I started the car for the first time since R&R and did not have the turbo connected.It spun freely and discharged to open bay.
The compressor housing was warm after engine warm up and the air was warm that was compressed ...a little milder than you hair dryer.
Is this from the heatsoak from the turbine to the compressor or just the compressed air raising the temp?Or is this from the combo of both. The whole clam was warm.1st time I've had a chance to observe this. It would seem that a heat sink would have been developed for the CHRA to compressor.Like the LMS heatsink.
Just curiuos

 

Since the turbo inlet and outlet are open to atmosphere, the turbo is just moving the air and not compressing it as there is no air flow resitance on the output to cause compression.

From this the answer should be obvious which you already stated, heatsoak.

 

Not really true! I've started my cold fd with the stock twins turbo outlet tube disconnected. Rev ed it a little bit and noticed a higher temp out the outlet pipe when the turbo spooled. No heat soak at all. The air is still being compressed in the compressor housing.

 

I have to go with Chuck on this one, with no restriction, the air even if locally pressurized in the housing, comes out under free expansion (how many psi do you really think the air is hitting your hand at to cause a noticeable by you change in temperature?)

The heatsoak would seem like a no go as well because of time associated with the air going through the compressor housing does not allow for a substantial/noticeable amount of energy to enter the air ie working fluid.< hey that a technical term

So without measuring the change it is probably mostly in your head.

 

A healthy stock car will make 5 psi by reving it to 5k in neutral. My hood was open the whole time and there was no heat soak at all when I did it. Also the air was cool comming out the outlet before I reved it.

 

Well , FYI
The discharge temp does increase with the heat soak into the compressor.Maybe both are synergistic to this occurence as idle time and engine temp goes on. I wonder how this effect
is multiplied under boost and restriction.Remember even the compressed air is being forced at a high rate for a miilisec through the intercooler and it has a heat exchange effect at that rate.
Just an observation several of us made at the shop today.