The Racetractor. The End.

[Ruan]

I've sorta recommended to James to use the flow from the back of the cylinder head to the heater matrix to put through the turbo - it should be ~82*c under normal running conditions, and it'll warm up fast. The water will ALWAYS be cooler than the CHRA - putting cool water flow post radiator is likely to thermal shock it - the greatest damage is done with changes in temperature.

I'd be very worried of having it post thermostat, especially on a Diesel - they take so long to truly heat up and the thermostat is often cutting in and out to maintain the temperature - you're likely to have essentially no flow, then bring the engine to FULL power, until the heat actually comes off the cylinder head into the coolant, finally warms the thermostat, it opens, then you get water flow - by that time the turbo is absolutely cooking hot, you're likely to have boiled off the coolant in the CHRA before the thermostat even opened and let water through. Especially in winter when you've got the interior heaters blowing red hot - you can get to the point where if the engine is under low load, the amount of heat generated isn't even enough to open the main thermostat, you end up cooling the engine just with the heater matrix!

I know the J2TE and CDTX etc have it post thermostat, however those engines have a much more stable coolant temperature since they dump so much more heat into the coolant- once the engine is warm, the thermostat is generally at least open a percentage all the time. I guess it's a big disadvantage of having such high thermal efficiency in an engine.

I'd be interested to see how Volvo originally plumbed those units in.