I went to some of the RX 7 groups online to find out the best way to
control
 FI.I am looking at Megasquirt as a plan B or C if the 555 analog system
does
 not work out.I guess there is manifold pressure which is not stable on a
P
 Port.Ther isMass air flow which is being proposed for the 555 system
and is
 supported by Megasquirt.The RX 7 guys seem to think the MAF sensor could
 impead the air flow to make big horse power.200 to 250 HP does not seem
to be
 big HP when they are getting a lot more out by turning the engine faster.
How
 does TPS or throttle position sensor fit into this?Thanks for any help

 Joe Berki
 Limo EZ 13b P Port



 As long as the mass airflow sensor is around 5.5 square inches it should
be
 fine.
 That is something about 2.625 or 2.75 inches in diameter will give around
 250 HP. The throttle position sensor will not work with the 555 system
 not is it needed.
 --Paul

 Paul

 How would themass flow sensor work with a turbo charger on the front
 end?I Think that the MAF sensor would be calibrated for ambient
 pressure N/A applications.

 Doug in Japan

 The 555 system has a provision for scaling the airflow signal.
 The gain of the op amp can be adjusted.
 It responds to mass flow only and not pressure per se.

 Paul Lamar


How will the MAF signal be steady in comparison to the manifold pressure?
Where is the best place for the MAF sensor after the air filter?
Joe

The mass airflow sensor is a hot wire basically so it heats up
and cools down rather slowly. It responds to the average flow unlike
the manifold pressure sensor that changes in one one thousands of
a second.

The best place for it is after the filter ahead of the plenum
so it measures all the air coming into the engine. Here is a 3D
showing the old style 2nd gen trap door mass airflow sensor.
The newer mass air flow sensors are mostly just a large tube
about 3 inches in diameter and several inches long.
The Ford Escort shown is a bit small.
The air filter is not shown yet.

Paul Lamar