X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-d03.mx.aol.com ([205.188.157.35] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2270535 for flyrotary@lancaironline.net; Sat, 18 Aug 2007 08:37:56 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.157.35; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-d03.mx.aol.com (mail_out_v38_r9.2.) id q.d4c.a20475e (14457) for ; Sat, 18 Aug 2007 08:37:14 -0400 (EDT) From: Lehanover@aol.com Message-ID: Date: Sat, 18 Aug 2007 08:37:13 EDT Subject: Re: [FlyRotary] Re: Air/fuel flow To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1187440633" X-Mailer: 9.0 Security Edition for Windows sub 5374 X-Spam-Flag: NO -------------------------------1187440633 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/18/2007 3:13:31 A.M. Eastern Daylight Time, lendich@optusnet.com.au writes: Lynn, The question was on inlet velocity for a Mazda rotary at 7,500 rpm - if you happened to have some info on that. Everyday cars have 450' per sec and race cars 125' per second,( suggested on a carb site) Ed's calculations used 176' per second which indicated a bigger inlet diameter. I was thinking about 300 to 350' per second would more like it, but I have no real hard data! Well then let me speculate. The engines have two RPM where they wander above 100% VE. These are too low to help us much but the car designers use this and stretch it out a bit looking at the pipe organ intakes. Just off idle and about 2,000 RPM. This confuses the idle and transition circuits in the Weber and you get a nice Rumppp...Rumppp...Rumppp. Breathing is very good compared to a piston engine, and runner diameter is small for any HP output. The stock intake manifold gasket in my engines (Daryl Drummond) is barely enlarged at all. The new engine may have more than two such RPM. Porting extends the intake open time and makes for a more turbine like flow. Even a street port can nearly double the stock HP, and that would require nearly double the stock airflow. Down low the race or even street ported engine has little advantage over the stock engine. For any RPM the air flow determines the HP output, so where (RPM) you are interested in output there will need to be dramatically improved airflow. So generally, the displacement times the RPM minus some percentage for inlet restriction based on TP size or carb choke size and or runner length and diameter will be the stock situation and one CFM value. And in a modified intake system with longer runners of slightly more diameter which will favor the same RPM as the stock example engine will have very much more power than a stock engine at the same RPM, indicating a much higher than stock (CFM) air flow. Maybe not over 100% VE but much closer to that number than the stock engine. There is no cheating possible here. So if your example engine is compared to any other engine with more power at the same RPM. The higher power output requires very much more airflow, not less. Something is amiss Watson.........I can feel it! Lynn E. Hanover ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour -------------------------------1187440633 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 8/18/2007 3:13:31 A.M. Eastern Daylight Time,=20 lendich@optusnet.com.au writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
Lynn,
The question was on inlet velocity for a Mazda rotary at 7,500 rpm -=20= if=20 you happened to have some info on that.
 
Everyday cars have 450' per sec and race cars 125' per second,( sugge= sted=20 on a carb site) Ed's calculations used 176' per second which=20 indicated a bigger inlet diameter. I was thinking about 300 to 350' per se= cond=20 would more like it, but I have no real hard=20 data!
Well then let me speculate.
 
The engines have two RPM where they wander above 100% VE. These are too= low=20 to help us much but the car designers use this and stretch it out a bit= =20 looking at the pipe organ intakes.
 
Just off idle and about 2,000 RPM. This confuses the idle and transitio= n=20 circuits in the Weber and you get a nice Rumppp...Rumppp...Rumppp.=20 Breathing is very good compared to a piston engine, and runner diameter is s= mall=20 for any HP output. The stock intake manifold gasket in my engines (Daryl=20 Drummond) is barely enlarged at all. The new engine may have more than two s= uch=20 RPM.
 
Porting extends the intake open time and makes for a more turbine like=20 flow. Even a street port can nearly double the stock HP, and that would requ= ire=20 nearly double the stock airflow. Down low the race or even street ported eng= ine=20 has little advantage over the stock engine. For any RPM the air flow determi= nes=20 the HP output, so where (RPM) you are interested in output there will need t= o be=20 dramatically improved airflow. 
 
So generally, the displacement times the RPM minus some percentage for=20 inlet restriction based on TP size or carb choke size and or runner length a= nd=20 diameter will be the stock situation and one CFM value.
 
And in a modified intake system with longer runners of slightly more=20 diameter which will favor the same RPM as the stock example engine will= =20 have very much more power than a stock engine at the same RPM, indicating a=20= much=20 higher than stock (CFM) air flow. Maybe not over 100% VE but much closer to=20= that=20 number than the stock engine.
 
There is no cheating possible here. So if your example engine is compar= ed=20 to any other engine with more power at the same RPM. The higher power output= =20 requires very much more airflow, not less.
 
Something is amiss Watson.........I can feel it!
 
Lynn E. Hanover   



Get a sneak peek of the all-new AOL.com.
-------------------------------1187440633--