X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2338406 for flyrotary@lancaironline.net; Tue, 18 Sep 2007 17:45:09 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([24.74.103.61]) by cdptpa-omta01.mail.rr.com with SMTP id <20070918214430.BXKK4058.cdptpa-omta01.mail.rr.com@edward2> for ; Tue, 18 Sep 2007 21:44:30 +0000 Message-ID: <001001c7fa3d$31efb2d0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Strange Ignition? was [FlyRotary] Re: One for the guys that don't give up Date: Tue, 18 Sep 2007 17:45:13 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01C7FA1B.AA8F5690" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C7FA1B.AA8F5690 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, I did not catch what your ignition timing you have set when = encountering this. IF you set the ignition timing with little/no = advance/retard then you are around 25 deg BTDC. Here's some thoughts on what might be happening(just a SWAG). At lower = rpm generally require less ignition advance because the combustion has = more time to get completed, therefore the spark does not need to start = as early (less advance). However, as RPM increases the time for a = the combustion event becomes less and less which means you normally = would have your ignition advancing to compensate. I know you know = this, but bear with me. IF you ignition was advancing to the point that the leading plug spark = point was exceeding the optimum for those combustion conditions (rpm, = manifold pressure, ignition timing, etc), then the trailing spark which = lags might start to become the optimum spark in relation to the optimum = spark point. If so then I would expect the higher the rpm the more = influence the trailing spark might have. So what would you check. 1. I recall back a couple of years ago there was some discussion about = the stock pulleys on certain model year 13Bs being keyed different (bolt = hole pattern) on some year models such that the timing point was 10 deg = difference. I don't suppose you have two pulleys laying around that you = could compare the bolt hold pattern in the hub (match two of them up = with the holes and check the timing marks?) and then check hub on you = engine. A very long shot, but thought I would mention it. Because in = the unlikely event you would have a hub mismatch with your pulley then = of course, your timing would be 10 degrees off. 2. Unlikely as well, but I assume there is no change the coils (you = have six?) could be sequenced/hooked up improperly. I don't know what = the effect would be if the leading coils were sparking the trailing = plugs with the EC2. I know the timing split between the leading and = trailing is much less than in the automobile ignition timing - but I do = not believe it is zero. So the engine might well run, but might have = some unexpected things happening. 3. I have disabled my leading ignition while flying (it helps if you = encounter a bad case of SAG) and I notice no difference in power = although the EGT on both will increase about 150F from 1600-1750F. Do = you notice any change in your EGT when you do this? Well, that is about all of the wild theories I can come up with at the = moment. =20 ED =20 ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Tuesday, September 18, 2007 3:40 PM Subject: [FlyRotary] Re: One for the guys that don't give up The reason Tracy gave for the ECU not working was because of that = set-up, as his Vacuum pick -up is at the Plenum - something to do with = fluctuations within the tube, whereby the plenum was static or less = successful to wild fluctuations. George ( down under) I have accumulator and orifice which smooths the MAP nicely. Dave said: Besides a slight difference in the mixture necessary = between the 2 computers, both locations seem to work well. Dave: Mine works well also - except for the anomaly noted. I don't = know if you mean that yours specifically doesn't exhibit that = phenomenon? Al, was 35=B0 BTDC Tracys suggested timing? The 35o BTDC is the static setting specified in Tracy's manual; line = up the 2-point trigger wheel with the reluctors at that point. Quite frankly, I haven't tried the coil disable feature at high rpm = yet. So, I don't have an answer to your question. Heck, I can't even = get my auto-tune to work.=20 Mark; well, whenever you get that far, give it a shot and see what you = get. Good luck with the auto-tune. Does anyone else experience these symptoms? That's the question. Thanks, guys, Al OK; Mark; (or anybody). Since we both have 20Bs, and both use the = EC2 controller, maybe you have a clue for this one. I've brought this up = here before, but no solution. I have all the latest updates on the EC2, and I have double checked = the static timing set at 35o BTDC. From that point on the EC2 is = handling the timing curve with rpm and MAP. At lower power levels, disabling the leading ignition clearly has a = larger effect than disabling the trailing - as one would expect. At = somewhere around 18" MAP, (don't know right now what rpm that is, maybe = close to 4000) the effect is about equal when disabling either set. At = higher power levels, there is a larger effect of disabling the trailing = than the leading. That troubles me. I think the leading should always = have a greater effect. It makes me wonder about the timing; or if = something else is wrong.=20 I have in the past tried varying the timing 2 or 3 steps while at = power, but couldn't discern a change in rpm greater than the normal = variation in the readout. Tracy sent me the XL spreadsheet with the = timing curve data, but I haven't yet figured a safe way of checking it = with that prop spinning close by. Does your installation exhibit the same behavior? Is there some = explanation for this? What test should I perform? One thing that occurs to me is that Tracy measures MAP out before = the runners. I measure MAP at the manifold, downstream from intake = plenum and three short runners and the 3-barrel TWM throttle body. At = WOT my MAP is not atmospheric pressure - it is maybe 2-3" HG less. I = can't quite see how that is an issue; but maybe someone else with a TWM = TB setup with the MAP port downstream would know. Other than that I'm very pleased with the new mixture correction = table setup for the 20B. Much less tuning and seamless transistion = between tables and through the stage point. Probably the pulse clamping = and injector isolation diodes are part of that. -------------------------------------------------------------------------= --- No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.487 / Virus Database: 269.13.22/1013 - Release Date: = 17/09/2007 1:29 PM ------=_NextPart_000_000D_01C7FA1B.AA8F5690 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al, I did not catch what your ignition timing = you have set=20 when encountering this.  IF you set the ignition timing with = little/no=20 advance/retard then you are around 25 deg BTDC.
 
