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Al, I think you are
Ok measuring at the intake ports. My two computers use the two
extremes. My system:
Controller A:
uses the stock intake manifold MAP port which is actually inside the stock fuel
injector bores on the center housing. You cant get any closer than
that. This MAP line is T'd with the fuel pressure regulator and the sensor
for the engine monitor.
Controller B: uses
the TWM MAP ports which are just down stream of the TB valve and upstream of
very long runners (about 28" - because that's how I could get everything to
fit). The MAP line is T'd to both runners and to the
BOV.
Controller A, the
closer one, actually works best for idle, Controller B seems to work best for
lean cruise (another area where rough running issues begin to pop up). At
first the difference was fairly significant, but now both controllers are nearly
equal so I think maybe I am only imagining the difference.
Now that I think
about it. Adding the BOV really seemed to improve the idle performance of
controller B. That is, adding another foot of MAP line with a small
chamber at the end made controller B idle as well as controller A, which already
had an extra foot of line going to a small chamber in the fuel pressure
regulator and another to the MAP sensor for the engine
monitor.
During testing, I
could not get the engine to run well at all if the MAP lines were only connected
to just one of the TWM ports. Now that I look back and add it all up,
I think the jet/filter idea is the way to go. Probably just the filter
would be enough and easier to install. Who tossed in that idea, was it
Bulent?
Dave
Leonard
Hi Al,
Here's a clip from I email exchange I had with
Tracy a while back. For
me the trick to getting a smooth idle and a balanced
mixture between
rotors at high power was to measure the MAP right
behind the throttle
body so to minimized the effect of the pulses in the
runners.
The MAP ports are just
downstream from the TB. The difference is that Tracy’s TB is way out there BEFORE
the runners. Mine are about 5” from the rotor housing, and downstream
from what are effectively short runners – the TB barrels. I guess it
could be that there is very short term variations in the MAP
readings.
Is there a pattern
here? Are all those of us seeing rough low-MAP issues measuring MAP
nearer the intake ports? Let’s see; Rusty, Dave. . . who
else?
Al
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