You are right on target Chrissi.  This is precisely what Mazda did

in

the

normally aspirated rotary.  They call them exhaust splitters and you

can

see

them in all 6 port engine exhaust ports.  They reduce exhaust

impulse

energy

by 10 db.  That means it reduces the impulse energy to about 1/3 of

what

it

is in the turbo engine.  Wish I had them in my engines :-(

Tracy Crook

Tracy,

Did your first engine (the one you were using when you made the manual)

have

the exhaust splitters?
Wendell

Yes, the first engine (856 hours) had the splitters.  My noise & muffler
problems began when I changed to turbo exhaust ports in the second engine.
Even though the Spintech muffler seems to have it under control now, I still
think the splitters are a good idea.

No dyno data, but I don't think the open turbo exhaust ports gained
significant power.  I estimated an increase of maybe 5 HP with the new
engine but this is comparing a primo 0 time engine with higher compression
rotors to a junkyard dog engine with a guick & dirty overhaul (apex seals &
oil seal O-rings replaced).

I did gain significant power later with the addition of a header & collector
exhaust system (about 15 HP).  The question of course is, would the splitter
exhaust engine have benefited as much from the better exhaust system? My
guess is that it would have been close.   Comparing different configurations
is where dyno testing is really valuable.  Dynoing an engine in one
configuration just to get an 'official' number on it is kind of a waste.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

 
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