Greddy Pressure Sensor – This is a 3-bar air pressure sensor add-on.
With it, you can tune your fuel maps with this sensor's output as the
basis for tuning instead of the car's airflow signal input. This is
primarily used when you've overrun the capacity of the stock airflow
meter. Whether or not you need this is a tough question – it's really
best to run the car without it first and see if you're maxing out the
stock airflow meter signal before investing in the pressure sensor.
Retail price of the sensor is $120, with a street price closer to $100.
NOTE – the peak/hold/warning Greddy boost gauge uses the SAME sensor,
so you can share that sensor's output with the E-manage.
The best setup to start with is the main E-manage computer and the
Support Tool. Next would be the injector harness, then the ignition
harness, then the pressure sensor. If you need control over ignition
timing as a priority, you might want to look into the ignition harness
first over the injection harness, or do the trick below to use parts of
the ignition harness as the injection harness. Regardless, the
pressure sensor is probably lowest on the priority chart - it's moreso
something you get when you know you're overrunning the stock airflow
measuring device. It might be more of a priority if you have a non-
turbo car with a turbo kit and the stock pressure sensor for the car
doesn't read boost pressure. Again, it really comes down to what
you've done to the car, what you're planning to do, and what you want
from the E-manage.
7. Tuning and Using the E-manage
One big source of confusion on the E-manage is its ability to let you
use different airflow meters. While this can be done, there are some
limitations and rules to play by.
First off, you can only change an airflow meter for another meter of
similar type. For example, if you have a hotwire airflow meter, you
can use ANY hotwire airflow meter, even if it's from another
manufacturer. The software/firmware only has Japanese airflow meters
listed - US AFM's could be used in theory, but you'd have to find its
Japanese equivalent. Anyhow, if you have a flap-type airflow meter,
you can only use another flap-type; if you have a Karmann, you can only
use another Karmann.
This option might be helpful for Subaru owners who have had problems
with less-than-durable airflow meters - might be able to swap to a
Nissan unit, or even another Subaru unit that's hardier. It's also an
easy way to upgrade - Nissan has 80 and 90mm airflow meters!
Second, you can't get rid of the airflow meter and use a MAP sensor.
Even if you add the optional Greddy pressure sensor, you must still
have an airflow meter in the system. The Greddy pressure sensor simply
adds another basis for your fuel maps in the E-manage - you can use it
to tune your fuel maps instead of the input from the airflow meter
(very useful if your airflow meter has run out of range), but that's
all internal to the E-manage.