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Electrical impedance math

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If it's not really about tuning or wiring. Then it belongs in here.


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Hi - I have a (silly) question regarding the injector drives on a Link g4+ . Most Links can only run high impedance injectors right ? But to take advantage of the myriad of low impedance on TM for sale is it possible to wire 2 drives together and power 2 or 3 low z injectors together ? For example - in group fire with 4 injector drives they fire in sets of 2 - so if you wire drive 1 and 3 together would you have enough current to drive say 3 low z injectors wired in series ? If wired in series resistance goes up right ? So if 3 - 3 ohm injectors were wired in series youd have 9 ohms and with 2 injector drives wired together youd have 10 amps of driver current ? Could this work in batch fire on a 6 cylinder ? Does the math work ?

If you want to run low Z injectors with a saturated driver you will need to use the matching ballast resistor. The reason low impedance injectors must be used with either P&H drivers or ballast resistors is you need to limit the current through their coil. If you dont limit the current, the injector coil will overheat, usually melting the insulation and if you are unlucky send 12V straight into the ECU driver and fry it.

2nd hand injectors arent usually a good way to go unless you are going to at least flow test them all. What flow rate do you need?

Ok - Thanks for explaining that and how the low Z injectors work - It was just a thought and i had no particular flow rate in mind . Cheers .

A couple of decent low cost options that I have used in the past:

VDO/Siemens FI11354S (Dodge Neon SRT). About 480cc @ 3Bar. 3/4 length inj (48mm). Good general purpose spray pattern. You will find them on Rockauto for about USD$35 each. Fedex to NZ about $12.

Bosch 62019 (Ford Mustang GT500). About 610cc @3bar. Full length. Odd dual cone spray pattern, suggest only use in 4 valve engines. About $40 each on Rockauto.