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Europa-List: Re: 914 CHT

Subject: Europa-List: Re: 914 CHT
From: h&amp;jeuropa <butcher43@att.net>
Date: Fri, 10 May 2019 06:14:31

Hi Bill,

GRT EIS has several dedicated inputs: CHT, EGT, Oil Temp, Oil Press, Volts, RPM,
Carb Temp, OAT, Coolant Temp and Fuel Flow.  By dedicated I mean the software
is programmed to expect those inputs if sensors are attached. You do not have
to define them to the software.  Likewise you do not have to use them either.

Oil Temp and Oil Press use the VDO sensors supplied with the engine.  Volts is
measured internally from the power input. RPM uses the Rotax supplied tach 
signal.
The others are optional and use sensors available from GRT (most of which
are VDO sensors).  When you purchase a sensor from GRT it will come with data
specifying what the Scale Factor and Offset for that sensor should be set at.

CHT requires Type J thermocouples  and EGT requires Type K thermocouples.  GRT
supplies CHT thermocouples that are ring style P/N CHT 10-01.  Rotax supplies
the engine with VDO resistive CHT probes that thread into the cylinder head. 
These will NOT work for GRT CHT.  You can use them to secure the GRT ring 
thermocouple
or remove them and secure the thermocouple with a M10 bolt.

Any Type J thermocouple will work and you may be able to obtain them locally. 
I'm sure GRT has them available and shipping should be reasonable.  Be sure to
use thermocouple extension wire (not common electrical wire) if needed.

The VDO sensor currently in port cylinder head is the same as the one used for
oil temp.  These have become quite expensive lately, so be sure to keep it for
possible future use.

GRT EIS gives you six inputs you can define and use as you wish.  Most have 
sensors
available from GRT.  In my case I use my inputs for Port fuel qty, Stbd fuel
qty, Man press, differential fuel press, amps and cowl flap position.

By Rotax control box I assume you mean TCU, turbo control unit?  It does not 
have
any provision for CHT input.  It comes with a harness from Rotax with 
connections
to the airbox, throttle position sensor, ambient pressure and  air box
pressure.  The TCU operates the servo motor which in turn operates the wastegate
of the turbo.

I hope this helps.  Manuals are online at GRT and I can answer most questions (I
wrote several of the manuals).

Jim Butcher


Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=489158#489158



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