im using tunerpro and theres a field for injector pulse width in the datalogs, but how can you tell how high they can go? does it vary with injector size?

The highest # I am getting in that column is 10.5mSec.

I am pretty sure I am WAY WAY safe with my engine / injector setup...

So, I didn't really answer your question, but I'd say 10.5 is a safe number.

The way I tell is if I get alot of knock counts at the strip something needs to be done.  Lower the boost which I just can't bring myself to do,  :puke: retard the spark which is just about as hard to do :nono:  or go to bigger injectors.  :thumb: I guess I have had 7 or 8 different sizes in there including some 42#ers. They didn't work. :icon_frown: Thought I was really going to go fast. :icon_cool:

Jud

They say Pintle (ford style) style is safe up to 83% but multitec (GM)can go up to 100 % if they are Peak and hold injectors. The pintle can go higher but for a short burst. They'll stay partly open instead of fully open and closed. It doesn't depend on injector size.

Tunerpro only shows the injector pulse width in mSec, not %, right?

Quote from: mfewtrail on May 18, 2007, 09:29:22 PM
Tunerpro only shows the injector pulse width in mSec, not %, right?

correct, unless if theres a ALDL datastream that shows % im not aware of

If I'm remembering right I THINK 7 msec is about 85% duty cycle

It depends on the RPM of the motor and I think you could calculate it from there.  From experience with my 4500 RPM Syclone, the injectors are "wide open" after about 17ms.. 

The best way to tell if you're out of injector is by checking a wideband AFR gauge and seeing if it goes lean at max power, even after you add more fuel. That's what happened to me, although I was both out of injector, and out of fuel pump.  Now I have 28# Syclone injectors and a Walbro 255 fuel pump, and it's a ton more fuel than I need right now.  In fact when I finished the fuel pump install, my 12.5 WOT AFR went to off the charts RICH!!  And I'm only at 12.3ms of max BPW .

I suspect if I had a fuel pressure gauge installed, I would have seen that drop off as well with the stock fuel pump unable to supply the capacity needed.