Averaging Coolant temp

[Anthony Parle]

I have two temperature probes on e into each of the back of the head on my Subaru engine, is it possible average these in some way to use in the main control of the engine?

 

[Adamw]

Hi Tony,

I'm not sure there is a way to do this in the software at present as its probably not something many people need to do.  I'm sure it could be done electrically though - without giving it much thought probably something as simple as wiring them in parallel (or would it be series?) and write your own cal table for the combined sensors. 

I am curious how much difference are you seeing?  Since engine temp is normally only used for comps like warm up enrichment and charge temp its probably not too critical to be a really accurate measurement, I would have expected just one sensor that follows the general temperature trend of the engine would suffice in most cases?

[Anthony Parle]

Hi Adam,

I see around 10 C difference between the heads, Subaru and I totally disagree on the way their engine cooling system is designed.  Things like thermostat in the bottom of the engine not the outlet of the engine like every other car has.  I only know of Porsche that have the thermostat in the inlet, everyone else is smart enough to have it at the top outlet of the motor which makes sense.

There are a bunch of other problems with there cooling system to long to go into here.

By the way Adam the TPS tuning is going great, thanks for your help.

[Scott]

Another option would be to run the 2nd ECT sensor as a 'GP Temp' and then allocate a 4D/5D fuel table axis to it.

Scott

[Anthony Parle]

Hi Scott,

Right now I have a average temp probe which is on the outlet manifold its just that with the 3 I have plus oil temp I have used them all in the Thunder.

For every ones general knowledge if a Subaru engine blows a head gasket you can see it straight away in the cylinder temp on that head.  Guess it would be the same on any V type of engine.