Nother thought

[timsiford at hushmail.com]

Ahhhh ... thats the difference right there.

Assuming an IPW of 10.0ms from 5000 to 6500rpms....
5200rpms = 87% DC
6500rpms = 108%DC
This assumes batch fire and does not account for opening a closing.

Yes - I know that the IPW will drop off a tad bit at higher RPMs.  But, 
keep in mind that with a MiniRam setup it won't fall off much.

Tim

At Sat, 7 Oct 2000 00:04:57 -0700, "Dave Zug" <dzug at delanet.com> wrote:

>
>Dart pro-1 Alum. 45# FP,  have to shift at 5200-5300 or so. power dies 
>above
>that. Stock lower intake is a very effective restrictor mechanism.. 
> man the
>torque though!  I even have 1.6's on the exhaust valves.  the CR is 
>9.8 : 1.
>Very comfortable in daily driving. the only lightweight component is 
>the
>fibreglass hood.  speaker box in the trunk helps with 60' but trap speed 
>is
>only 103. This is on a street chip and 89 octane... the way I take it 
>to the
>track all the time.  Working on implementing a very low HP (#14 jet,
> dry)
>NOS kicker in conjunction with a little ECM fueling to get those last 
>2
>tenths. (12.99 target).  edelbrock lower intake is slated for winter
>project, and DSL.
>
>----- Original Message -----
>From: <timsiford at hushmail.com>
>To: <gmecm at diy-efi.org>
>Sent: Thursday, October 05, 2000 3:00 PM
>Subject: Re: Nother thought
>
>
>>
>> >I think theres enough info here for my concerns to evaporate.
>>
>> You were concerned about lil 'ol me?  j/k  Thanks for lookin' out. 
> I
>CANNOT
>> believe you are getting away with 22lb injectors on a 383 with a ZZ4 
>cam.
>>  What heads are you running?  At what RPM are you shifting?
>>
>> Tim
>>
>> >
>> >----- Original Message -----
>> >From: <timsiford at hushmail.com>
>> >To: <gmecm at diy-efi.org>
>> >Sent: Thursday, October 05, 2000 11:02 AM
>> >Subject: Re: Nother thought
>> >
>> >
>> >> Dave,
>> >>
>> >> Understood.  I'm in class right now but I'll post the PWs that 
>gave
>> >me the
>> >> 100% DC later tonight.  I wrote a convenient VB program that I 
>use
>> >to
>> >calculate
>> >> all sorts of Automotive data.  The DC is based on batch fire cars
>> >where
>> >> 100% DC was equivalent to an injector Pulse Width of 10.0ms at
>6000RPMs.
>> >>  I'll post the full formula later.  NOTE:  I didn't consider opening
>> >and
>> >> closing time.  Thus, the DCs could be even higher.  I went over 
>and
>> >over
>> >> and over swapping out my injectors.  Everyone in MAFB said that 
>I
>> >shouldn't
>> >> need to go higher than 24lb injectors.  Diacom also reported AOK 
>O2
>> >voltages
>> >> at WOT throughout the entire WOT run (0rpms->6500rpms).  I replaced
>> >my
>> >injectors
>> >> SOLELY because of the DCs I was seeing.  Many people told me not 
>to
>> >replace
>> >> my injectors ... that the 22lb injectors would be enough.  Diacom
>> >supported
>> >> that.  But, the DCs did not (and I was running 52psi at the rail).
>> > I
>> >upgraded
>> >> to 24lb SVO injectors based on everyone's recommendations.  Well,
>> >with the
>> >> 24's I was seeing almost 90% DCs at 6500rpms.  Those injectors 
>were
>> >on my
>> >> car for only an hour before I ordered a set of 30's.  The 30's 
>have
>> >acceptable
>> >> DCs ... in the order of 77% at 6500rpms ... and, the car idles 
>great.
>> > I
>> >> have the injector constant set to 33lb/hr in the PROM and I am 
>running
>> >45psi
>> >> at the rail.
>> >>
>> >> I do remember that at 4500rpms my injector pulse width stayed pretty
>> >static
>> >> until up to 6500rpms.  The fact that the RPMs were increasing and
>> >the IPW
>> >> remained the same caused the DC to rise substantially.
>> >>
>> >> My butt-o-meter is very inaccurate.  You're talking with someone 
>who
>> >couldn't
>> >> tell too much of a difference after swapping heads/cam.  But, with
>> >the new
>> >> SVO injectors (30lb) I noticed a difference in the upper RPMs. 
> If
>> >I get
>> >> to the track soon I might be able to prove it :-)
>> >>
>> >> Tim
>> >>
>> >> At Thu, 5 Oct 2000 10:00:52 -0400, "Dave Zug." <dzug at delanet.com>
>> >wrote:
>> >>
>> >> >
>> >> >To clarify, What Pulse width (in Ms) are you calling 100% DC  
>at
>> >4500
>> >> >RPM?
>> >> >
>> >> >Were your PW's constantly INCREASING as RPM went up?
>> >> >
>> >> >My 383 CI (360hp thereabouts, almost same cam as yours- less flow
>> >above
>> >> >5500
>> >> >though, stock lower intake) uses stock 22# and stock FP almost,
> hits
>> >> >85%
>> >> >static for a BRIEF moment after the shifts. o2's still on the 
>rich
>> >side
>> >> >according to GM sensor (093) , and plug condition backs it up.
>> >> >
>> >> >This is not meant as evidence contrary to your observations - 
>just
>> >more
>> >> >info
>> >> >to add to the collection.,.. mine and yours.
>> >> >
>> >> >----- Original Message -----
>> >> >From: <timsiford at hushmail.com>
>> >> >To: <gmecm at diy-efi.org>
>> >> >Sent: Thursday, October 05, 2000 9:49 AM
>> >> >Subject: Re: Nother thought
>> >> >
>> >> >
>> >> >> I was running the stock 22lb injectors on my IROC (218cam, AFR
>> >heads,
>> >> >MiniRam)
>> >> >> for about 3000 miles before swapping to 30lb injectors.  At 
>WOT
>> >I
>> >> >would
>> >> >> reach 100% DC by 4500rpms.  I would continue to shift at 6500.
>> > This
>> >> >is
>> >> >>  great example of how the stock O2 cannot be used for tuning.
>> >The
>> >> >O2
>> >> >volts
>> >> >> were approx 830mV and greater throughout the entire RPM range 
>even
>> >> >though
>> >> >> I was hitting 100% DC.  After switching to 30's I noticed
>significant
>> >> >improvement.
>> >> >>  The stock 22lb injectors never falterered and still function 
>great.
>> >> >>
>> >> >> Tim
>> >> >>
>> >> >> At Wed, 4 Oct 2000 23:22:33 -0400, "Bruce Plecan"
><nacelp at bright.net>
>> >> >wrote:
>> >> >>
>> >> >> >
>> >> >> >Anybody have any info., about the extended effects of running
>> >really
>> >> >> >high
>> >> >> >DCs on injector drivers?.
>> >> >> >Just thinking, out loud.
>> >> >> >Just with all the hours of running stuff here, I can't find 
>any
>> >real
>> >> >> >reason
>> >> >> >for for the 85% DC, as applied to a street car.
>> >> >> >Just maybe do to worry about a worse case thermal situation,
> and
>> >> >portecting
>> >> >> >the devices?.
>> >> >> >Or maybe just a ol wifes tale....
>> >> >> >Bruce
>> >> >> >
>> >> >> >
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