> Ken,  There are no test results.   It is all theory  and wishful > thinking at this time.  Bob White bought an exhaust system, even > though it is unproven, and he will be the first to test it.  I am
> sure >  your comments have gotten  his attention today.  I forget how long >  > the tuned exhaust pipe is  supposed to be.  I do recall  it was long
>  enough there was no hope of getting one inside the cowl and then
>  there > is that muffler hanging out in the breeze. I can't see that on a > Tailwind.  Drag and weight are penalties of the tuned exhaust. As
> far  as performance is concerned it might be a wash.  No one knows
> until we  do the tests.
>  BTW,  the exhaust pipe on my system has much greater capacity than > the combined two inch pipes of a tuned system.  Easy breathing is
> what  I am hoping for.   Jerry
>

On Thursday, January 6, 2005, at 02:04  PM, kenpowell@comcast.net
wrote:

> Hi Jerry,
> As you know I am also a great proponent of Pport.  Since I am
> building  a RV-4 room is a problem under the cowl (Rusty knows what
> I mean!).   While your exhaust would solve many problems for me I
> think you are  going to be disappointed in the HP output without the
> scavenging  effects of a properly tuned (and pipes merged) exhaust. > I hope you  prove me wrong, but I hope you are flexible in your
> design to add full  length pipes.  I suspect the untuned exhaust may
> cost as much as 30 HP  (yes, this is a real swag without any data to
> back it up so it isn't  worth much).  Do you have any test results
> (from anybody) to show the  results of a short untuned pipe?

> Ken Powell
> Bryant, Arkansas
> .
>

>
> -------------- Original message --------------
>
> >
> >
> > On Thursday, January 6, 2005, at 01:28 PM, Russell Duffy wrote:
> >
> >
> > My p ports open at 78__ BTDC and close at 75__ ABDC. This
> > drawing shows how much later the ports open in comparison with the
> > Leman P Port and how they close at nearly the same time. According
> > to calculations made by Rolf Peiffer who helped me a lot, my
> > little port has sufficient capacity up to 8000 rpm. After that you
> > would want to go bigger. The exhaust port was left stock with the
> > splitters in. . JerryArialFFFF,0000,0000
> > r>
> >
> >
> >
> > ArialFFFF,0000,0000Thanks
> > for the info, and pic Jerry. Do you have an estimate of how much
> > HP you expect to make at 7500 rpm? And can you get that thing
> > running in the next month, so it will be easier for me to decide
> > what to do :-)
> >
> >
> >
> > ArialFFFF,0000,0000Cheers,
> > or>
> >
> > ArialFFFF,0000,0000Rusty
> > >
> >
> >
> >
> > Rusty, The hp question???? A worse case scenario I feel would be
> > 230 hp at 7500. I think around 250 hp is realistic if we can get
> > it up to its potential. It depends on so many factors that will
> > have to be ironed out on the dyno. I have a 2:17 drive and a 800
> > lb airplane so if I equal PowerSport's performance of 215 at 6000
> > that would be sufficient to get the heart pumping on climb out.
> > That said, I think PowerSport's intake is too long and also they
> > could benefit > from
> > ram air. So maybe I will do a little better then they have. My
> > exhaust is a free flowing, zero back pressure design and I am
> > hoping it will help too. Best thing for you to do is to haul that
> > engine to Lynn"s and knock out a p port in a couple of days. Jerry
> >
> >
> >
> >
>