Hello Christoph,
I also have the GRT EIS 4000 (I am very pleased with its performance),
912ULS and XS firewall-forward kit from Europa. Please see the attached
photo for where the aft EGT probes are mounted - no double side flange on
the exhaust tubes, though, as far as I can see on the photo.
My EIS set came with 4 ring terminals, of equal size. They are
thermocouples to be pressed against the cylinder head metal, under a bolt to
be screwed into the threaded holes provided for the standard Rotax CHT
probes. The standard probes measures the temperatures inside the CH cavity,
while the ring thermocouple will be exposed to cylinder cooling air.
Therefore, you must cover the thermocouples and the adjacent CH metal well
with a suitable compound (I used the red high-temp silicone from Loctite).
There is a noticeable difference in measured temperature with and without
this insulation against air cooling (I did not have it at first). See
attached photo.
I have not fitted any probes between cooling fins.
Since I operate my engine with 50/50 glycol/water, I have also fitted a
coolant temp probe into the hose between one of the cylinders and the small
black "bottle" on top of the engine (as per Rotax recommendation). This
probe is connected to one of the available input channels on the EIS.
Why there is one large and one small thermocouple in your set I do not know
- it should be 4 of equal size to fit under the head of suitable bolt.
Suggest you ask GRT about this.
As you probably know, you must not cut and splice the thermocouple cables -
they must run from the instrument to the cylinders just as they came from
GRT.
Regards,
Svein
LN-SKJ
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