Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b6) with ESMTP id 241330 for flyrotary@lancaironline.net; Fri, 02 Jul 2004 22:19:28 -0400 Received: from EDWARD (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i632IeiB018885 for ; Fri, 2 Jul 2004 22:18:41 -0400 (EDT) Message-ID: <000c01c460a4$108018f0$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EC2 programming Date: Fri, 2 Jul 2004 22:18:43 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01C46082.89354080" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0009_01C46082.89354080 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sounds like you have the problem identified, John. It certainly could = be the problem. The Saturation type injectors are generally around = 12-16 ohms resistance and the peak and hold around 2-5 ohms. So the EC2 = would provide a nominal 14/14 =3D 1 amps to the staturation type, but = with out the 5 ohm resistor and using peak and hold with lower = resistance the current 14/3.5 =3D 4 amps taking the middle resistance = value of the range of each type injector. With the resistor they should = see approx 14/8.5 =3D 1.5 - 2 amps. The peak and hold tend to open faster than the saturation type so you do = not need as much injector-on time to get the same fuel flow. In fact if = the Peak and Hold are driven with an injector pulse duration calculated = for a statuation type injector then you would get more fuel flow for the = same pulse duration. According to MSD the Satuation types take approx 2 milliseconds to open = whereas the Peak and hold only take 1.5 milliseconds. Back of an envelope calcuations shows that With an pulse duration of = around 4 milliseonds typical, then the 2 -1.5 =3D 0.5 milliseconds = difference would equate to a 0.5/4 =3D 12.5% more fuel flow = approximately. But since your peak and hold were being overdrive with = current (without the 5 ohm resistor) the difference may have been even = more. Those suckers probably jumped from closed to full open in 1 msec = or less {:>_ with that 4 amp kick. That is one thing about these Mazda Rx-7 injectors, its really easy to = get caught if you don't actually measure the resistance. I have = satuation type injectors with the same color electrical connector AND = same part number stamped on the electrical connector but one set are = peak and hold and the other 4 are saturation type. Error in = manufacturing?? don't know. Also, the 560 cc saturation injectors came = with a purple connector and an unpainted (silver) body. Guess, what, = some folks have cleaned off the scratched up black paint off the 460 cc = injectors and with a faded red connector - it can (and has been) = mistaken for the 560 cc injector. So you gotta be careful. Ed =20 Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: John Slade=20 To: Rotary motors in aircraft=20 Sent: Friday, July 02, 2004 9:24 PM Subject: [FlyRotary] Re: EC2 programming I think I found the problem.... or at least Tracy did. He realized = that my symptoms would be a lot like what you'd get if you used peak & = hold resistors without the 5 ohm resistors. =20 About 2 years ago I got 2 purple 550cc injectors from Bruce. They were = Saturation type, so I didn't need resistors.=20 A year later I got two more from the local Mazda shop for the = secondaries. They were purple, so I ASSumed they were the same. I tested = them tonight and found that they're the peak & hold type. Without = resistors they get too much current and they don't open and close as the = EC2 expects. Result - uncontrollable mixture problems.=20 OK, so how do I get 2 * 5 ohm 25 watt resistors on a holiday Saturday? John (mix & match) Slade ------=_NextPart_000_0009_01C46082.89354080 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Sounds like you have the problem = identified,=20 John.  It certainly could be the problem.  The Saturation type = injectors are generally around 12-16 ohms resistance and the peak and = hold=20 around 2-5 ohms.  So the EC2 would provide a nominal 14/14 =3D 1 = amps to the=20 staturation type, but with out the 5 ohm resistor and using peak and = hold with=20 lower resistance the current 14/3.5 =3D 4 amps taking the middle = resistance value=20 of the range of each type injector.  With the resistor they should = see=20 approx 14/8.5 =3D 1.5 - 2 amps.
 
The peak and hold tend to = open faster than the=20 saturation type so you do not need as much injector-on time to get the = same fuel=20 flow.  In fact if the Peak and Hold are driven with an injector = pulse=20 duration calculated for a statuation type injector then you would get = more fuel=20 flow for the same pulse duration.
 
According to MSD the Satuation types = take approx 2=20 milliseconds to open whereas the Peak and hold only take 1.5=20 milliseconds.
 
Back of an envelope calcuations shows = that With an=20 pulse duration of around 4 milliseonds = typical, then  the=20  2 -1.5 =3D 0.5 milliseconds difference would equate to a 0.5/4 =3D = 12.5% more=20 fuel flow approximately.  But since your peak and hold were = being=20 overdrive with current (without the 5 ohm resistor) the = difference may=20 have been even more.  Those suckers probably jumped from closed to = full=20 open in 1 msec or less {:>_ with that 4 amp kick.
 
That is one thing about = these Mazda=20 Rx-7 injectors, its really easy to get caught if you don't = actually=20 measure the resistance.  I have satuation type injectors with the = same=20 color electrical connector AND same part number stamped on = the electrical=20 connector but one set are peak and hold and the other 4 are saturation=20 type.  Error in manufacturing?? don't know.  Also, the 560=20 cc saturation injectors came with a purple connector and an = unpainted=20 (silver) body.  Guess, what, some folks have cleaned off the = scratched up=20 black paint off the 460 cc injectors and with a faded red connector = - it=20 can (and has been) mistaken for the 560 cc injector.  So you gotta = be=20 careful.
 
Ed
  
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 John=20 Slade
Sent: Friday, July 02, 2004 = 9:24 PM
Subject: [FlyRotary] Re: EC2=20 programming

I=20 think I found the problem.... or at least Tracy did. He realized that = my=20 symptoms would be a lot like what you'd get if you used peak & = hold=20 resistors without the 5 ohm resistors. 
 
About 2 years ago I got 2 purple 550cc = injectors from=20 Bruce. They were Saturation type, so I didn't need resistors.=20
A=20 year later I got two more from the local Mazda shop for the = secondaries. They=20 were purple, so I ASSumed they were the same. I tested them = tonight and=20 found that they're the peak & hold type. Without resistors = they get=20 too much current and they don't open and close as the EC2 expects. = Result -=20 uncontrollable mixture problems.
 
OK,=20 so how do I get 2 * 5 ohm 25 watt resistors on a holiday=20 Saturday?
 
John=20 (mix & match) Slade =
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