I have a question about that. You mention little heat transfer at WOT, I believe you on that but what about a DD, for example, sitting idling in traffic, surely that has to heat it up more? Or the incoming air will still pick up tiny amount of heat but not a lot compared to other parts?

When you're idling in traffic, your engine coolant will actually COOL the TB. So why would you want to block it off or isolate it?

Well, there may be ONE potential benefit for an L36 to blocking off coolant to the TB...

If you block it where it enters the UIM / exits the LIM (so that it never gets to the area around the EGR pipe), perhaps you can avoid "drinking the Dex-Cool-Aid" during the inevitable UIM meltdown.

But then again, does HAVING that coolant flow through there help prevent the UIM meltdown?

Opinions?

If you consider the EGR temps in close proximity to the composite material of the L36 UIM, one would think that coolant under 200° F might prevent some breakdown. Is this necessary if your UIM is sleeved? Probably not.

I think everyone can agree that no matter whether the coolant runs through the TB or not, there is no plausible way or reason to cool the TB from outside heat sources, as tested by willwren. Attempts to block the coolant seem to have no effect other than waste your time.

P.*. if you can afford to fabricate a 3 foot TB spacer, then you can afford to upgrade your supercharger.