Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.6) with ESMTP id 2702772 for flyrotary@lancaironline.net; Thu, 30 Oct 2003 07:37:27 -0500 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id h9UCaqQU014248 for ; Thu, 30 Oct 2003 07:36:53 -0500 (EST) Message-ID: <003501c39ee1$f92b4aa0$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Intake manifold Date: Thu, 30 Oct 2003 07:33:07 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0032_01C39EB8.0FC75A80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0032_01C39EB8.0FC75A80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable =20 Opps, should read: On the 1988 NA the secondary port runners should = be about 4 inches shorter than the primaries. Finn Lassen wrote: Jim Sower wrote: <... a simple way to cut down on the amount of fuel/air mixture = during idle ... yet have plenty of reserves at redline rpm ...>=20 So why do I need primarys and secondarys with different lengths = that screw up DIE and generally make life more difficult?=20 There must be more to this than meets the eye ... Jim S. According to the graphs Ed distributed after the presentation, on = the 1990 Turbo and street ported 1991 Turbo II their primary and = secondary runners can be identical lengths. On the 1988 NA the secondary port runners should be about 4 inches = longer than the primaries. This presumably is for a non-street ported = engine. Any porting will dramatically alter the required lengths. Come on, Ed. Help me out here! Finn Hi Jim, Finn Good question and answer. As I hope I made clear, the DIE effect is = an adjunct to an already good intake system. There are several other = factors than DIE that carry more weight (than DIE) in producing power. = One appears to be the velocity of the air/fuel mixture in your pipes. = Too slow is apparently not good and that depends on (among other things) = on the diameters of the pipes. What you want/need for an automobile installation is different than = for an aircraft. An example is with the torque, auto engines are = generally tuned to produce gobs of torque at relatively low rpms to give = the vehicle that breath taking 0-60MPH acceleration. We of course want = the torque and power at different (generally higher) rpms. Therefore we = have the different lenghts and diameters of the auto engine manifold = all for good and valid reasons. I do not have any data one way or the other about what changing the = intake system and port timing does to the basic breathing of the rotary. = Paw Yaw's web site probably has as good as I have seen on that aspect. = I believe (but have no data to support the belief) that if you want = the DIE effect at only one rpm, then given all else is equal (which it = seldom is) then it may make sense to port an engine to give the same = timing on both primary and secondary. I think this would be hard (and = not necessarily good) to do on the 6 port as there is a wide difference = between say the secondary and aux timing. I think it is easier to get = the two ports on a turbo block equal in timing without major challenges. I will be merging my primary and secondary runners shortly after = they exit the engine block on my next manifold. My ports are already = equal in timing. So hopefully with in the next month or two, I will = have this new intake fabricated and can provide some data on the = results. Hope this addresses your question. Best Regard Ed Anderson ------=_NextPart_000_0032_01C39EB8.0FC75A80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
Opps,=20 should read:  On the 1988 NA the secondary port runners should be = about 4=20 inches shorter than the primaries.

Finn Lassen = wrote:
Jim Sower = wrote:
<... a = simple=20 way to cut down on the amount of fuel/air mixture during idle ... = yet have=20 plenty of reserves at redline rpm ...>
So why do I need primarys and secondarys with different = lengths=20 that screw up DIE and generally make life more difficult? =
There=20 must be more to this than meets the eye ... Jim = S.
According to the graphs Ed distributed after the presentation, = on the=20 1990 Turbo and street ported 1991 Turbo II  their primary and = secondary=20 runners can be identical lengths.

On the 1988 NA the = secondary port=20 runners should be about 4 inches longer than the primaries. This = presumably=20 is for a non-street ported engine. Any porting will dramatically = alter the=20 required lengths.

Come on, Ed. Help me out = here!

Finn
 
Hi Jim, Finn
 
Good question and answer.  As = I hope I=20 made clear, the DIE effect is an adjunct to an already good intake=20 system.  There are several other factors than DIE that carry = more=20 weight (than DIE) in producing power.  One appears to be the = velocity=20 of the air/fuel mixture in your pipes.  Too slow is apparently = not good=20 and that depends on (among other things) on the diameters of the=20 pipes.
 
What you want/need for an = automobile=20 installation is different than for an aircraft.  An example is = with the=20 torque, auto engines are generally tuned to produce gobs of torque = at=20 relatively low rpms to give the vehicle that breath taking 0-60MPH=20 acceleration.  We of course want the torque and power at = different=20 (generally higher) rpms.  Therefore we have  the=20 different  lenghts and diameters of the auto engine manifold = all for=20 good and valid reasons.
 
I do not have any data one way or = the other=20 about what changing the intake system and port timing does to the = basic=20 breathing of the rotary.  Paw Yaw's web site probably has as = good as I=20 have seen on that aspect. 
 
I believe (but have no data to = support the=20 belief) that if you want the DIE effect at only one rpm, then given = all else=20 is equal (which it seldom is) then it may make sense to port an = engine to=20 give the same timing on both primary and secondary.  I think = this would=20 be hard (and not necessarily good) to do on the 6 port as there is a = wide=20 difference between say the secondary and aux timing.  I think = it is=20 easier to get the two ports on a turbo block equal in timing without = major=20 challenges.
 
I will be merging my primary and = secondary=20 runners shortly after they exit the engine block on my next = manifold. =20 My ports are already equal in timing.  So hopefully with in the = next=20 month or two, I will have this new intake fabricated and can provide = some=20 data on the results.
 
Hope this addresses your = question.
 
Best Regard
 
Ed Anderson
 
 
 
 
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