X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.238] verified) by logan.com (CommuniGate Pro SMTP 5.2.5) with ESMTP id 3043093 for flyrotary@lancaironline.net; Sat, 26 Jul 2008 08:42:56 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.238; envelope-from=rwstracy@gmail.com Received: by rv-out-0506.google.com with SMTP id f6so3263867rvb.7 for ; Sat, 26 Jul 2008 05:42:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:sender :to:subject:in-reply-to:mime-version:content-type:references :x-google-sender-auth; bh=rZccofq9BMUBFVU/+zOrQNViv0qF/yz5u35UYdac0Cs=; b=mSes7RYEmLupttdKaHGvqMfHckVazO38eKWaRgFCDRLhFmLoF+5VhelwULvQBM8Wr5 vfb0/7SZsqi+2QItA0jk9ZDd58OJ55gg0KgeDkzYISek9VC5DyICCjyw/kBREdLSDI5y sb4ce/lokF26w94ZUwxpqLe57LBmXT4gfCyto= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:in-reply-to:mime-version :content-type:references:x-google-sender-auth; b=fI2+msUW0wxowvh03rux8JW4yykiB4ctGOiINAZduUuuiVVOPlx+B2s54fdK+UY77h fbqrtUbe1KezcxNMeCdTpAVmVUCTX7VCb+Nx0/zwe9603oklgwG63qXgTvG96OX4JaUt SCSI2qHXkg+6fP57iyhod6f0XaeKGULCmF80s= Received: by 10.141.29.8 with SMTP id g8mr1404453rvj.62.1217076127389; Sat, 26 Jul 2008 05:42:07 -0700 (PDT) Received: by 10.141.82.18 with HTTP; Sat, 26 Jul 2008 05:42:07 -0700 (PDT) Message-ID: <1b4b137c0807260542w7f257496q86caaffd120b3855@mail.gmail.com> Date: Sat, 26 Jul 2008 08:42:07 -0400 From: "Tracy Crook" Sender: rwstracy@gmail.com To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] 13B--- N/A vs. Turbo engine buildup? In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_3663_10559242.1217076127367" References: X-Google-Sender-Auth: 6b79d4be81ad49cf ------=_Part_3663_10559242.1217076127367 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Note that the difference is at the torque peak, not the HP peak which is what we are concerned with. At the HP peak (6000 - 7000 RPM) the difference made by compression ratio in HP is close to zero. Note also that the BSFC is slightly better with the higher CR. That was the main reason I went with the higher CR rotors. Even this is not a big deal though. I doubt that the money spent on new NA rotors would be recouped in many years of fuel costs. But use'em if you got'em. Tracy On Fri, Jul 25, 2008 at 11:03 PM, cbeazley wrote: > Paul & Don Vermillion; > > Q: HP difference between NA & Turbo? > The HP difference between NA and turbo rotors is 3-5% approaching the > torque peak. > See the bible, 81 edition (near the bottom of the web page), p.49. > http://www.wankel.net/~krwright/cars/rx7/manuals.html > Here is a chart of rotor information: > http: > //www.mazdatrix.com/faq/rotorwgt.htm > This ignores the intake port timing and size differences of the housings. > http:// > www.yawpower.com/dectech.html > > All intake/exhaust ports can be ported for more power at the top end. Mild > street port and extended street port are good options. Peripheral port > (PPorts) are a more involved option. > Here are a few web sites with pics of various port types - don't believe > everything that is written - particularly idle RPMs. > http://www.turborx7.com/portingpictures.htm > http://www.mazdarotary.net/porting.htm > > There is lots of information on these sites: > http://www.rx7club.com > http://www.nopistons.com > > One of the nice things about the 13B is that most parts can be mixed and > matched. Turbo and NA have different size oil pumps. > You should not mix NA and turbo rotors. Counterweights should match the > generation of the rotors. Looks for threads on balancing if you need to > change a rotor. > > Later model generations of engines have incremental improvements. > There are differences between the generations of housings: > http://www.rotaryresurrection.com/2ndgen/tech_housing_differs.html > > NA housings have an exhaust port noise splitter/diffuser in the insert. The > insert can be replaced or the splitter ground out (with some difficulty). > (see bottom left of photo). As has been mentioned, the NA exhaust splitter > is worth 7-8db of noise reduction for an unknown reduction in HP. > There are also some minor passage differences between the generations... > Series 5 and later housings have a knock sensor above the top trailing > spark plug (top right in photo) > > Cheers > Cary > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > ------=_Part_3663_10559242.1217076127367 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline
Note that the difference is at the torque peak, not the HP peak which is what we are concerned with.  At the HP peak (6000 - 7000 RPM) the difference made by compression ratio in HP is close to zero.
 
Note also that the BSFC is slightly better with the higher CR.  That was the main reason I went with the higher CR rotors.  Even this is not a big deal though.  I doubt that the money spent on new NA rotors would be recouped in many years of fuel costs.  But use'em if you got'em.
 
Tracy

On Fri, Jul 25, 2008 at 11:03 PM, cbeazley <cbeazley@innovista.net> wrote:
Paul & Don Vermillion;

Q: HP difference between NA & Turbo?
The HP difference between NA and turbo rotors is 3-5% approaching the torque peak.
See the bible, 81 edition (near the bottom of the web page), p.49.
    http://www.wankel.net/~krwright/cars/rx7/manuals.html
Here is a chart of rotor information:
        http://www.mazdatrix.com/faq/rotorwgt.htm
This ignores the intake port timing and size differences of the housings.
    http://www.yawpower.com/dectech.html

All intake/exhaust ports can be ported for more power at the top end.  Mild street port and extended street port are good options.  Peripheral port (PPorts) are a more involved option.
Here are a few web sites with pics of various port types - don't believe everything that is written - particularly idle RPMs.
    http://www.turborx7.com/portingpictures.htm
    http://www.mazdarotary.net/porting.htm

There is lots of information on these sites:
    http://www.rx7club.com
    http://www.nopistons.com

One of the nice things about the 13B is that most parts can be mixed and matched.  Turbo and NA have different size oil pumps.
You should not mix NA and turbo rotors.  Counterweights should match the generation of the rotors.  Looks for threads on balancing if you need to change a rotor.

Later model generations of engines have incremental improvements.
There are differences between the generations of housings:
    http://www.rotaryresurrection.com/2ndgen/tech_housing_differs.html

NA housings have an exhaust port noise splitter/diffuser in the insert. The insert can be replaced or the splitter ground out (with some difficulty).  (see bottom left of photo).  As has been mentioned, the NA exhaust splitter is worth 7-8db of noise reduction for an unknown reduction in HP.
There are also some minor passage differences between the generations...
Series 5 and later housings have a knock sensor above the top trailing spark plug (top right in photo)

Cheers
Cary

--
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html


------=_Part_3663_10559242.1217076127367--