Mailing List lml@lancaironline.net Message #18368
From: Jeffrey Peterson <jbp@fire.phys.cmu.edu>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: LNC2 Tuned exhaust.
Date: Sun, 06 Apr 2003 21:54:15 -0400
To: <lml>

Chuck,

The workmanship on the tuned exhaust looks exceptional.

NICE!

Isn't the standard length about 65 inches from cylinder to the output?  
Your system is shorter than that. In particular your headers are much
shorter than other tuned exhausts.  any special trick at play? I'd really
like to use a tuned exhaust on my Lyc. IO360 but its tough to fit in 72"  
of pipe. I like your system, but wonder how you can get away with the
short headers.

For reference I attach a photo of the powerflow system for the 172.
Long headers, then a collector about the size of your collector/cone.

Did you dyno the system with your tuned exhaust compared to some standard?

CAFE did tests on tuned exhausts a few years back, see
http://members.eaa.org/home/flight_reports/epg1.html
(also epg2, epg3, epg4) unfortunately the plots are not on the web
page and they did not use a dyno, instead they tested for rpm at
full throttle. their main result: a 25 inch collector is optimum.
headers in the range 36 to 42" worked well.  you have the 25 inch
collector, but much shorter headers.

just curious.   again...nice work.

-Jeff Peterson
LNC2 N273CK...still building...leak checking left extended tank

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