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Re: Ford injectors (& Question) MORE
> I analized the pulse widths that I am getting (383 CI TPI w/ stock 22#
> injectors, 360 HP est) verses the max PW for a range of RPM's (3600 -
5500
> : My "drag zone") and although I am seeing 13 ms pulses, they occur in an
> rpm range that allow a maximum of 16 msec thus my duty cycle times are
FINE!
Yep.
> RPM/ MAX Allowable PW/ Measured PW /Measured Duty Cycle
>
> 3600 16.7 12.9 77.4
> 3750 16.0 12.3 76.875
> 3900 15.4 12.4 80.6
> 4050 14.8 12 81
> 4200 14.3 11.6 81.2
> 4350 13.8 11.2 81.2
> 4500 13.3 11 82.5
> 4650 12.9 10.8 83.7
> 4800 12.5 10.5 84
> 4950 12.1 10 82.5
> 5100 11.8 9.3 79.05
> 5250 11.4 9.2 80.5
> Conclusion: My stock 22# TPI injectors are correctly sized for my stroker
/
> large tube / header / 13.1 E.T. setup, even though I have PW's that are
over
> 10 ms.
> Right or Wrong???
10 at 6K rpm, means your in trouble as well as 20 msec at 3K rpm
Your DC (assuming your math is right) is fine.
What heads, max timing ya running?
Bruce
> TIA (again)
>
>
>
> ----- Original Message -----
> From: Dave Zug <dzug@delanet.com>
> To: <gmecm@diy-efi.org>
> Sent: Saturday, August 19, 2000 2:19 AM
> Subject: Re: Ford injectors (& Question)
>
>
> > Thanks Roger.. I see my mistake. Much thanks.
> >
> > ----- Original Message -----
> > From: Roger Heflin <rah@horizon.hit.net>
> > To: <gmecm@diy-efi.org>
> > Sent: Friday, August 18, 2000 3:50 PM
> > Subject: Re: Ford injectors (& Question)
> >
> >
> > >
> > >
> > > On Fri, 18 Aug 2000, Dave Zug. wrote:
> > >
> > > >
> > > > So if I have this right, Let me write this in other terms...
> > > >
> > > > Lets say for example a car cruising is doing 5 ms pulses at a
constant
> > 6000
> > > > rpm (for math's sake).
> > > >
> > > > Its pulsing like this:
> > > >
> > > > each bit is 0.5 ms: (2 crank revs = 1 cam rev =20 bits). 20 ms time
is
> > > > represented (4 engine "strokes").
> > > >
> > > > 1111100000 1111100000 1111100000 1111100000 Left
> > > > 0000011111 0000011111 0000011111 0000011111 Right
> > > > <----------10 ms--------> <---------10 ms--------->
> > > >
> > > > Alternating left and right for HALF the PW time each 10 ms to
complete
> > the
> > > > full PW time within one CAM rev.
> > > >
> > > > Then we go to WOT and for math's sake lets say we gain no RPM's or
> > fueling
> > > > requirements.
> > > >
> > > > Its pulsing like this:
> > > >
> > > > each bit is 0.5 ms:
> > > >
> > > > 1111100000 1111100000 1111100000 1111100000 Left
> > > > 1111100000 1111100000 1111100000 1111100000 Right
> > > > <----------10 ms--------> <---------10 ms--------->
> > > >
> > > > Now to the (almost) REAL world.. Heres what WOT looks like (constant
9
> > ms
> > > > requirement) :
> > > >
> > > > each bit is 0.5 ms:
> > > >
> > > > 1111111110 1111111110 1111111110 1111111110 Left
> > > > 1111111110 1111111110 1111111110 1111111110 Right
> > > > <----------10 ms--------> <---------10 ms--------->
> > > >
> > > > The above example has the injectors on IN UNISON for a total of (0.5
> ms
> > *
> > > > 18) or 9 ms over each 10 ms (1/2 valvetrain cycle) period. the
listed
> PW
> > > > then repeats itself for the next 10 ms with no recalculation taking
> > place
> > > > (??) to complete the valvetrain cycle.
> > > >
> > > >
> > > > Do I have it right?
> > >
> > > Close, I believe they actually pulse the given pulsewidth at once, so
> > > when the computer says 9ms it actually opens it for 9ms, and then
> > > closes for 1ms, not (4.5ms, close .5, 4.5, close .5) On the
> > > sequential cars it would list 9ms as 18 ms, and keep it open for I
> > > believe the entire time or almost the entire cam rotation. I don't
> > > know if they alternate banks, I would need to look at the code to
> > > figure out that and how exactly it compares to the actual cylinder
> > > timing. My guess is that it may not really even match up consistantly
> > > with the cylinder timing, just close enough, I suspect also since the
> > > injectors have difficulties with being closed for short periods of
> > > time that that may be the reason to not even try to time single
> > > cylinder events, since this would required bigger injectors to avoid
> > > getting the close time too low.
> > >
> > > Roger
> > >
> >
>
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> >
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