X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m27.mx.aol.com ([64.12.137.8] verified) by logan.com (CommuniGate Pro SMTP 5.0.3) with ESMTP id 873279 for flyrotary@lancaironline.net; Mon, 12 Dec 2005 23:10:34 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.8; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m27.mx.aol.com (mail_out_v38_r6.3.) id q.1ee.4888bcdb (58808) for ; Mon, 12 Dec 2005 23:09:43 -0500 (EST) From: Lehanover@aol.com Message-ID: <1ee.4888bcdb.30cfa387@aol.com> Date: Mon, 12 Dec 2005 23:09:43 EST Subject: Re: [FlyRotary] Pport advice from the master To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1134446983" X-Mailer: 9.0 SE for Windows sub 5022 X-Spam-Flag: NO -------------------------------1134446983 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 12/12/2005 9:52:45 PM Eastern Standard Time, montyr2157@alltel.net writes: Who else but Lynn, Well, I just bought a 89-91 NA automatic motor. The plan is to Pport it. Basically leave the exhaust alone. Leave the splitters or not? The archives are a bit inconclusive here. In one post Lynn says to keep the splitters. In another he says the Pport is very sensitive to exhaust back pressure. All rotaries are sensitive to exhaust tuning, just exactly like a 2 cycle dirt bike engine. They are 4 stroke cycle engines but tune like 2 cycles. I would leave the splitters installed. I would add a bit of a radius to the opening line, and a slight radius all around the port, and then polish it all, just to keep any chrome flaking from involving the apex seal. The factory racing Pports have very small exhaust ports. I think you will loose more power trying to muffle the engine without the splitters than leaving them in will cost. By far, the most important feature of the system, is that the primary pipes should be as close to the same length as is possible. Both pipes at the same angle to the centerline of the collector. Muffler design is still not established, but there are some promising designs flying now. I have some turbo housings I can take the insert out of and put into the NA housings if need be. Other info I have says the exhaust should be ported to Close 55 deg ATDC vs 48 ATDC for stock while leaving the exhaust opening alone. Leave exhaust timing close to stock. That 6,000 RPM is nothing, hardley running. Intake timing: IO 80 deg BTDC IC 60 deg ABDC 13 in intake length? 31 in length header primaries 1 7/8-2 in dia Collector lengths as multipals of 12 or 13 inches should work fine. Even just 13" would work. And save a lot of space. The shorter the system the more accuratley it must be built. I saw a National champion winning Pport 12A with about 10" primaries. But that is good up to 10,000 RPM. The longer setup would have a slight advantage in torque at lower RPM. 3 in collector into muffler 2 in dia after muffler. For 6,000 RPM cruise I would go at least 2 1/2" tail pipe. 7500 max power 5500-6500 cruise power running LOP. 2.17 drive and a 68 in prop. I would go with the 2.78 reduction. Better choice of props, (right handed) and the engine has so little torque that it shows much better with more revs. My 12A has 139 foot pounds at 6,500 RPM or 173 HP. But at 7,500 RPM it has 152.5 foot pounds or, 218 HP. Plus the just talked about "P" factor will be under the correct rudder pedal. This allows for a longer (more efficient) prop. Start with as long as you dare and work back as required. I would want the cruise to be just over 6,000. Speed-fast hopefully. If it sounds like this I won't be upset: I would be. Come to the track with me next year, and you better wear some Depends the first day. When my car goes by at 9,600 and tickles the rev limiter. It makes your nose run. And mine is not the best sounding rotary by a long shot. We are limited to 103 dB. Years back, it was just too painful, so we ran a muffler when none was required. More like 110 dB in the car. And not a good sound at all. Just a nasty racket. Leave the splitters in. Who says they won't Idle? That is music to my ears!! Sewing machine be damned! A proper sound should cause spontaneous incontinence amongst the granolas. The Bridgeport engines are much worse at idle (2,000 RPM) than Pported engines, (1,200 RPM) just because there is less intake open time, and far less overlap. Another reason for the 2:78 reduction, you can tolerate a higher idle speed without dragging the brakes all of the time. Run an MSD, at least on the leading plugs. Should make one hell of an airplane engine. Lynn E. Hanover -------------------------------1134446983 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 12/12/2005 9:52:45 PM Eastern Standard Time,=20 montyr2157@alltel.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
Who else but Lynn,
 
Well, I just bought a 89-91 NA automatic=20= motor.=20 The plan is to Pport it.
 
