Tuned pipe or muffler with large 2-Strokes?

[Adam Glatt]

I have never heard any 2 stroke user complain about spool up time, and I have never felt it was a disadvantage.  I don't think there is an issue with it on a properly set up tuned pipe.  The only time spool up time on a 2 stroke becomes slow, that I have experienced, is if I have a poorly tuned pipe and run at half throttle.  It will load up at half throttle and take around 3 seconds to get to full throttle.  Get the pipe length right, though, and this disappears.

The biggest advantage a 4 stroke has above a 2 stroke is in downline braking, from what I have seen.  They don't seem to hold their idle RPM like a 4 stroke does, so the downlines are a little faster.
  ----- Original Message ----- 
  From: Keith Black 
  To: discussion at nsrca.org 
  Sent: September 21, 2002 1:50 AM
  Subject: Tuned pipe or muffler with large 2-Strokes?


  I'd like to hear some feedback on running tuned pipes vs. mufflers on the large 2-stroke engines such as the OS 1.40RX, Webra 1.45 and Bully 1.45.

  What I've understood is that these large engines have plenty of power running just a muffler without a tuned pipe, and by not running a tuned pipe the throttle response should be smoother and not so "peaky". I'd think the smoother throttle response would make flying pattern much easier. Certainly one of the benefits of 4-strokes is the instant throttle response with no spin-up time. It seems as though using a pipe would just aggravate the spin-up issue with 2-strokes.

  However, in reading some of the messages lately I see that people are still running tuned pipes on these engines. For example, under the "Webra Bragging" thread Matt indicated that he is running a Webra 1.45 with an OS/Hatori tuned pipe and it flies very well.

  I'd really appreciate hearing everyone's experiences relating to this issue.

  Thanks,
  Keith Black




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