mprather wrote:
 >
 > What's the key to starting a P-Port without getting a dead battery?
Is the
 > variable port timing going to help. I have read about people with P-Port
 > race cars having to be towed around the track to get them running.
 >
 > Regards,
 >
 > Matt-

Good question Matt. They had no trouble starting the Lemans engine
P-port 4 rotor at the last Seven Stock. In fact there were a couple of street
cars there with P-port engines.

Electronic fuel injection should help. Unlike a carburetor  EFI takes
intake manifold temperature into consideration. EFI engines are always easier
to start than mechanical fuel injection engines for that matter.

Here are a few pictures of one of them.

The trouble with carbs is they rely on airflow to draw fuel in from the
float bowl. When using a carb for a high power engine you need a large
venturi. A venturi of a given size works well only over a narrow range
of air velocities. At low air flows the fuel signal is unreliable  so
consequently  it is difficult for a large carb to achieve a proper starting
mixture. The four barrel carb with divergent venturi sizes was invented
for that reason. Nothing to do with the type of porting other than the
fact the P-ports will flow  way more air than side ports
or a piston engines with silly poppet valves. We will find out shortly as we
are building a p-port engine. If starting proves to be a problem we will
move the primary injectors down next to the rotor housing.

Paul Lamar



Paul, just a  view into the past. Thank you for your time, and the ride.
Boberrorusa...Wichita, Ks.

That is a real old message. Since that time Mark Supinski got that
Tracy EFI p-port engine running once the ignition timing was set right.
When I left his place it would start every time on one or two blades. The
injectors are still up near the beginning of the runners right after
the bell mouths. Good starting has always been a feature of EFI.

On my new mechanical fuel injection, which is fundamentally different than
a carb, starting should be not problem. At high manifold pressure, low engine
RPM, too much fuel can be injected if you are not careful and the engine
could flood. Under starting conditions the intake manifold pressure is
always high regardless of the throttle setting. The pressure regulator
thinks the engine is running at high RPM, high manifold pressure, so
it injects a lot of fuel. It takes a rotating engine to generate
low manifold pressure.

The trick is to turn the engine over with the starter before you
turn on the electric fuel pump. Turning on the electric pump briefly after the engine
is turning over prevents flooding as you can stop pumping fuel instantly if
the engine does not start immediately. Turn the pump off and try another
throttle setting without any additional fuel at first. Different throttle
settings generate different manifold pressure under starting conditions.

It will take some applied R&D with my system to find the proper slide
throttle setting before you turn the engine over. Once that is found
turning on the electric fuel pump should result in a quick start as soon
as the mixture becomes just right.

It is conceivable there will be different optimum initial throttle settings
for widely different air temperatures and widely different airport altitudes.
One could make up a look up table if one forgets what those settings are.
Also one could note the manifold pressure with the engine turning over
with just the starter during a successful start. Shoot for that manifold
pressure when setting the throttle opening for starting the next time.

I am not using a mechanical fuel pump that starts pumping fuel the instant
you start turning the engine. That can lead to starting problems. The engine
could flood. Perhaps that explains the common hot starting problems with aircraft
mechanical fuel fuel injection systems.

BTW One of the new tricks that Mazda is using to start  piston
engines is stop the engines with one or more cylinders right after top dead center.
Inject a bit of fuel and fire it. That of course requires a computer and
direct high pressure injection.

Mazdatrix is assembling my new RX8 p-port engine as we speak and we will run it
on the dyno with a 58 mm Weber carb at first. I'll let you know how easy or hard it
is to start once we get the right jets in the Weber.
-- 
Paul Lamar ...No rotor no motor.

Paul... I'm sure you've already mentioned or have done something about it...
but... pport-engine2.jpg shows a red and white wire tie wrapped and
apparently sitting on the exhaust manifold... my experience is that the red
and white will make black in a "short" amount of running time!  (pun
intended!)

Gary Buster
Tyler Texas

No I had not noticed. Nothing I can do after the picture was taken :)
Actually I think it is an optical delusion :)