Mark,
You have a lot of fuel delivery
capability, but you may have too much. Just the three primary injectors
will provide 190 HP at an 80% duty cycle, and about 230 at 95%. Assuming a
.55 BSFC. When you kick in the secondaries, your duty cycle drops way
down. Even if you are making 350 HP, your duty cycle for the 6 injectors
you are using is just a little over 60%. And depending on how they are
controlled by Tracy’s
EC-3, the secondaries may be being cut almost out. If the EC-3 maxes out
the primaries, those huge secondaries would barely be turned on. They are
not accurate at low duty cycles.
You may have dirty or plugged
injectors. I had my injectors cleaned and flow tested at
CruzinPerformance. (link is below) it is really not too expensive
and at least you will know what you have. That will help you to set your
MAP up as well.
You can probably rig up some kind of flow
test bench yourself if you are wondering what they look like. See the link
for WitchHunter to see how it could be done. He doesn’t tell you
how, but explains enough to make it possible for you to figure it out.
Which injectors see the fuel supply
first? Can you be starving the last two injectors? What fuel
pressure are you running? Which size fuel pump are you using? Does this
problem clear up if you turn on both pumps at the same time?
I don’t understand the reasoning for
the injectors being prior to the throttle body. It seems that you will be
injecting into a slow stream of air at any time that you are not at WOT. I
realize you are trying to get the throttle body as close to the PPort as you
can, but why not have both injectors behind the throttle? I would expect
that the throttle butterfly would cause fuel to come out of the air stream??
Does it, or does the stream speed up enough to keep it from coming out?
http://www.witchhunter.com/process2.php4
http://www.cruzinperformance.com/
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mark Steitle
Sent: Monday, May 28, 2012 9:38 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Injector
balancing
I'm in a bit of a dilemma and thought I would put this out here
for the group to ponder.
First, this is a p-ported 3-rotor, running RWS EC-2 and psru. I'm
running 460cc Mazda primary injectors and 60lb Deka IV secondary injectors.
Primary injectors share a common fuel rail and are positioned close to
the engine, between throttle plate and rotor face. Secondary injectors
are located ahead of the throttle plates. As this is a p-port engine, it
has three 1-bbl TB's, located very close to the engine. Engine will idle
down to 800 - 900 rpm, but I normally idle it around 1500 - 1600 rpm.
The problem is this, the #1 rotor cuts out at low to mid-range RPM, evidenced
by obvious reduced power, very low EGT's on rotor #1, change in exhaust tone, a
dark residue in the #1 exhaust port and dark spark plugs on #1. Just
today I was able to get it to run normally with balanced EGT's by adjusting
Mode 4, but I had to go full CCW with the program knob to achieve this.
(Mode 4 & 5 adjust similar to Mode 1) Now it runs well
mid-range and the dropped #1 rotor is happily firing away. I still have
some tuning to do, but after adjusting Mode 4, I can now move forward with
that.
To date I have tried the following:
1. Performed a compression check - OK
2. Swapped primary injector with #3 - no change
3. Swapped coils with #3 - no change
4. Replaced spark plugs - no change, except initially it
ran better until the plug fouled
5. Checked plug wires with ohm meter - checked good
6. Sent EC-2 to Tracy
for latest s/w and checkout - no abnormalities found, latest s/w installed
7. Checked secondary injectors for leakage - none seen
Can anyone suggest a reason why the #1 primary injector runs extremely
rich when set to the factory default setting? Is this something to be
concerned with?