How to know which pipe to use.

[Dean Pappas]

Hello Gabriel,
Any of the YSes benefit from a free-flowing exhaust.
This is true of both the running characteristics and the noise level.
In general, the "stock" Hattori pipe is the smallest thing that should be used.
Greater expansion volume improves horsepower, and reduces engine temperature.
Two-cycle 120~140 pipes work well, and soften the raspy exhaust note.
Even a two-stroke 60-sized pipe is preferable. 
I last used an Hattori #900 (the stock O.S. 140 RX pipe)pipe at the end of a
7/16" inside diameter aluminum extension pipe from the header.
Teflon couplers were used. It is best to have approximately 12" of header
length before the expanding cone begins. Unfortunately, short, small exhausts
are not as good as a full-size system.
Regards,
	Dean P.


-----Original Message-----
From: Gabriel Gonzalez [mailto:gabrielg74 at jz.cablemas.com]
Sent: Wednesday, October 08, 2003 1:28 PM
To: discussion at nsrca.org
Subject: How to know which pipe to use.



  I got a 7.5cc Macs quiet pipe for my 140FZ, but I'm not sure if it's the
  right thing to use.

  How can it be determined what would be a good pipe to use with a 4c
engine?

  7.5cc seem awfully small, but in an earlier post I saw someone using a
 3.5cc
  pipe!!!! Was this a typo?

  I don't want to ruin my engine or my plane, and thought to ask before
 trying
  it.

  Thank you,

  Gabriel González


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