Return-Path: <13brv3@bellsouth.net> Received: from imf20aec.mail.bellsouth.net ([205.152.59.68] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2576995 for flyrotary@lancaironline.net; Fri, 12 Sep 2003 09:55:39 -0400 Received: from rad ([68.212.12.251]) by imf20aec.mail.bellsouth.net (InterMail vM.5.01.05.27 201-253-122-126-127-20021220) with ESMTP id <20030912135442.QKWR1780.imf20aec.mail.bellsouth.net@rad> for ; Fri, 12 Sep 2003 09:54:42 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: turbo wastegate requirements Date: Fri, 12 Sep 2003 08:54:42 -0500 Message-ID: <00ee01c37935$6aacc140$0201a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00EF_01C3790B.81D6B940" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_00EF_01C3790B.81D6B940 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable On a 60 F day, the OAT at 16k ft is about 22 F; on an 80 F day, the OAT = is maybe 42 F. These temps would tend to reduce intercool requirements and cool the turbine which I assume (key word here) is the reason for = limiting boost to 8 psi. =20 =20 8 psi is a rough figure that I came up with after searching through some RX-7 forum info. This seems like a reasonable value that folks are = running on the street. Since that's already more than I need, I didn't look = further to see why they don't go higher. It may not be a turbo limit, so much = as a limit to the engine computer, or fuel injectors. For example, on the = 3rd gen engine, you can run aftermarket exhaust and intake with the stock 10 = psi boost level using the stock computer. If you want more boost, you have = to install an aftermarket computer. This will get you to about 13 psi, = then you run out of fuel injector capacity. Next you run out of fuel pump capacity, etc. The stock twin turbos can be run to about 17 psi, but = this is way above their efficient range, which means they're heating the air = much more than a larger turbo would do at that same pressure. In that = respect, running higher than normal boost for a given turbo will increase the = need for intercooling. =20 =20 Rusty ------=_NextPart_000_00EF_01C3790B.81D6B940 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
On a 60 F day, the OAT at = 16k ft is=20 about 22 F; on an 80 F day, the OAT is maybe 42 F.  These temps = would tend=20 to reduce intercool requirements and cool the turbine which I assume = (key word=20 here) is the reason for limiting boost to 8 psi.   
 
8 psi is a rough figure that I came up with after = searching=20 through some RX-7 forum info.  This seems like a reasonable value = that=20 folks are running on the street.  Since that's already more than I = need, I=20 didn't look further to see why they don't go higher.  It may = not be a=20 turbo limit, so much as a limit to the engine computer, or fuel = injectors. =20 For example, on the 3rd gen engine, you can run aftermarket exhaust = and=20 intake with the stock 10 psi boost level using the stock computer.  = If you=20 want more boost, you have to install an aftermarket computer.  This = will=20 get you to about 13 psi, then you run out of fuel injector=20 capacity.  Next you run out of fuel pump capacity,=20 etc.   The stock twin turbos can be run to about 17 psi, = but this=20 is way above their efficient range, which means they're heating the = air=20 much more than a larger turbo would do at that same pressure.  = In that=20 respect, running higher than normal boost for a given turbo will = increase=20 the need for=20 intercooling.    
 
Rusty
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