12 F

 Paul,  getting bored so to occupy the time I am looking at the
 complications for adding a turbo to a P ported engine. Not wishing
 to blow the backside out of the engine, but a gentle 5 pound boost.
 How do I size a turbo for this to occurr?  There are plenty of Ford
 RX7 turbos out there (Chinese)  for $300.  Not that simple, so what
 parameters are needed?

 Neil Unger


 Use the biggest turbo you can find and use a blow off valve on the
 intake manifold set to 5 psi boost. The big turbo will have an easier
 time of it with the 1800 degree F Wankel exhaust temp. Also use a
 vent on the exhaust manifold with a 1.25 inch diameter hole. Forget
 the waste gate. It will do nothing. Turbos work and spin  on exhaust
 mass flow and not exhaust pressure.

 The video show water vapor coming out of the blow off valve with the
  engine running at full boost. You may or may not need a intercooler.
 With only 5 psi boost and silicone nitride apex seals probably not.
 Silicon nitride apex seals are essential with any boost.

 Paul Lamar


Paul,  This seems all wrong, but obviously works.  What you are
suggesting is----- To forget any wastegate which gives all the exhaust
ports channeled into the turbo, but with a 1.25 inch bypass to simply
reduce the amount of exhaust going through the turbo by possibly 1/3?
You look to have just exhausted the by pass to the open air?  Should
that pipe be muffled for noise reduction, or just piped back into the
exhaust post turbo?
    Then you suggest a blow off valve to prevent the boost climbing
past say 5-6 pounds in the pressure side??
This,  if I am correct in following your instructions does make a simple
install.
Does it matter just what degrees the P port opens and shuts?
Did you find a exhaust temp sender that survived the heat?  I managed to
burn all mine off eventually.
Forgive all the stupid questions, but this differs totally from any
turbo install I have seen, but then it is not in a car.  The application
is totally different.

Neil Unger.


You don't get a lot of noise out of the bypass.

The thing about computer controlled waste gates is they are designed for the automotive environment.
You need max HP instantaneously to accelerate a car is closed. In an airplane that is not required.

So it takes a few seconds for the power to build in an aircraft engine. No problem.
The power will build until you achieved the desired manifold pressure and HP
controlled by the blow off valve. Then you take off.

With a blow off valve on the intake manifold you will never over boost the engine.
With a computer controlled waste gate it is possible to over boost the engine and
cause it to fail if the software (software bugs)  fails or the waste gate fails to open.

Use the Le mans p-port port timing. Mazda spent a lot of R&D on optimizing
the BSFC.

Paul Lamar


 ------------------------------------------------------------------
 Please  add your questions or comments  at the end of the thread. Not
  the beginning.

 I am going to enforce that rule. If people don't do that it will not
  be published. My ISP changed the rules.

 The Rotary Engine free News Letter. Powered by Linux. If you want off
  the list PLEASE let me know and I will remove  you.

 ACRE NL web site. http://www.rotaryeng.net YouTube  Key word
 "PaulLamar2". Keep clicking this as Youtube will try to divert you to
 advertising. Copyright 1998-2018 All world wide rights reserved.