white924s

haha...whoops, thanks for the heads up....

Darwantae951

Cone_eater

So what is a good 30-36lb injector?

Darwantae951

I realize that this is not pertinent to this thread, but 951 injectors are 4.5 ohms.

You may want to specify

"what is a good low impedance 30-36lb injector"

-Darwin

Cone_eater

what does "low impedance" mean? And can a high impedance be used? What happens?

Darwantae951

"Low" or "high" impedance is in reference to the resistance, in ohms, of the injector.

Cone_eater

But why does this make such a difference? What happens if you use a high impedance?

V2Rocket

the ford supercoupe/porsche 951 injector (same part) is a low-impedance, 36 lb/hr injector. it will plug into your manifold and into your harness.

Darwantae951

This is how I understand it (if I'm wrong, then someone please correct me):

If you use a low impedance injector on a 951 (for example) then the injector drivers will send too much power to them and they won't use it all. That stored energy will stay in the injector driver circuit in the DME and could potentially damage it. This is usually only an issue if you are WOT most of the time (like a track car) and doesn't make much heat if you're just cruising.

**DISCLAIMER: The above is MY understanding. If I'm wrong, lemme know!**

white924s

Darwin, I think you're basically correct. My understanding is somewhat simpler - the injector circuit was designed by Porsche for injectors of a certain impedance. Putting injectors with the wrong impedance in there will throw voltages all over the circuit out of whack and likely break something. You can use ballast resistors to get the total impedance to the right number, but you really want to do that if you're going to change injectors

Darwantae951

I added ballast resistors for my low impedance Siemens 55lb injectors. It was really easy to do.

blown 944

They are not the same part but seem to flow very close to each other. The turbo are green top (4.5 ohm) Bosch and the supercoupe are brown top (2.8ohm) Bosch.

The difference is that a low impedance is generally around 2.2-2.8 ohm and is peak hold design

the high are around 16 ohm and are saturated design.

they are not interchangable. However you can use low impedance in the 951 (4.5 oddball) for street use from what I hear they overheat the drivers in a race app and need resistors. If you try to run a high on a low driver setup it will run very lean.

edit to add : the n/a is a low impedance setup

Cone_eater

How do you run a res?

blown 944

they are inline spliced into the injector wires

unless you are talking about a 951 there is no need

Darwantae951

Yes, this is correct. I didn't mean to cause any confusion. Sorry!