Paul, throttle response of our peripheral port engines was very good on the
ground and in the air, and at any point throughout the operating range. No
discernible lag. No stumble with throttle advanced from idle slightly or
full throttle when on short final, etc. so made it very nice to fly. Idle
speed approx. 1000-1200 engine rpm. But we had the throttle shaft and
plates located inside the rotor housing. Although locating the throttles in
the rotor housings is probably the optimum for response and idle speed, it
involves a lot of work. Putting a slide or throttle-body with plates/shafts
just outboard of port probably next best location.

Steve Beckham

As I recall Mazda placed the injectors close to the P-port on the Lemans
engine for throttle response reasons as it is very important when road
racing.

http://www.rotaryeng.net/Mazda_R26B_US.pdf

Also it might be a good idea to use a Megasquirt in this application.
The 555 system and Tracy system has no provision for rapid engine
acceleration.

We did discuss it at one time by putting a special switch on the throttle
knob to
temporarily enrich the mixture.

"Basically it is short stroke pancake air cylinder mounted on the slide
throttle
knob inside the cockpit with a small air hose connected to the back
side of the diaphragm in the Tillotson type carb. The increased air
pressure
will inject an extra shot of fuel and open the supply needle valve at the
same
time. When the knob is released the diaphragm spring will slowly restore
the diaphragm
and close the needle valve again.

Something like a 1 inch bore (2" OD) cylinder with a .5 inch stroke
or smaller should do the job. A spring inside the cylinder will restore the
stroke after the knob is released. A one way valve on the intake port to
the cylinder  will fill the cylinder with air."


Paul Lamar


Paul and group,
Every racing and street EFI that I have encountered has a throttle
position sensor. The rapid opening of the throttle at low RPM should automatically
enrichen the mixture. Since the injection is a demand system based on RPM
of the pump, and the stroke or the time of opening the injector, the
throttle response should be better than any carb system. Airflow performance type
systems use the differential between the servo pressure and the inlet
pressure to do the same thing. Hilborn style systems connect a valve directly to
the throttle shaft that does the same thing. (I know Paul knows this
already but it should be built into any EFI system.) The basics of fuel
injection is so intuitive that it is supprising that the carburetor came first.
Even a system without a throttle position sensor should have programing
ability to richen using the map sensor. Older alpha-n systems used only a TPS and
RPM with a programmed fuel map. We are talking about making a injector
pump like used in a carb. This shouldn't be needed in a EFI. Just my $0.02.
Bill Jepson

    
I have an RWS EC2/EM2. I am not familiar with the electronics and input options available but I am assuming there is no TPS input on the EC2. I recall some discussion on the early p-port prototype( perhaps Mark's) involving issues with EC2 tuning. Has this been overcome or am I best to obtain a Megasquirt .Any concerns with the Megasquirt reliability or redundancy.

Thanks for your time guys


Geir Andersen   

Yes you are right there is no TPS. That is the EFI that can be tricked with the                 air cylinder however.

Set it on the rich side in the 1500 to 4000 RPM range and try that first.
Slam the throttle open and see what happens. If it does indeed run rich
yet stumbles when you slam the throttle open then that is the time for the
air cylinder. The sudden increase in MAP will trick the EC2 into thinking
it needs more fuel.

Mark Suspinski, How are your AC repairs coming? Have you tried slamming the throttle
open from idle?

Paul Lamar

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