Return-Path: Received: from fed1rmmtao07.cox.net ([68.230.241.32] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 389191 for flyrotary@lancaironline.net; Wed, 01 Sep 2004 20:46:27 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.32; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao07.cox.net (InterMail vM.6.01.03.02.01 201-2131-111-104-103-20040709) with ESMTP id <20040902004552.PXCA4909.fed1rmmtao07.cox.net@BigAl> for ; Wed, 1 Sep 2004 20:45:52 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: MAP filter Date: Wed, 1 Sep 2004 17:45:55 -0700 Message-ID: <000001c49086$34f782b0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C4904B.889B1BB0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C4904B.889B1BB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable >> > > Al, been there, doing that with the RC thing - .04"/1mm and a cheap > generic plastic fuel filter work very well at all RPM and load ranges. = I > can send you some datalogs if you wish. If the orifice is too small, = the > ECU has to wait a few tenths of a second for an accurate MAP signal. > This causes a short period of enleanment and a momentary stumble. It's > actually the flow in and out of the capacitance that you're = restricting, > not the extremely miniscule flow that the sensor diaphragm generates, = if > any. I think most MAP sensors are strain gauges. You want > Manifold->R->C->MAP sensor as your sequence of parts. I've spent many > hours getting this right by trial and error and have extremely smooth > sensor response even at .01 second data logging intervals at 800 rpm = idle. > -Mike > Can=92t argue with success. Yes, you would not want a very small=20 restrictor upstream from the accumulator. My logic was telling me that=20 the most effective pulse dampening with the least effect on response=20 time would be a smaller restrictor on the controller side. But logic=20 doesn=92t always match reality, and I suppose that option was one of=20 your trials. =20 What application and ECU are you using? Do you suppose it is=20 independent of those things? > I'm running a streetported 12A rotary in an '83 RX-7 using the=20 MegaSquirt fuel only ECU, Weber Alpha 2x50mm bodies (very similar to the = TWM bodies) w/ an approximately 19" tract from the rotor face in each=20 port to the end of the TB intake bell. I'm no EE but from what I can=20 tell, most pressure sensors up to the job of reporting MAP are pretty=20 much the same as far as operating theory. A Motorola MPX4250 is the=20 sensor used in my app. Another thing I'd like to mention is that I also=20 have approximately 6' of 1/4" line from the manifold to the RC/MAP=20 sensor combo so there's definitely some extra volume from the hose run. =20 This could be quite a difference =96 =BC=94 i.d that long is about 3.5 = cu. in. upstream from the restrictor. How big is the filter? =20 I believe that each application/install has it's variables and no one=20 solution will be perfect for everybody though we can all learn from each = other. Well said. =20 My setup had a short run of about 3=92 if 1/8=94 i.d. line, and the = running was rough. So far the best results I=92ve had was on the first quick try = where I teed together the A & B controller lines with a 5/32 plastic T, then = added in about 18=94 of 5/16=94 i.d. vinyl tube from there to the sensor. The = T is a restrictor of sorts because it has an i.d. of about .065. So it was = line, restrictor, volume (approx. 1.4 cu in.). Unfortunately, the test was = very short because I was also measuring oil drain from the redrive, and the engine had not warmed up. But I had about 15 seconds of completely = smooth running at 1600 rpm before shutting down. I was thrilled because up = that point I had nothing but roughness. =20 I bought a small plastic fuel filter, made an orifice in one end by = filling the inlet with about =BE=94 of epoxy microglass, and drilling it out to = .063 (smallest drill I had). The filter has roughly 1 cu. in. of volume. I = tried this in place of the 18=94 of vinyl tube with the orifice toward the = manifold. This was better than no filter, but still rough. I then reversed it = placing the orifice on the end toward the sensor. Seemed to run a little = smoother, but at little lean of optimum mixture it got into kind of a slow surging behavior which I had not experienced before. Still no joy. =20 This may all be a bit meaningless since during these runs the engine was warming up. When I went back to the first 5/16=94 tube setup I could = not get complete smoothness at 1600; maybe because this time the engine was = warm.=20 =20 It=92s a guessing game, and what is needed is an oscilloscope on the MAP sensor output.=20 =20 Al ------=_NextPart_000_0001_01C4904B.889B1BB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

>>

>

> Al, been there, doing that with the RC thing - .04"/1mm and a = cheap

> generic plastic fuel filter work very well at all RPM and load ranges. = I

> can send you some datalogs if you wish. If the orifice is too small, = the

> ECU has to wait a few tenths of a second for an accurate MAP = signal.

