If you guys (Ed and Al) don't
mind, I'd like to propose a test. At your convenience, and I'm not
kidding- don't make any special trips, or go to any real effort. Could
each of you run at low power, below the staging point, maybe 1500 rpm, and
enable only one set of injectors at a time. I'd be interested to
see what position on the mixture knob you have to use for each set. On
mine, I have to turn the mixture knob to about 9:00 for the Mazda 550's, and about
3:00 for the MSD's.
The test will be interesting,
since (as I recall) Al has Mazda 550's as primaries, and also has the
same MSD's that flow about 500 as secondaries. I can't recall if I've
ever seen the physical layout of these though. Are they all the
same distance from the rotors?
Sorry, it will be
months yet until my engine runs again. It ran on the dyno, now waiting
to run on the airplane.
RC Engineering
measured 570 cc/min on my Mazda injectors that I used as primaries. I
have no measurements on the MSD 2013s. You can see on the attached photo
the 570s are in the rotor housings and the 2013s are out in the TB.
I’m not surprised
at your mixture knob settings. Mine were even more extreme. I
don’t recall ever running on the MSDs only below the staging point. For
the 570s I had to turn the mixture knob as far as it would go to get enough
correction at idle, and then it may still have been a bit rich. But I
was running with a constant pressure fuel regulator at 40
psi.
I’ve changed to a
MAP referenced regulator, and I’m planning on switching the wiring to run the
MSDs as the primaries (if my wiring harness allows; I have completely separate
wiring to the two sets coming from different sides).
BTW; a plug for TWM
Induction. I returned my constant pressure regulator and they very
promptly swapped my old fittings into a new MAP referenced body and returned
it to me – NO charge. A bright spot in my day.
Al