Fuel pressure / Flow rate formula

[Walter Sherwin]

What's the title of the book you are
reading?....................................


-----Original Message-----
From: d houlton x0710 <tc75918 at hpr357.msc.az.boeing.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, November 17, 1998 1:03 PM
Subject: Re: Fuel pressure / Flow rate formula


>David A. Cooley wrote:
>>
>> At 10:34 AM 11/14/98 -0500, you wrote:
>> >
>> >-> That's a pretty blatant statement isn't it?  Are you saying that if I
>> >-> go over 40 psi it will fail, period?  Everything I've read suggests
>> >-> that an injector will still work up to 120 psi, but that you should
>> >-> set as a maximum around 90 psi.  At 70, it will still work just fine.
>>
>> Never said not to run them over 40psi even... some increase is ok, but
>> there comes a point (Found on the buick GN's for my reference) at about
>> 65-70PSI where the injector fails to open or close depending on the
design.
>> This is also the pressure differential across the injector, not
referenced
>> to atmospheric pressure... For a turbo'd engine with 20 psi in the
>> manifold, 80PSI fuel would not be unreasonable, as it is only 60PSI
across
>> the injector.
>> Later,
>> Dave
>
>
>Yup, what you said is below.
>
>> You crank up the FP too far past the rated pressure (in your case 40psi)
>> and 1 of 2 things happen... the injector gets held open by the fuel
>
>I missed the "too far" when I read it the first time and thought you were
>saying it'd fail if I went over 40 psi at all.  Sorry about that.
>
>I'm looking at a max of about 70 - maybe 80 psi depending on how I add
>extra fuel and it seems that most everyone agrees here that that'll be
>OK, especially for short durations.
>
>
>On a side note, I've been reading a new book I got on Nitrous Oxide.  It
>has a lot on working nitrous with fuel injection and has a section on fuel
>injectors and their capabilities.  It quotes RC Engineering and they
>apparently swear by the Lucas disk type injectors.  They say they can run
>at 85% - 95% duty cycle with no ill effects and can handle higher pressure
>much better than the pintle type.  They can also run a much shorter pulse
>at idle than a pintle type because of the smaller lift needed for a disk
>type.  Something like a .8 - .9 ms opening time for the disk vs 2 ms or
>so for the pintle.
>
>
>--Dan
>