Here's some thoughts on what might be = happening(just a=20 SWAG).  At lower rpm generally require less ignition advance = because the=20 combustion has more time to get completed, therefore  the spark = does not=20 need to start as early (less advance).     However, as = RPM=20 increases the time for a the combustion event becomes less and less = which=20 means you normally would have your ignition advancing to=20 compensate.   I know you know this, but bear with=20 me.
 
IF you ignition was advancing to the point that = the=20 leading plug spark point was exceeding the optimum for those combustion=20 conditions (rpm, manifold pressure, ignition timing, etc), = then the=20 trailing spark which lags might start to become the optimum = spark in=20 relation to the optimum spark point.  If so then I would expect the = higher=20 the rpm the more influence the trailing spark might have.
 
So what would you check.
 
1.  I recall back a couple of years ago = there was=20 some discussion about the stock pulleys on certain model year 13Bs being = keyed=20 different (bolt hole pattern) on some year models such that the timing = point was=20 10 deg difference.  I don't suppose you have two pulleys laying = around that=20 you could compare the bolt hold pattern in the hub (match two of them up = with=20 the holes and check the timing marks?) and then check hub on you = engine.  A=20 very long shot, but  thought I would mention it.  Because in = the=20 unlikely event you would have a hub mismatch with your pulley then of = course,=20 your timing would be 10 degrees off.
 
2.  Unlikely as well, but I assume there is = no change=20 the coils (you have six?) could be sequenced/hooked up improperly.  = I don't=20 know what the effect would be if the leading coils were sparking the = trailing=20 plugs with the EC2.  I know the timing split between the leading = and=20 trailing is much less than in the automobile ignition timing - but I do = not=20 believe it is zero.  So the engine might well run, but might have = some=20 unexpected things happening.
 
3.  I have disabled my leading ignition = while flying=20 (it helps if you encounter a bad case of SAG) and I notice no = difference in=20 power although the EGT on both will increase about 150F from = 1600-1750F. =20 Do you notice any change in your EGT when you do this?
 
Well, that is about all of the wild theories I = can come up=20 with at the moment. 
 
ED
  
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Tuesday, September 18, = 2007 3:40=20 PM
Subject: [FlyRotary] Re: One = for the guys=20 that don't give up

The reason = Tracy gave for=20 the ECU not working was because of that set-up, as his Vacuum = pick -up=20 is at the Plenum - something to do with fluctuations within the = tube,=20 whereby the plenum was static or less successful to wild=20 fluctuations.

George ( down=20 under)

 

I have = accumulator=20 and orifice which smooths the MAP nicely.

 

Dave said:  Besides a = slight=20 difference in the mixture necessary between the 2 computers, both = locations=20 seem to work well.

 

Dave:  = Mine works=20 well also - except for the anomaly noted.  I don=92t know if you = mean that=20 yours specifically doesn=92t exhibit that = phenomenon?

 

Al, was = 35=B0 BTDC=20 Tracys suggested timing?

 

The = 35o=20 BTDC is the static setting specified in Tracy=92s = manual; line up=20 the 2-point trigger wheel with the reluctors at that = point.

 

Quite frankly, I haven't tried the coil = disable=20 feature at high rpm yet.  So, I don't have an answer to your = question.  Heck, I can't even get my auto-tune to=20 work. 

 

Mark; = well,=20 whenever you get that far, give it a shot and see what you get. Good = luck with=20 the auto-tune.

 

  Does anyone else experience these = symptoms?=20   That=92s = the=20 question.

 

Thanks,=20 guys,

 

Al

 

 

 

 

 

OK; = Mark; (or=20 anybody).  Since we both have 20Bs, and both use the EC2 = controller,=20 maybe you have a clue for this one. I=92ve brought this up here = before, but no=20 solution.

I=20 have all the latest updates on the EC2, and I have double checked = the static=20 timing set at 35o BTDC.  From that point on the EC2 = is=20 handling the timing curve with rpm and MAP.

At=20 lower power levels, disabling the leading ignition clearly has a = larger=20 effect than disabling the trailing =96 as one would expect.  At = somewhere=20 around 18=94 MAP, (don=92t know right now what rpm that is, maybe = close to 4000)=20 the effect is about equal when disabling either set.  At higher = power=20 levels, there is a larger effect of disabling the trailing than the=20 leading.  That troubles me.  I think the leading should = always=20 have a greater effect.  It makes me wonder about the timing; or = if=20 something else is wrong.

I=20 have in the past tried varying the timing 2 or 3 steps while at = power, but=20 couldn=92t discern a change in rpm greater than the normal variation = in the=20 readout.  Tracy sent = me the XL=20 spreadsheet with the timing curve data, but I haven=92t yet figured = a safe way=20 of checking it with that prop spinning close by.

Does=20 your installation exhibit the same behavior?  Is there some = explanation=20 for this?  What test should I perform?

One=20 thing that occurs to me is that Tracy = measures MAP out=20 before the runners.  I measure MAP at the manifold, downstream = from=20 intake plenum and three short runners and the 3-barrel TWM throttle=20 body.  At WOT my MAP is not atmospheric pressure =96 it is = maybe 2-3=94 HG=20 less.  I can=92t quite see how that is an issue; but maybe = someone else=20 with a TWM TB setup with the MAP port downstream would=20 know.

 

Other = than that=20 I=92m very pleased with the new mixture correction table setup for = the=20 20B.  Much less tuning and seamless transistion between tables = and=20 through the stage point.  Probably the pulse clamping and = injector=20 isolation diodes are part of that.

No virus found in this = incoming=20 message.
Checked by AVG Free Edition.
Version: 7.5.487 / = Virus=20 Database: 269.13.22/1013 - Release Date: 17/09/2007 = 1:29=20 PM

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