Return-Path: <13brv3@bellsouth.net> Received: from imf16aec.mail.bellsouth.net ([205.152.59.64] verified) by logan.com (CommuniGate Pro SMTP 4.2b6) with ESMTP id 190769 for flyrotary@lancaironline.net; Sun, 20 Jun 2004 09:54:34 -0400 Received: from rad ([65.6.194.9]) by imf16aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040620135404.GNXA1705.imf16aec.mail.bellsouth.net@rad> for ; Sun, 20 Jun 2004 09:54:04 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: smaller injectors, same idle Date: Sun, 20 Jun 2004 08:54:05 -0500 Message-ID: <01a701c456ce$0d4824a0$6001a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_01A8_01C456A4.24721CA0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_01A8_01C456A4.24721CA0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable That does seem strange that the smaller injectors produce the same idle results. Are you 100% sure that those are the injectors that are = running at low speed ? Maybe the primary and secondary are reversed ? =20 =20 I'm about 99% sure it's running on the correct injectors, but I've also turned off the primary switch, and run on the secondaries. It has = always idles slightly better on the MSD injectors, perhaps because they behave leaner for some reason. =20 =20 With the 550 turbo injectors as primary, and 525 MSD injectors as = secondary, switching between the two at low throttle requires about 180 degree turn = of the mixture knob. In other words, say I'm running on the 550 Mazda injectors, and the mixture is set to 12:00. If I turn off the primary injector switch, I'm now running on the MSD injectors, and the mixture = is way lean. I have to turn the mixture knob to the CW limit to get back = to about the same mixture that I had at 12:00 with Mazda injectors. When = I had larger primaries than secondaries, I could at least imagine that's = why the secondaries seemed leaner. The baffling part is that this = behavior is unchanged with the new injectors. In other words, the primaries are now smaller (460) than the secondaries (525), but the secondaries still seem = to be much leaner. =20 I'll probably order the new plastic diverter thingies that go in the = block, so I can install the '88 NA square plug injectors as primaries. I don't suspect that will change anything mixture-wise though. I sure wish I = could install the MSD injectors in the block, and I may have to look at that again. =20 =20 Also how is the fuel pressure ? If it is too high, maybe it is running = very rich on both the large and small injectors. Does you fuel regulator = have a MAP reference so that it reduces fuel pressure at lower power settings ? = =20 The fuel pressure is 42 psi when the engine is not running, and the regulator does have a MAP reference. I've never really watched it while running to see if it changed though. I just scribbled that on my note = for today. =20 My engine is now running pretty good and idles very well at 1000 RPMs. = My only rough spot is somewhere around 1500, it stumbles occasionally. = Mainly when the engine is hot. Now if I could just get my temperatures down another 15 degrees I'd have it made. =20 =20 Pity I can't trade you 15 degrees for a better idle :-) =20 =20 Hey Tracy, how well does your engine idle below 1500? Porting the = engine should have some effect on the idle quality, and since Bruce ported both = of our engines, I would suspect they'll be the same. Also, is anyone with = a ported engine getting good idle at 1000 or less? I can live with 1500, especially when I go to the 2.85 gear drive. The bigger problem now is = that I can't get the B controller to idle at even 1500. =20 =20 Cheers, Rusty (FD goes on Auto Trader this week)=20 ------=_NextPart_000_01A8_01C456A4.24721CA0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
That=20 does seem strange that the smaller injectors produce the same idle = results.  Are you 100% sure that those = are the=20 injectors that are running at low speed ? Maybe the primary and = secondary are=20 reversed ?   
 
I'm about 99% sure it's running on the correct injectors, but = I've also=20 turned off the primary switch, and run on the secondaries.  It has=20 always idles slightly better on the MSD injectors, perhaps because = they=20 behave leaner for some=20 reason.  
 
With the 550 turbo injectors as primary, and 525 MSD = injectors as=20 secondary, switching between the two at low throttle requires about = 180=20 degree turn of the mixture knob.  In other words, say I'm = running on=20 the 550 Mazda injectors, and the mixture is set to 12:00.  If I = turn off=20 the primary injector switch, I'm now running on the MSD injectors, = and the=20 mixture is way lean.  I have to turn the mixture knob to the CW = limit to=20 get back to about the same mixture that I had at 12:00 with Mazda=20 injectors.   When I = had=20 larger primaries than secondaries, I could at least imagine that's = why the=20 secondaries seemed leaner.    The baffling part is that = this=20 behavior is unchanged with the new injectors.  In other words, the=20 primaries are now smaller (460) than the secondaries (525), = but the=20 secondaries still seem to be much=20 leaner.
 
I'll probably order the new plastic diverter thingies that go = in the=20 block, so I can install the '88 NA square plug injectors as=20 primaries.  I don't suspect that will change anything mixture-wise=20 though.  I sure wish I could install the MSD injectors in = the block,=20 and I may have to look at that again.    =20
 

Also how=20 is the fuel pressure ?  If = it is too=20 high, maybe it is running very rich on both the large and small = injectors.  Does you fuel regulator have a = MAP=20 reference so that it reduces fuel pressure at lower power settings = ? 

&nbs= p;

The fuel = pressure is=20 42 psi when the engine is not running, and the regulator does have a MAP = reference.  I've never really watched it while running to see = if it=20 changed though.  I just scribbled that on my note for=20 today.

 

My=20 engine is now running pretty good and idles very well at 1000 RPMs.  My only rough spot is = somewhere around=20 1500, it stumbles occasionally. =20 Mainly when the engine is hot.   Now if I could just get = my=20 temperatures down another 15 degrees I’d have it=20 made.

 

 

Pity I can't trade you 15 = degrees for=20 a better idle = :-)   

 

Hey Tracy, how well does your = engine idle=20 below 1500?  Porting the engine should have some effect on the idle = quality, and since Bruce ported both of our engines, I would = suspect=20 they'll be the same.  Also, is anyone with a ported engine getting = good=20 idle at 1000 or less?  I can live with 1500, especially = when I go=20 to the 2.85 gear drive.  The bigger problem now is that I = can't get=20 the B controller to idle at even=20 1500.  

 

Cheers,

Rusty (FD goes on Auto = Trader this=20 week) 

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