Suds7

What are the problems with mixing low and high impedence injectors and haltech, do I need resistors?

RETed

It depends what you are doing.&nbsp You can run one high-impedence or one low-impedence fuel injector on each "channel".&nbsp You can even run a couple high-impedence fuel injector on one injector channel, as long as you don't draw too much current (it's all in the manual).



-Ted

jetenginedoctor

Here’s the gouge on mixing injectors of various impedance (on a Haltech equipped vehicle).

First of all, erase that notion about resistors out of your head. What’s important that you understand is that it’s a matter of injector impedance, not injector resistance. There’s a big difference between the resistance of an injector and the impedance of an injector. What you read with your multmeter is NOT impedance, that’s resistance. Granted, it’s a relatively foolproof way of identifying an injector as being a low or high impedance injector, though not a measure of impedance.

Because it’s not the resistance of the injector that we’re concerned with, the addition of resistors in the circuit will not do anything to help anyone’s situation. Added to a circuit in series will yield a lazy injector because of the reduction in current/voltage available to work the injector. Adding it in parallel will likewise cause a lazy injector, as well as possibly overheating the driver output by adding total circuit current.

Saturation (high impedance) injectors are typically found on most OEM EFI applications as they do not require the additional current clamping circuitry in the ECU that peak-and-hold (low impedance) injectors do. It’s a matter of cost, and auto-makers are all slaves to the bean counters. So why are many high-flow/high performance injectors so costly? What’s up with this whole peak-and-hold injector stuff? It comes down to injector latency. In other words, the low-impedance injector has lower inductive reactance, thus building a field and beginning an injection event more quickly than a high impedance injector. In applications where injection pulsewidth control is a high priority, a low-impedance injector will be better suited than a high impedance injector of the same flow rate.

Now, back to the original question. Yes, you can use both high and low impedance injectors with the E6K. What Ted should have gone on to explain, is that you cannot mix and match injectors of varying impedance on the same driver output channel. Whether you use high/low impedance drivers as primary/secondary injectors on your car makes no difference. Each injector should have it’s own channel in this case, and you’ll need to go into the software and enable the extra injector driver for each channel operating a low impedance injector. Do not put one high impedance injector on one rotor’s primary with a low impedance injector on the other rotor’s primary, even if they have matching flow rates. Same goes with the secondary, of course. It all goes back to the matter of injector latency, and the fact that you’ll never be able to balance those injectors to each other, thus you’ll never be able to achieve a proper state of tune.

I hope this makes sense. If any point needs further elaboration, please don’t hesitate to ask.

BK

BMEP Fuel & Tuning

rxrotary2_7

nice explination.