Fully agree on 4 probes, as one tells ya' absolutely nuthin. However,
on the Rotax where you can't adjust mixture, all EGT tells you is
impending upper cylinder problems and importantly who's the culprit.
Arguably nice to know, but the Rotax service record is excellent.
Switching 4 EGT probes can degrade accuracy a lot, and 4-probe
displays are very pricey. If one is handy with electronics, all you
need are 4 little LCD 0-200mv display modules ($10-$25 a pop). Plus,
they now sell high-temp thermocouple probes (c. $25) for digital
multimeters that, with aid of a torch, you can calibrate and thus
equalize the 4 modules. The absolute accuracy of any one cyl's
reading is not as important as comparative temps.
Regards,
Fred F., A063
Graham Singleton wrote:
>
> >CHT ( looks like 1 sensor on the standard installation. Anyone do all 4?)
> >EGT ( looks like 1 sensor/side. Aren't 4 needed?)
>
> I would strongly recommend 4 EGTs. They don't half dance about with changes
> in throttle setting. Probably due to the manifold/butterfly interaction. It
> may be less of a problem with the 914 because the inlet air temp will be
> higher and help to evaporate the fuel droplets and distribut the fuel to
> the cylinders in a less random manner.
>
> Graham.
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