Thought I'd share a little project I've been
working on.
As some of you might recall, I have a burn victim
Renesis that was terminal. So I've been playing with porting the
exhaust.
The stock ports look like disasters. And they are.
They are usually packed with carbon in the upper part of the port, so that it is
even smaller than what you see here after some use. Probably not such a concern
with Airplanes and premix.
This is a four port auto low power housing.
I destroyed one end housing to find out where the
water jackets are. Then I discovered a neat trick. You can bend a welding rod
like I have here and use it to feel around and scribe where the actual water
jacket is. Then you can grind away to your hearts content so long as you leave
about .125 from that line. The castings don't seem to have much core shift or
porosity, but they are rather thin.
The port shape I show in the finished pic doesn't
leave enough support for the corner seal. I will have to do that a little
different.
I developed this port shape by the redneck flow
bench method. AKA shop vac and a thread on a stick. The shape looks bad, but it
creates two jets which run into each other head on and force the flow into the
runner. Plus the Rotor housing and the Rotor influence the flow quite a bit, so
that it isn't as bad as it looks.
It's hard to tell, but that port is much larger
than the original, plus I rounded that awful transition off.
PL got 265 hp with a Pport renesis, but I don't
think they did anything to the Exhaust side at all. Seems this is an area for
fertile experimentation.
Monty