X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 16 Dec 2007 16:19:06 -0500 Message-ID: X-Original-Return-Path: Received: from mtao05.charter.net ([209.225.8.179] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2600322 for lml@lancaironline.net; Sun, 16 Dec 2007 08:32:34 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.225.8.179; envelope-from=LHenney@charter.net Received: from aarprv06.charter.net ([10.20.200.76]) by mtao05.charter.net (InterMail vM.7.08.02.00 201-2186-121-20061213) with ESMTP id <20071216133148.SWLW20095.mtao05.charter.net@aarprv06.charter.net> for ; Sun, 16 Dec 2007 08:31:48 -0500 Received: from LHenneyLaptop ([24.182.195.198]) by aarprv06.charter.net with ESMTP id <20071216133147.DOHH14098.aarprv06.charter.net@LHenneyLaptop> for ; Sun, 16 Dec 2007 08:31:47 -0500 From: "LHenney" X-Original-To: "Lancair List" Subject: FW: GAMI Injectors - More questions for Walter X-Original-Date: Sun, 16 Dec 2007 07:30:48 -0600 X-Original-Message-ID: <000301c83fe8$03473520$650fa8c0@LHenneyLaptop> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C83FB5.B8ACC520" X-Mailer: Microsoft Office Outlook 11 Thread-Index: Acg/4x/Up824E7H2QlGfL7zAcs6oZAAAuekQ X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 X-Chzlrs: 0 This is a multi-part message in MIME format. ------=_NextPart_000_0004_01C83FB5.B8ACC520 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Fred Writes, =20 >Here is why I ask. If you have a good induction air inlet that is = getting a high percentage of the ram air pressure, and smaller cooling air inlet >ports that do a lesser job at recovering the ram pressure, then it is entirely possible that your manifold pressure is higher than the cooling = air >pressure surrounding the normally aspirated injectors. =20 =20 The overwhelming truth when I made my injector shrouded ram system was consistency. I believe it=92s not a question of how much delta P you = are generating but the fact that all cylinders receive consistent pressure. Remember, #2 on a Lyc is facing the ram while he #1 injector is blocked = by the cylinder, etc. Fred, this is not a do some testing thing. It is a = put it in and cry over how much leaner and smoother your engine will run. = This is the single most overwhelming improvement to my plane following my = Koger canopy shade, Spry shocks, ok, ok, and my 10:1 pistons, Catto Prop, etc = :-) Trust me I noticed improvement and I=92m not a real analytical guy. =20 And btw, this requires no fancy rails or expense. My neighbor just = through in a 3/8=94 tube feeding a couple reducing T=92s to =BC=94 lines. The = =BC=94 lines go to the injectors with a little collar and a couple O rings. You can = whittle out the collars or buy=92m from Airflow Performance. He=92d like to = sell you injectors too but I put my old Lyc injectors in the lathe and trimmed a = few thousandths and it all fits nice. =20 Larry Henney 2007 SARL Gold :-) N360LH =20 PS: Not an engineer but stayed at a Holiday Inn Express last = night=85=85. No, really! =20 =20 =20 _____ =20 From: Fred Moreno [mailto:fredmoreno@optusnet.com.au]=20 Sent: Saturday, December 15, 2007 8:00 AM To: lml@lancaironline.net Subject: GAMI Injectors - More questions for Walter =20 Many thanks to all that responded to my post. The discussion is most enlightening. And there is nothing like actual operational experience = to correct nebulous speculations. Thanks also to Walter who pointed out my fuzzy thinking that was blending atomization and vaporization. They are separate processes. =20 More questions:=20 =20 =20 1) The turbo injectors do not have screens like the NA injectors do. = They have air inlets from an upper deck reference line. Scott is using = those. =20 Do the turbo injectors have better air passages that allow them to do a better atomization job than the normally aspirated injectors, even when installed in a normally aspirated engine? Said another way, for the = same delta P do the screens on the NA injectors restrict air flow compared to = the turbo injectors with their air shroud and supply line? =20 2) The delta air pressure is most important at WOT... A delta P of 3" = Hg is adequate to result in excellent fuel atomization to aid in vaporization. More pressure does not necessarily make things better. =20 OK, let=92s see what might be possible with a normally aspirated engine. = The ram pressure at 200 KIAS is about 2 inches Hg, give or take. Let=92s = assume you get 100% of this for the fuel injector air flow using a nice pitot = tube set up like Scott=92s. And let=92s assume that the engine induction = system gets about 75% of this for a little manifold pressure boost at WOT, this = being a typical figure for a good diffuser taking in induction air. Then the difference of 0.5 inch Hg is available for atomization. This is clearly better than zero, but a lot less than 3=94 Hg. So might one make = further improvements in atomization by somehow boosting the injector air flow? = (The mind boggles=85.) Or is 0.5 inches Hg enough at WOT cruise? =20 3) Mark wrote: I cobbled together a similar arrangement to supply ram = air to the injector shrouds. I can't say I see a bunch of speed improvement as = I'm not one for careful analytical testing. I can say - the improvement in engine smoothness when running LOP in high altitude cruise is DRAMATIC. =20 Please tell us more about your set up, Mark. Is your engine induction = air coming from a separate scoop than the cooling air? Does your cooling = air come through small inlet ports in the cowl? Which engine? =20 Here is why I ask. If you have a good induction air inlet that is = getting a high percentage of the ram air pressure, and smaller cooling air inlet = ports that do a lesser job at recovering the ram pressure, then it is entirely possible that your manifold pressure is higher than the cooling air = pressure surrounding the normally aspirated injectors. =20 =20 This =93reverse pressure delta P=94 would reverse the injector air flow, = and may cause the blue staining that was mentioned around the NA injectors. It would also cause poor atomization that becomes most evident operating = LOP. =20 =20 But if you now add a pitot set up like Scott=92s, you get more air = pressure fed to the injectors, and you restore the injector air flow to the way = it should be =96 air flowing into the intake manifold instead of out of it. Atomization improves and your ability to lean further improves as a = result. Do you think that may have been happening on your plane? =20 The reason I persist on this topic is that for those of us using = IO-550=92s in Legacy or ES (or rare birds like me, in an LIV) where induction air is coming from inside the cowl, there may be a lot to learn that could = improve our cruise efficiency, particularly worthwhile with 5 buck avgas.=20 =20 =20 I see another test program looming on the horizon=85.. =20 =20 Still Curious Fred ------=_NextPart_000_0004_01C83FB5.B8ACC520 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Fred = Writes,

