low or high impedance ?

[nissag250]

Hi,
what are the differences between low and high impedance injectors ?
what advantages for the two options ?

[Stag76]

For ordinary use, they both do the same job. High Impedance are easier to use with MegaSquirt...just set them and forget them. Low impedance require some experimentation with the PWM Settings, and this can be a lengthy and testing procedure. Low impedance can also be run via a resistor pack which then allows MegaSquirt to treat them in the same manner as high impedance. If you source low impedance injectors from another engine, try to get the resistor pack with them, and avoid running them by PWM.

[Bernard Fife]

nissag250,

Setting the PWM parameters is easy, it's just takes a minute or two to do this following the instructions in the manual, and it only has to be done once.

Hi-impedance injectors don't require PWM, or the tuning that goes with them.

However, higher flow rate injectors tend to be only available as low impedance. This includes most TBI injectors, and the majority of very high flow port injectors. Lo-impedance injectors tend to open faster (making better use of the time available to inject fuel) and this is especially important when using high flow rate injectors. You can use resistors with with lo-impedance injectors, but the proper resistors aren't cheap ($5-$10 each), and it's yet another set of connections to fail (and the resistors slow the opening time as well).

Either lo or hi impedance injectors work fine if set up properly, and I have run both on my vehicles with MegaSquirt for years. Once I have the PWM set as in the manual, I never look at it again.

Lance.

[kjones6039]

Low-impedance injectors don't require PWM, or the tuning that goes with them.

I never thought the day would come that I would ever get a chance to correct Lance, but.....
This must be a typo, huh?

With all respect,

Ken

[nissag250]

Thank you .
well i have high impedance injectors from ITB's gsxr 750 SRAD 99,for my DATSUN L6 , N/A, and their flow is 220 CC/MN so it's enough for me, i'll keep them

Regards
Didier

[Bernard Fife]

Ken,

Thanks for the correction, I have fixed my post to reflect that.

I make more mistakes before breakfast than most people do all day, and I am always happy to be corrected!

Lance.