Optimum Operating Temperature

[Parker]

As I type this my Hans Gauge is winging it's way to me, may even be on the door mat. My weekend job is sorted ;)

My Question is - What is the optimum operating temperature range for my 1.8T ?

[T-Cut]

My Question is - What is the optimum operating temperature range for my 1.8T

From my investigations, internal combustion engines (petrol and diesel) run most efficiently at 95-100°C.
My 1.8T hovers mid-way in that range when cruising normally. Running at 30mph or less raises the temperature due to lack of airflow through the radiator. The slow speed fan comes on at 107°C and switches off again at 97°C. More details here: http://www.the75andztclub.co.uk/forum/showthread.php?t=29584&highlight=monitoring+engine+temperature

TC

[Parker]

Thanks very much for info T-Cut.

[kaiser]

The optimum temperature for a petrol engine, is in the region of 90 to 100 degrees.
The higher the temperatures, the lower the loss to the water. But also, the less safety, before something goes wrong.
The cooling water temperature has tended to creep up slightly over the years, but this requires increased control (possible with computers and fuel injection and adjustable timing) to keep things in check.
I would rather run at a couple of degrees lower with these engines where cast iron liners expand less than aluminium, and where the cooling system is rather marginal, and I would start to worry if I see anything more than 105 degrees.