> This causes a short period of enleanment and a momentary stumble. = It's

> actually the flow in and out of the capacitance that you're = restricting,

> not the extremely miniscule flow that the sensor diaphragm generates, = if

> any. I think most MAP sensors are strain gauges. You = want

> Manifold->R->C->MAP sensor as your sequence of parts. I've = spent many

> hours getting this right by trial and error and have extremely = smooth

> sensor response even at .01 second data logging intervals at 800 rpm = idle.

> -Mike

>

Can’t argue with success. Yes, you would not = want a very small

=A0restrictor upstream from the accumulator. My = logic was telling me that

=A0the most effective pulse dampening with the = least effect on response

=A0time would be a smaller restrictor on the = controller side. But logic

=A0doesn’t always match reality, and I = suppose that option was one of

=A0your trials.

 

What application and ECU are you using? Do you = suppose it is

independent of those things?

>

I'm running a streetported 12A rotary in an '83 RX-7 using the =

MegaSquirt fuel only ECU, Weber Alpha 2x50mm bodies (very similar to the =

TWM bodies) w/ an approximately 19" tract from the rotor face in each =

port to the end of the TB intake bell. I'm no EE but from what I can =

tell, most pressure sensors up to the job of reporting MAP are pretty =

much the same as far as operating theory. A Motorola MPX4250 is the =

sensor used in my app. Another thing I'd like to mention is that I also =

have approximately 6' of 1/4" line from the manifold to the RC/MAP =

sensor combo so there's definitely some extra volume from the hose = run.

 

This could be = quite a difference – =BC” i.d that long is about 3.5 cu. in. = upstream from the restrictor.=A0 How big is the filter?

=A0

I believe that each application/install has it's variables and no one =

solution will be perfect for everybody though we can all learn from each =

other.=A0 Well said.

 

My setup had a = short run of about 3’ if 1/8” i.d. line, and the running was = rough.=A0 So far the best results I’ve had was on the first quick try where I = teed together the A & B controller lines with a 5/32 plastic T, then = added in about 18” of 5/16” i.d. vinyl tube from there to the = sensor.=A0 The T is a restrictor of sorts because it has an i.d. of about .065. =A0So it = was line, restrictor, volume (approx. 1.4 cu in.).=A0 Unfortunately, the test was = very short because I was also measuring oil drain from the redrive, and the = engine had not warmed up. =A0But I had about 15 seconds of completely smooth = running at 1600 rpm before shutting down.=A0 I was thrilled because up that point I = had nothing but roughness.

 <= /font>

I bought a = small plastic fuel filter, made an orifice in one end by filling the inlet = with about =BE” of epoxy microglass, and drilling it out to .063 (smallest = drill I had). The filter has roughly 1 cu. in. of volume. =A0I tried this in = place of the 18” of vinyl tube with the orifice toward the manifold. =A0This = was better than no filter, but still rough.=A0 I then reversed it placing the = orifice on the end toward the sensor. =A0Seemed to run a little smoother, but at little = lean of optimum mixture it got into kind of a slow surging behavior which I had = not experienced before. =A0Still no joy.

 

This may all = be a bit meaningless since during these runs the engine was warming up.=A0 When I = went back to the first 5/16” tube setup I could not get complete = smoothness at 1600; maybe because this time the engine was warm.

 

It’s a = guessing game, and what is needed is an oscilloscope on the MAP sensor output. =

=A0

Al

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