What are the biggest injectors you can run with the ls1 pcm, piggy back, or stand alone? Who makes them. I can't remember if it is high impedence or low impedence that is a problem. Thanks.

 

You can only run High impedene injectors with the stock PCM..... RC Engineering makes 75# inj. but there spendy...... $750......
Kyle

 

i bought my 75#ers for 500, i got a good deal on it. i wonder how much power they are good to?

 

High Impedence?

Ummm where....I would buy those in a heartbeat.

 

there was another guy on ls1tech i think that was selling it for 500.

this is the link i bought mine from. do a search. you might find something on ls2.com also

https://ls1tech.com/forums/showthrea...rc+engineering

 

http://www.ls2.com/forums/showthread...ring+injectors

theres the other link for the 500 buck inj's.

i dont know if he sold it yet, just that its still posted.

good luck and let us know if you get em.

 

Thanks, going to contact them now!

 

You can run anything you want.

Go to www.acceleronics.com. They have a box to allow low impedance injectors to be run with the GM PCM. And there are hundreds in use.

Perry

 

That's right, for $799 you can get a VersaFueler low impedance injector driver AND a set of flow matched injectors in your choice of sizes from 65 lb/hr to 160 lb/hr. The most popular choices are the Siemens 72s and 83s, and the Delphi 75s and 95s.

I hope you guys won't consider this spam! Here's my experience with big, high impedance injectors:
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I’ve tested a lot of big, high impedance injectors on the Acceleronics injector flow bench. They have two major problems, both caused by the simple fact that they are high-impedance. First, they open very slowly compared to stock injectors, and compared to low impedance injectors. Second, the variation in opening time from injector to injector is much greater.

You can minimize the poor driveability caused by slow opening time by increasing the injector offset value in your ECU. This offset is the amount of time added by the ECU to compensate for injector opening time. Stock values are typically in the 1/4 to 1/3 millisecond range. I had to bump that number up to 1 millisecond when I ran 50 lb/hr high impedance injectors. They were 3 to 4 times slower than the stockers! I’m currently running 95 lb/hr Delphis on the street with the stock offsets.

The bigger problem with big, high impedance injectors is the variation in the minimum opening time from injector to injector. Here’s an example based on tests I’ve run on the flow bench.

Suppose injector A needs at least 1.0 millisecond to open. By that I mean, if you give it a 0.9 millisecond pulsewidth, it will not open at all. It takes at least 1.0 millisecond to get any fuel out of it. (I see this all the time on the flow bench). Injector B needs 1.5 milliseconds to open. I have seen 0.5 millisecond variations between injectors with the same flow rating on the bench.

Now let’s say your engine idles with 1.5 millisecond pulsewidths. To compensate for the opening time of injector A, you tune the ECU to command a total pulsewidth of 1.0 + 1.5 = 2.5 millisecond. But injector B is only open for 2.5 – 1.5 = 1.0 millisecond. Cylinder B’s fueling is off by 50%! Would you buy “flow matched” injectors if their measured flow rates were different by 50%? Cylinder B is going to be very lean, and probably misfiring.

You can bump the injector offset to 1.5 to compensate for injector B. Now the total idle pulsewidth will be 1.5 + 1.5 = 3.0 millisecond. Cylinder B gets the 1.5 milliseconds it needs, but cylinder A is getting 3.0 – 1.0 = 2.0 milliseconds. It’s pig rich, getting 33% more fuel than it needs.

This is the main reason why guys have a hard time getting big, high impedance injectors to idle well, and why the throttle response is not as crisp as it would be with properly sized low impedance injectors. I have had many, many customers confirm that they could never get their car to run well with the big, high impedance injectors they were running when they called me.

Why are low impedance injectors so much faster? Because they use about 4 times the opening power of high impedance injectors. Low impedance injectors pull about 4 amps of electric current to open, compared with about 1 amp for high impedance injectors. 4 times the current means 4 times the power (since the voltage is the same for both injectors). So ask yourself, is a 1000hp car faster than a 250hp car of the same weight?