resistance. I remember this from my Navy Electronics Tech days.
Anyway, circuits within electronic systems are matched in impedance... this is true even in the sound reinforcement and recording industry. Higher impedance circuits have more resistance to flow and drop more power across runs of wiring. They also are more prone to picking up RF (radio frequency) if not shield very well. Almost everyone uses lo-Z mics and cables now, instead of the hi-Z kind. But, hi-Z is cheaper.
So, lo-z injectors behave better at higher rates of fuel flow than hi-Z injectors. So, we wanna put lo-Z injectors on. But guess what? We are hooking those injectors up to a circuit designed to operate with hi-Z injectors. The signals aren't compatible. SO, we have to have a converter modify the Hi-Z signals from the PCM flowing to the injectors. If there is communication back to the PCM from the injectors (I don't know that there is) these signals would have to be converted from lo-Z to hi-Z for the PCM.
Did I just help, more make it confusing.
Litlle bit of help little bit added confusion. But, that's OK. So, race injectors would more than likely be lower resistance. I was looking at injectors the other day and noticed that they don't go to low impedance until about 55 Lbs/Hr. flow rating. I may need this kind of flow in the future but for right now the stock injectors should be fine. What is the flow rating for the stock 99 injectors?
Originally Posted by Local Sponsor Webpage
Injector Impedance Converter
The Impedance Converter uses your engine computer injector signals to trigger separate "peak and hold" logic circuits for each injector. The "peak" part of the peak and hold circuit is capable of providing the large electric current needed to snap big injectors open quickly, something your engine control computer cannot do. Once the injector is open, the "hold" part of the circuit turns down the electric current to prevent the injector from getting too hot. Your engine control computer will never know that it's running the Impedance Converter instead of the injectors. Use of the Impedance Converter will not cause your engine control computer to "throw a code", or turn on the check engine light, or do anything else that would be annoying. The Impedance Converter comes with everything you need to hook it up. The connectors are the same Weather-Packs chosen by automakers for their moisture, dust, and vibration resistance.
The Impedance Converter uses your engine computer injector signals to trigger separate "peak and hold" logic circuits for each injector. The "peak" part of the peak and hold circuit is capable of providing the large electric current needed to snap big injectors open quickly, something your engine control computer cannot do. Once the injector is open, the "hold" part of the circuit turns down the electric current to prevent the injector from getting too hot. Your engine control computer will never know that it's running the Impedance Converter instead of the injectors. Use of the Impedance Converter will not cause your engine control computer to "throw a code", or turn on the check engine light, or do anything else that would be annoying. The Impedance Converter comes with everything you need to hook it up. The connectors are the same Weather-Packs chosen by automakers for their moisture, dust, and vibration resistance.
Originally Posted by Cali99SS
What is the difference between high and low impedance injectors?
Is the flow rating the maximum output or is that the constant output? i.e. Would you be able to use 36 or 40 Lb. injectors on a stock motor, or would this make it run really rich?
The stock injectors are fine for stock motors and up to at least 400 RWHP, and perhaps more like 450 RWHP. You really need to monitor injector pulse width with an OBDII logging tool to decide. Unless you are over 90 to 95%, there is no point is putting in larger (higher flow) injectors.
