ATAP Questions: Maxing out injectors?

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May 8, 2003 | 08:59 PM

Blown Hawk

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ATAP Questions: Maxing out injectors?

Well the procharger is on, the fuel system is complete. And there's only a few minor things to finish up tomorrow before firing her up. I decided not to install the inline pump and just run off the walbro intank.

My question is about knowing when I need to upgrade my fueling system.

In ATAP, how can I find how hard my injectors are working? I'm assuming that if the injectors are working too hard the only solution is to upgrade to bigger injectors correct?

Also how can I tell if my walbro is keeping up with the needs of my injectors? (Keep in mind I have a boost referenced FPR)

I'm so psyched guys. I just have to wire up the gauges and cover the hole in the trunk and it's all done. I have a feeling this is gonna be one of those memorable Fridays

Mike

May 9, 2003 | 07:49 AM

AzzHauler

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Re: ATAP Questions: Maxing out injectors?

You can log the injector pulse width (BPW) in atap. It tells how long the pcm wants the injector open. The problem comes in when the pcm wants it open longer that the time available, dictated by rpm and intake duration on the cam I believe. In high rpms the window is smaller so that's the most likely place to have trouble. Someone else might have a more complete answer, or you might find something in the pcm forum.

May 9, 2003 | 07:50 AM

AzzHauler

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Re: ATAP Questions: Maxing out injectors?

Oh yeah, can't wait to hear about the new toys!

May 9, 2003 | 10:05 AM

DarkFormula

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Re: ATAP Questions: Maxing out injectors?

Take a look at the injector duty cycle, it's never supposed to be at 100%!

I was running 5lbs through my ATI with stock 28# injectors and an FMU. I was reaching full duty cycle at 4000 RPMs, that's bad

I *think* the duty cycle should never reach more than 80% anywhere in the RPM band. If it increases past this, it's time to get bigger injectors

May 9, 2003 | 01:09 PM

Crunch

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Re: ATAP Questions: Maxing out injectors?

Quote:

Take a look at the injector duty cycle, it's never supposed to be at 100%!

From what I understand, this is correct. Autotap showed I was running at 100% at around 5000RPMs with 38# injectors. So we swapped over to 50# to solve this problem. When I get my rebuild done, i'm hoping this will buy a little more power.

May 9, 2003 | 03:01 PM

Ryan23silverado

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Re: ATAP Questions: Maxing out injectors?

Where do you find this in AutoTap? I pull up the screen to Show All options that I can log on the car (1999 Truck in my case), and I do not see Injector duty cycle or the percentage at which the injectors are working

Help, I know I am on the edge with the injectors I have now, but can't see this in AutoTap.

May 9, 2003 | 11:52 PM

AzzHauler

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Re: ATAP Questions: Maxing out injectors?

I haven't seen duty cycle as a selectable 'sensor'. That's why I was talking about pulse width. Duty cycle is a calculated value, just like g/cyl for timing.