Vans RV-12 Engine Data

[2626jerry41]

The temperature readings for both cylinder head and oil temp are running in the yellow when operating in air temps that are 75 F and above. Another RV-12 flying in the same air temps are 5 to 10 degrees lower. The EMS was set up using the default settings offered by Dynon for a 912. Do the default settings for the cly head temp take into account that the cly head temp probe is actually measuring coolant temp? The right cyl head is typically 4-6 degrees higher than the right. Both engines have more than 50 hours of operation. The Rotax manual gives max cly head temps while the probes are actually reading coolant temps? We are running the latest software version. The cly head temps that we are reading are not close to the max temps specified by Rotax yet the color bars are displaying yellow. Any ideas out there ?

 

[Dynon]

So having not looked at the 912 pre-sets in a while, MAKE SURE, by checking against YOUR ENGINE's manual, that the numbers are right. When they were created, they were designed to use the exact numbers that are in the Rotax book, but it's possible there are mistakes in our setup (this is why we explicitly say "These files SHOULD NOT be considered complete. While efforts were made to set up temperature, pressure, and other ranges to reasonable starting points, Dynon makes no claim that they are correct for your engine, as slightly different engines may have different limits. Check EVERY setting before operating your engine with them."

As far as Rotax is concerned, those probes that are in the heads and are the CHTs. So their numbers should take into account all of the variant factors.

 

[Dynon]

So there are a bunch of numbers for CHT and coolant temperature specified, depending on whether you are using waterless or conventional coolant, and then depending on the precise model of engine. Those numbers can be 248F, 275F, or 300F, depending. To be conservative, our pre-set files uses an even 250F as a baseline.

 

[dynonsupport]

And, more important, the limits we use are the ones that Vans wants us to use.

 

[Battson]

It's worth saying that if you want your engine to last long and give extra hours of valuable and reliable service, you can do more than just get 5-10 degrees out of the yellow zone.
There is no good reason why you shouldn't be operating in the middle of the green range for 80% of operations, if you keep working at it and tuning the cooling systems.