Basically leave the exhaust alone. Leave=20= the=20 splitters or not? The archives are a bit inconclusive here. In one post Ly= nn=20 says to keep the splitters. In another he says the Pport is very sensitive= to=20 exhaust back pressure.
 
All rotaries are sensitive to exhaust tuning, just exactly like a 2 cyc= le=20 dirt bike engine. They are 4 stroke cycle engines but tune like 2 cycles. I=20 would leave the splitters installed. I would add a bit of a radius to the=20 opening line, and a slight radius all around the port, and then polish it=20 all,  just to keep any chrome flaking from involving the apex= =20 seal.
 
The factory racing Pports have very small exhaust ports. I think you wi= ll=20 loose more power trying to muffle the engine without the splitters than leav= ing=20 them in will cost. By far, the most important feature of the system, is that= the=20 primary pipes should be as close to the same length as is possible. Both pip= es=20 at the same angle to the centerline of the collector.
Muffler design is still not established, but there are some promising=20 designs flying now.
 
 
 
I have some turbo housings I can take= the=20 insert out of and put into the NA housings if need be. 
 
Other info I have says the exhaust should= be=20 ported to Close 55 deg ATDC vs 48 ATDC for stock while leaving the exhaust= =20 opening alone.
 
Leave exhaust timing close to stock. That 6,000 RPM is nothing, hardley= =20 running.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
 
Intake timing:
 
IO 80 deg BTDC
IC 60 deg ABDC
 
13 in intake length?
 
31 in length header primaries 1 7/8-2 in=20 dia
 
Collector lengths as multipals of 12 or 13 inches should work fine. Eve= n=20 just 13" would work.
And save a lot of space. The shorter the system the more accuratley it=20= must=20 be built. I saw a National champion winning Pport 12A with about 10" primari= es.=20 But that is good up to 10,000 RPM. The longer setup would have a slight=20 advantage in torque at lower RPM.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
 
3 in collector into muffler
 
2 in dia after=20 muffler.
 
For 6,000 RPM cruise I would go at least 2 1/2" tail pipe.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
 
7500 max power
 
5500-6500 cruise power running LOP.
 
2.17 drive and a 68 in=20 prop.
I would go with the 2.78 reduction. Better choice of props, (right hand= ed)=20 and the engine has so little torque that it shows much better with more revs= . My=20 12A has 139 foot pounds at 6,500 RPM or 173 HP. But at 7,500 RPM it has 152.= 5=20 foot pounds or, 218 HP.
 
Plus the just talked about "P" factor will be under the correct rudder=20 pedal.
This allows for a longer (more efficient) prop. Start with as long as y= ou=20 dare and work back as required. I would want the cruise to be just over 6,00= 0.=20
 
Speed-fast hopefully.
 
If it sounds like this I won't be=20 upset:
 
I would be. Come to the track with me next year, and you better wear so= me=20 Depends the first day. When my car goes by at 9,600 and tickles the rev limi= ter.=20 It makes your nose run. And mine is not the best sounding rotary by a long s= hot.=20 We are limited to 103 dB. Years back, it was just too painful, so we ran a=20 muffler when none was required. More like 110 dB in the car. And not a good=20 sound at all. Just a nasty racket. Leave the splitters in.
 
Who says they won't Idle? That is music t= o my=20 ears!! Sewing machine be damned! A proper sound should cause=20 spontaneous incontinence amongst the granolas.
 
The Bridgeport engines are much worse at idle (2,000 RPM) than Pported=20 engines, (1,200 RPM) just because there is less intake open time, and far le= ss=20 overlap. Another reason for the 2:78 reduction, you can tolerate a higher id= le=20 speed without dragging the brakes all of the time.
 
Run an MSD, at least on the leading plugs. Should make one hell of an=20 airplane engine.
 
Lynn E. Hanover 
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
 
 
-------------------------------1134446983--