X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 950881 for flyrotary@lancaironline.net; Fri, 20 May 2005 08:32:29 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.101; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-065-188-083-049.carolina.res.rr.com [65.188.83.49]) by ms-smtp-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j4KCVe0W017463 for ; Fri, 20 May 2005 08:31:41 -0400 (EDT) Message-ID: <000e01c55d37$e46d25f0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: More MAP measurement questions Date: Fri, 20 May 2005 08:31:48 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000B_01C55D16.5D13F5A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000B_01C55D16.5D13F5A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageHi George, No experience with the EM2, but the EC2 is great. Dual CPUs, so you = have a degree of redundancy - but, even better you can play with two = different fuel maps with one stored for A controller and the other for B = controller. I leave one with Tracy's stock setting and play with the = other, that way I always have one fuel map that will run the engine to = switch to in case I really screw up something on one controller. Ed ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Friday, May 20, 2005 4:29 AM Subject: [FlyRotary] Re: More MAP measurement questions Ed, Rusty, Bill, Anyone. Here's another question - having little knowledge in the area, I'm = considering Tracy's ECU and the EM2. What are your appreciations of the products. Is it the EM2 which provides the auto tune capability ? George (down under) Hi George, I'll give it a shot. The Ec2 basically determines how much fuel to = inject using two factors - MAP (Manifold Absolute Pressure) and OAT = which basically tells it how dense the air is that the engine is = ingesting from the manifold. The Ec2 then examines its memory settings = (a different Map - read further)programmed in its memory (which you can = adjust with a mixture knob) for that manifold pressure match. Since the = manifold pressure can vary from apporx 12" Hg to 30"Hg (non-turbo), = there are a series of memory locations generally also referred to as the = MAP (MAP in this case referring to a topological chart) of the fuel = settings. If you plot the fuel mixture settings against RPM and Pressure = it looks like a 2 dim map). So once it matches the manifold pressure = it senses through the manifold pressure sensors with the corresponding = memory location it extracts the injector timing for that MAP and sends = it on to the injectors (with corrections for air temp). The injectors fire once per revolution of the E shaft (which = corresponds to one face of an rotor, therefore, the faster the rpm the = more frequently the injectors fire. But, it basically provides the same = amount of fuel per revolution per specific manifold pressure (which of = course is controlled by the throttle setting and engine rpm) perhaps = adjusted for Ve and OAT. Manifold Absolute Pressure is also one parameter to determine how = well you induction system is working. At sea level the MAP is 29.92" = Hg. So when you open your throttle wide open, you would like to see = 29.92" Hg on the gauge. If you do not and see less than 29.92"Hg (at = sea level) then that implies there is a restriction in your intake and a = resulting pressure loss. Less pressure means less dense air in the = manifold which means less fuel can be burnt which means less power. =20 That is the reason Rusty is concerned about whether the MAP he is = seeing really reflects what his engine is seeing or some fluke of where = the sensing port is in the intake. Generally you would like to have = less that 1/2" of a pressure drop any more than that (if its real) and = you are starting to loose power potential. So if the drop is real then = Rusty probably wants to modify his intake to eliminate it - if its just = a fluke of where he is sensing it - then he does not need to go to the = trouble of designing and fabricating a new intake. =20 That's my take on it. Hope it helps. Ed ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Thursday, May 19, 2005 2:13 AM Subject: [FlyRotary] Re: More MAP measurement questions Al,Rusty and All, Excuse my ignorance here, I have absolutely no knowledge about how = ECU's work. I've heard people say that it reads MAP settings - so what = is a MAP, and if it's different because the pressure is different at = different places in the inlet, how can the computer calculate the inlet = charge and timing. I'm confused! George ( down under) Greetings, I'm working on a new theory about my low MAP reading. The = theory is that this isn't a problem at all, but rather a difference in = the way it's being measured. =20 What's new about this theory? This is what I was telling you a = week or two ago. J I apologize for lack of clarity, causing you to have to = re-invent this theory. Al (Also running TWM TB) The TWM TB has a MAP port about 4 inches past the entrance of = the TB throat. That means I'm measuring the air pressure on the = suction side of the largest restriction in the system (from wide open = space, to 41mm tube). Since there's no significant restriction = downstream from the TB, I would guess that I could measure the MAP at = the inlet of the side housing, and wouldn't find it significantly lower = than what I'm seeing in the TWM TB. In other words, I'm measuring the = worst possible MAP, which is the suction side. =20 From what I understand, the typical (if there is such a thing) = intake has a large TB, feeding into an open plenum, then into the = smaller runners that go to the engine. If I'm not mistaken, virtually = everyone is measuring their MAP in the open plenum, before the air has = to enter the smaller runners to go to the engine. In other words, the = people who are reading 30" are doing it on the pressure side of the = largest restriction. =20 I could babble on about this, but my point is to ask where = others are measuring their MAP (turbo folks need not apply). You'll = also have to give a general description of your intake layout. I = already know that Ed and Tracy are using the "typical" situation. Is = anyone measuring MAP in the runner to the engine? =20 Cheers, Rusty (duty calls...) =20 ------=_NextPart_000_000B_01C55D16.5D13F5A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Hi George,
 
No experience with the EM2, but the EC2 is = great. =20 Dual CPUs, so you have a degree of redundancy - but, even better you can = play=20 with two different fuel maps with one stored for A controller and the = other for=20 B controller.  I leave one with Tracy's stock setting and play with = the=20 other, that way I always have one fuel map that will run the engine to = switch to=20 in case I really screw up something on one controller.
 