 

>Here is why = I ask.  If you have a good induction air inlet that is getting = a high percentage of the ram air pressure, and smaller cooling air inlet = >ports that do a lesser job at recovering the ram pressure, then it is entirely possible that your manifold pressure is higher than the cooling air = >pressure surrounding the normally aspirated injectors.  =

 

The = overwhelming truth when I made my injector shrouded ram system was consistency.  I = believe it’s not a question of how much delta P you are generating but the fact that = all cylinders receive consistent pressure.  Remember, #2 on a Lyc is = facing the ram while he #1 injector is blocked by the cylinder, etc.  = Fred, this is not a do some testing thing.  It is a put it in and cry over how = much leaner and smoother your engine will run.  This is the single most overwhelming improvement to my plane following my Koger canopy shade, = Spry shocks,  ok, ok, and my 10:1 pistons, Catto Prop, etc = J  Trust me I noticed = improvement and I’m not a real analytical guy.

 

And btw, this = requires no fancy rails or expense.  My neighbor just through in a = 3/8” tube feeding a couple reducing T’s to ¼” lines.  The = ¼” lines go to the injectors with a little collar and a couple O = rings.  You can whittle out the collars or buy’m from Airflow = Performance.  He’d like to sell you injectors too but I put my old Lyc injectors in the = lathe and trimmed a few thousandths and it all fits = nice.

 

Larry = Henney

2007 SARL Gold = J

N360LH

 

PS:  Not = an engineer but stayed at a Holiday Inn Express last night……. = No, really!

 

 

 

From: Fred = Moreno [mailto:fredmoreno@optusnet.com.au]
Sent: Saturday, December = 15, 2007 8:00 AM
To: = lml@lancaironline.net
Subject: GAMI Injectors - = More questions for Walter

 

Many thanks to = all that responded to my post.  The discussion is most enlightening.  = And there is nothing like actual operational experience to correct nebulous speculations.  Thanks also to Walter who pointed out my fuzzy = thinking that was blending atomization and vaporization.  They are separate processes.

 

More questions: =

 

 

1)  The turbo = injectors do not have screens like the NA injectors do.  They have air inlets = from an upper deck reference line.  Scott is using = those.

 

Do the turbo = injectors have better air passages that allow them to do a better atomization job = than the normally aspirated injectors, even when installed in a normally = aspirated engine?  Said another way, for the same delta P do the screens on = the NA injectors restrict air flow compared to the turbo injectors with their = air shroud and supply line?

 

2) The delta air = pressure is most important at WOT...  A delta P of 3" Hg is adequate to = result in excellent fuel atomization to aid in vaporization.  More pressure = does not necessarily make things better.

 

OK, let’s see = what might be possible with a normally aspirated engine.  The ram pressure at = 200 KIAS is about 2 inches Hg, give or take.  Let’s assume you = get 100% of this for the fuel injector air flow using a nice pitot tube set up = like Scott’s.  And let’s assume that the engine induction = system gets about 75% of this for a little manifold pressure boost at WOT, this = being a typical figure for a good diffuser taking in induction air.  Then = the difference of 0.5 inch Hg is available for atomization.  This is = clearly better than zero, but a lot less than 3” Hg.  So might one = make further improvements in atomization by somehow boosting the injector air = flow?  (The mind boggles….)  Or is 0.5 inches Hg enough at WOT cruise?

 

3) Mark wrote: = I cobbled together a similar arrangement = to supply ram air to the injector shrouds. I can't say I see a bunch of speed improvement as I'm not = one for careful analytical testing.  I can say - the improvement in engine smoothness when running LOP in high altitude cruise is = DRAMATIC.

 

Please tell us = more about your set up, Mark.  Is your engine induction air coming from = a separate scoop than the cooling air?  Does your cooling air come = through small inlet ports in the cowl?  Which engine?

 

Here is why I = ask.  If you have a good induction air inlet that is getting a high = percentage of the ram air pressure, and smaller cooling air inlet ports that = do a lesser job at recovering the ram pressure, then it is entirely possible = that your manifold pressure is higher than the cooling air pressure = surrounding the normally aspirated injectors. 

 

This = “reverse pressure delta P” would reverse the injector air flow, and may = cause the blue staining that was mentioned around the NA injectors.  It would = also cause poor atomization that becomes most evident operating LOP.  =

 

But if you now = add a pitot set up like Scott’s, you get more air pressure fed to the injectors, and you restore the injector air flow to the way it should be – air flowing into the intake manifold instead of out of it.  Atomization improves and your ability to lean further improves as a result.  Do you think that may have been happening on your = plane?

 

The reason I = persist on this topic is that for those of us using IO-550’s in Legacy or ES = (or rare birds like me, in an LIV) where induction air is coming from = inside the cowl, there may be a lot to learn that could improve our cruise = efficiency, particularly worthwhile with 5 buck avgas.

 

 

I see another = test program looming on the horizon…..

 

 

Still Curious = Fred

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