[spuggy]

Originally Posted by Dr J

I actually started a thread asking about high IATs but did not get any concrete data on IATs with boost whether supercharged or turbocharged.

https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/1030723-high-iats-supercharged-efi-no-intercooler.html

Don't think I saw that thread the first time. Your IATs seem insanely high, but no idea why, sorry.

Here's a log, turbo, EFI, air-to-air intercooler (Kokelyn);



Same GM sensor as you and Tippy; I get different readings second-by-second out of mine, eg when the intercooler is hot and cooling down - I've got no reason to disbelieve what it says.

Ambient at start ~23C. Highest IAT peak is 41.1C. Or 106F.

You can see it mostly recovers pretty fast driving along - the one time IAT takes longer to come down is stopped, idling - so very little air being drawn into engine bay/through the (unshrouded) intercooler by the fan.

I saw higher IATs (at less boost) chasing down a boost leak; on that log, starting with ambients of 19C, I saw a transient IAT 48.6C right after 176.8 kPa. Think the turbo was working harder...

But generally, just driving off-boost, IATs are slightly lower than ambient for me.