Ed
----- Original Message -----
From:=20 George=20 Lendich
Sent: Friday, May 20, 2005 4:29 = AM
Subject: [FlyRotary] Re: More = MAP=20 measurement questions

Ed, Rusty, Bill, Anyone.
Here's another question - having = little knowledge=20 in the area, I'm considering Tracy's ECU and the = EM2.
What are your appreciations of the=20 products.
Is it the EM2 which provides the = auto tune=20 capability ?
George (down under)
Hi George,
 
I'll give it a shot.  The Ec2 basically = determines how much fuel to inject using two factors - MAP (Manifold = Absolute Pressure) and OAT which basically tells it how dense the = air is=20 that the engine is ingesting from the manifold.  The Ec2 then=20 examines its memory settings (a different Map - read=20 further)programmed  in its memory (which you can adjust with a = mixture=20 knob) for that manifold pressure match.  Since the manifold = pressure=20 can vary from apporx 12" Hg to 30"Hg (non-turbo), there are a series = of=20 memory locations generally also referred to as the MAP (MAP in this = case=20 referring to a topological chart) of the fuel settings. If you plot = the fuel=20 mixture settings against RPM and Pressure it looks like a 2 dim = map).    So once it matches the manifold pressure it = senses=20 through the manifold pressure sensors with the corresponding memory = location=20 it extracts the injector timing for that MAP and sends it on to the=20 injectors (with corrections for air temp).
 
The injectors fire once per revolution of = the E shaft=20 (which corresponds to one face of an rotor, therefore, the faster = the rpm=20 the more frequently the injectors fire.  But, it basically = provides the=20 same amount of fuel per revolution per specific manifold pressure = (which of=20 course is controlled by the throttle setting and engine rpm) perhaps = adjusted for Ve and OAT.
 
Manifold Absolute Pressure is also one = parameter to=20 determine how well you induction system is working.  At sea = level the=20 MAP is 29.92" Hg.  So when you open your throttle wide open, = you would=20 like to see 29.92" Hg on the gauge.  If you do not and see less = than=20 29.92"Hg (at sea level) then that implies there is a restriction in = your=20 intake and a resulting pressure loss.  Less pressure means less = dense=20 air in the manifold which means less fuel can be burnt which means = less=20 power.  
 
That is the reason Rusty is concerned about = whether=20 the MAP he is seeing really reflects what his engine is seeing or = some fluke=20 of where the sensing port is in the intake.  Generally you = would like=20 to have less that 1/2" of a pressure drop any more than that (if its = real)=20 and you are starting to loose power potential.  So if the drop = is real=20 then Rusty probably wants to modify his intake to eliminate it - if = its just=20 a fluke of where he is sensing it - then he does not need to go to = the=20 trouble of designing and fabricating a new intake.  =
 
That's my take on it.  Hope it=20 helps.
 
Ed
----- Original Message ----- =
From:=20 George Lendich
To: Rotary motors in = aircraft=20
Sent: Thursday, May 19, = 2005 2:13=20 AM
Subject: [FlyRotary] Re: = More MAP=20 measurement questions

Al,Rusty and All,
Excuse my ignorance here, I have = absolutely=20 no knowledge about how ECU's work. I've heard people say that it = reads MAP=20 settings - so what is a MAP, and if it's different because the = pressure is=20 different at different places in the inlet, how can the computer = calculate=20 the inlet charge and timing.
I'm confused!
George ( down under)

 

Greetings,

 

I'm = working on=20 a new theory about my low MAP reading.  The theory is that = this=20 isn't a problem at all, but rather a difference in the way it's = being=20 measured. 

 

What=92s new=20 about this theory?  This is what I was telling you a week = or two=20 ago. J

I = apologize=20 for lack of clarity, causing you to have to re-invent this=20 theory.

 

Al = (Also=20 running TWM TB)

 

The = TWM TB has=20 a MAP port about 4 inches past the entrance of the TB=20 throat.   That means I'm measuring the air pressure on = the=20 suction side of the largest restriction in the system (from wide = open=20 space, to 41mm tube).   Since there's no significant=20 restriction downstream from the TB, I would guess that I = could=20 measure the MAP at the inlet of the side housing, and = wouldn't find=20 it significantly lower than what I'm seeing in the TWM = TB.  In=20 other words, I'm measuring the worst possible MAP, which = is the=20 suction side.    

 

From what I=20 understand, the typical (if there is such a thing) intake has a = large=20 TB, feeding into an open plenum, then into the smaller = runners that=20 go to the engine.  If I'm not mistaken, virtually = everyone is measuring their MAP in the open plenum, before the = air has=20 to enter the smaller runners to go to the = engine.  In=20 other words, the people who are reading 30" are doing it on = the=20 pressure side of the largest=20 restriction.  

 

I = could babble=20 on about this, but my point is to ask where others are measuring = their=20 MAP (turbo folks need not apply).  You'll also have to give = a=20 general description of your intake layout.   I already = know=20 that Ed and Tracy are using the "typical" situation.  Is = anyone=20 measuring MAP in the runner to the=20 engine?  

 

Cheers,

Rusty (duty=20 calls...)

 =20 =

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