question regarding header & tuned pipe

[Bill Carpenter]

Wayne,

I think you're right.  I forgot that we in pattern aren't necessarily
interested in "peak" rpm.  I think my limited racing background must have
let me astray.

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, 9:33 AM
>

> 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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