Injector Duty cycle calculations

[Romans, Mark]

I'm probably wrong but with batch isn't 22ms 100% duty cycle at 6k rpm's?
11ms is common on my car, (165 ecm) 12 ms is too rich with stock 350
injectors running at 50 psi.
Mark
----- Original Message -----
From: <timsiford at hushmail.com>
To: <gmecm at diy-efi.org>
Sent: Sunday, July 23, 2000 6:59 AM
Subject: Re: Injector Duty cycle calculations


> >Remember as you crank the pressure up, you reduce the volume that the
> >pump can produce.
>
> Yes - this is why I am thinking of switching to 30lb injectors.  I don't
> want to run 50+ psi at the rails.  I'm shooting for mid 40's.
>
> >I'm dumb, I just remember 10msec at 6K is 100%, so atta glance your
> >about there.
>
> Yes - this is exactly what I am thinking too.  Let me ask you a quick
question:
>  When the 730ECM reports injector on-time (pulse width), is this the
amount
> of time the injector is on for ONE off-on-off session or the amount of
time
> spend in a double-batch fire (off-on-off-on-off) session?  Its just hard
> to believe that Diacom is reporting 8.3-8.5ms at 6000+ RPMs.  That would
> mean that my injectors are actually on for 16.5 to 17.0ms per 4 strokes.
>  That's A LOT of fuel.  Does that sound correct?  Furthermore, when you
> consider the fact that my 24lb injectors are operating like 28lb injectors
> (due to the greater Fuel pressure) it makes 17.0ms of on-time seem like
> a A LOT for a naturally aspirated 350 for one 4-stroke rotation.  Any
thoughts
> on this?  What does your EFI experience say?
>
> >If the 10 is correct, then he's not in a SEFI mode.
> >10 at 6.5K batch means he's static (injector always on).
>
> Or Diacom is reporting wrongly for either his car or for my car.  We are
> running the same injectors, the same type of intake manifold, and the same
> heads.  His car is faster by a bunch (about 75 more hp - track proven).
>  I would think that he would need to have more fuel and therefore a
greater
> pulse width.  This is just very wierd.  I just want to make sure that if
> I get the 30lb injectors that it is the right decision.
>
> >Really sounds like he's batch
>
> When did GM switch to SEFI?  I made a slight mistake.  The car is a 1996
> Pontiac Formula with the stock ECM.
>
> >Might give em a call, and ask if there are issues about this.
>
> Will do.  Thanks Bruce.
>
> >Get some used GN ones, I just bought a set of 6 for $15.  For the price
> >of checking them, I can't lose.
>
> I'll probably go with a set of SVOs.  I can't leave anything to chance
given
> my goals.
>
> Tim
>
>
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