X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf16aec.mail.bellsouth.net ([205.152.59.64] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1056453 for flyrotary@lancaironline.net; Sun, 02 Apr 2006 22:26:35 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.64; envelope-from=atlasyts@bellsouth.net Received: from ibm56aec.bellsouth.net ([65.11.149.236]) by imf16aec.mail.bellsouth.net with ESMTP id <20060403022549.FICL21187.imf16aec.mail.bellsouth.net@ibm56aec.bellsouth.net> for ; Sun, 2 Apr 2006 22:25:49 -0400 Received: from [192.168.0.100] (really [65.11.149.236]) by ibm56aec.bellsouth.net with ESMTP id <20060403022548.GEMU10721.ibm56aec.bellsouth.net@[192.168.0.100]> for ; Sun, 2 Apr 2006 22:25:48 -0400 Mime-Version: 1.0 (Apple Message framework v746.3) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-2-367738828 Message-Id: <0C0EF3A3-EEE0-431A-8730-56C61EE1F0E0@bellsouth.net> From: Bulent Aliev Subject: Re: [FlyRotary] Re: Erratic mixture Date: Sun, 2 Apr 2006 22:26:19 -0400 To: "Rotary motors in aircraft" X-Mailer: Apple Mail (2.746.3) --Apple-Mail-2-367738828 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed On Apr 2, 2006, at 9:28 PM, Russell Duffy wrote: > I have seen the FP changing > from 35 psi at low RPM to 50 psi at high boost? > > > Hi Buly, > > What you describe here is exactly how it's supposed to work, and > whether you believe it or not, it's making your tuning life > easier. Here's why... > > Think about how a fuel injector works. The fuel rail has a high > pressure in it, and the intake end of the injector is in a lower > pressure area. To actuate the injector, all you're doing is > opening it. The rate of fuel flow is controlled by the difference > between the pressure in the fuel rail, and the pressure in your > intake. > > As you can see, if you were to set your fuel pressure at a fixed > point, then run lots of boost, there would be very little flow > across the injector, because the differential pressure would be > low. This will make your injector appear to get smaller as boost > increases, and eventually you will go lean. Recall also that lean > + boost = rebuild :-( > > The whole idea of the rising rate fuel pressure regulator is to > keep the differential pressure close to the same, so the injector > flows the same rate of fuel regardless of the MAP. This makes it > easier for the engine computer to control idle to max boost mixtures. > > Cheers, > Rusty (Stopped to eat in Greenville AL in George's honor today ) > > > Thanks Rusty. That makes sense. Buly --Apple-Mail-2-367738828 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1


=

On Apr 2, 2006, at 9:28 PM, Russell Duffy = wrote:

I have seen the FP changing=A0
from = 35 psi at low RPM to 50 psi at high boost?

=A0
Hi Buly,
=A0
What you describe here is = exactly how it's supposed to work, and whether you believe it or not, = it's making your tuning life easier.=A0 Here's = why...
=A0
Think about = how a fuel injector works.=A0 The fuel rail has a high pressure in it, = and the intake end of the injector is in a lower pressure area.=A0 To = actuate the injector, all you're doing is opening it.=A0 The rate of = fuel flow is controlled by the difference between the pressure in the = fuel rail, and the pressure in your intake.=A0=A0
=
=A0
As you can see, if you were = to set your fuel pressure at a fixed point, then run lots of boost, = there would be very little flow across the injector, because the = differential pressure would be low.=A0 This will make your injector = appear to get smaller as boost increases, and eventually you will go = lean.=A0 Recall also that lean + boost =3D rebuild = :-(
=A0
The whole = idea of the rising rate fuel pressure regulator is to keep the = differential pressure close to the same, so the injector flows the same = rate of fuel regardless of the MAP.=A0=A0This makes it easier for the = engine computer to control idle to max boost = mixtures.
=A0
Cheers,
Rusty (Stopped to eat in=A0Greenville AL in George's = honor today <g>)
=A0
=
=A0


Thanks Rusty. That makes = sense.
Buly
= --Apple-Mail-2-367738828--