question regarding header & tuned pipe

[wgalligan]

Bill,

This may be optimal for top end but where you really want optimal performance on a 2 stroke is in the midrange and backing up a little helps in that range... so I have been told... and it works on my engine...  so THERE.    Heh! heh!....

 Wayne,
> 
> Good suggestion for tuning the pipe, however, there is a school of thought
> that suggests going a little shorter (or past) optimal rpm on the test stand
> when shortening the pipe, because the engine will unload in the air thus
> increasing rpm.  The result is that you're tuning to a higher rpm in the air
> than on the ground, and higher rpm means shorter pipe.  You can't really
> confirm this unless you find a way to tach the engine in the air.  Just a
> thought - my $0.02.
> 
> Bill
> 
> ----------
> >From: wgalligan <wgalligan at cnbcom.net>
> >To: discussion at nsrca.org <discussion at nsrca.org>
> >Subject: Re: question regarding header & tuned pipe
> >Date: Tue, Mar 25, 2003, 7:40 AM
> >
> 
> > I have a header (Karl Mueller type, one of the best custom mades I have
> > seen) that has a smaller diameter then the pipe itself and it does not seem
> > to effect the tuning.  If you can set up your engine on a test stand then
> > move the pipe to a long setup to begin with.  Then move the pipe in a .25
> > inch at a time and check rpm's.  There should be an increase in rpm each
> > move of the pipe.  Keep moving it till the rpm's max out then back the pipe
> > out to the previous position.  This should be the optimal setting for the
> > top end of the rpm range.  Now this can all change depending on prop and
> > fuel so testing with different combinations is usually needed.  And the
> > engine will unload in the air a little too so you might have to move the
> > pipe back a touch.  At least thats the way mine setup the best.   Spins a
> > 17x12N APC @8400 on 15% Cool Power.
> >
> > Wayne
> >
> >    > Hi, All,
> >>
> >> I have a question regarding the header & tuned pipe.
> >>
> >> I will be testing a really light Tuned pipe (Japanese F3A pilot is testing
> >> the pipe on OS 140).  It is 550mm length, 48mm diameter, 18mm inlet
> >> diameter.  38g for weight.  I will have to weigh it before believing the
> >> weight of this pipe.
> >> I believe the pipe is being tested with Hatori/OS header
> >>
> >> My headers have diameter of 20mm ~ 22mm (Macs headers) that is larger than
> >> the inlet of the pipe.
> >>
> >> Does the differences in the diameter of Outlet of header and Inlet of pipe
> >> make differences when tuning for the pipe?
> >> thanks,
> >>
> >> Ihncheol Park
> >>
> >> 1973 White Ave., #402
> >> Moscow, ID 83843
> >> (208) 883-7882 (home)
> >> (208) 661-5018 (cellular)
> >> PatternFlyer at msn.com
> >>
> >>
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> >>
> >
> >
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