Webra 1.45 tuning length?

[David Lockhart]

Grieve. It has a constant outside diameter - save a short neck and the stinger.

Dave

  ----- Original Message ----- 
  From: Rcmaster199 at aol.com 
  To: discussion at nsrca.org 
  Sent: Friday, January 07, 2005 1:31 AM
  Subject: Re: Webra 1.45 tuning length?


  Dave, what pipe is the 1100/260? Whose mfg?

  MattK

  In a message dated 1/7/2005 12:29:01 AM Eastern Standard Time, DaveL322 at comcast.net writes:
    Ryan,

    The Asano setup is designed for the OS140 which has different port timing than the 145 - the stock setup is about 24" (610 mm) exhaust flange to tuning baffle.

    The recommended tune length from Webra for the 145 using the tuned muffler (Horizon part # 1100/260, I believe also sold by Piedmont) is 780mm (30.75"), from the exhaust flange to the flat end of the pipe before the exhaust stinger.  800m for the 160 - which is interesting because the 160 is a lower timed engine which typically will utilize a shorter tune length.  I believe Webra is specifying these tune lengths for approx 8100 RPM.

    I am running the 160s and find that the 1100/260 at 31" ( 787 mm) to the flat end (24" to the tuning baffle) and the Asano at 23.785" run similarly at about 7700 RPM.

    More RPM = shorter pipe.  If the pipe is too short, the main needle will be sensitive and the midrange will be less linear.

    Less RPM = longer pipe.  If the pipe is too long, the boost of the pipe will be limited, and the engine will be very "friendly".

    Anywhere between 25-27" should work, best length will depend on prop and flying style.

    Regards,

    Dave

    ----- Original Message ----- 
      From: Rcmaster199 at aol.com 
      To: discussion at nsrca.org 
      Sent: Thursday, January 06, 2005 10:48 PM
      Subject: Re: Webra 1.45 tuning length?


      I am still flying the 145 blackhead  too. I use the Hatori/os140  pipe with the macs header. The first reflector is set at 24inches from the plug, straight line. I don't know how the Asano is setup inside so use the first reflector distance as a good place to start.

      MattK

      In a message dated 1/6/2005 10:06:30 PM Eastern Standard Time, Acroman300 at aol.com writes:
        Hello guys,

        I would like to know the tuning lengths that you all are running with the Webra 1.45. I have the blackhead version and am running an Asano pipe. I was running the flex header combo with it, but it broke and really didn't seem that it was tuned as well as it could be, as it was a pretuned system. Any input is greatly appreciated.

        Ryan Smith

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