Turbo blanket
 

I came across Engineering Explained's video
Can Turbo Blankets Be Proven To Increase Performance?

Then I checked Ecomodder and turbo blankets are hardly mentioned, so here we go!

Something I haven't found in my very shallow search is whether the benefits of turbo blankets are the same for both diesels and gassers? I mean, yes, for either they insulate the hot side of the turbo, allowing it to spin faster and get a bit more boost... EE's vid uses a VW gasser as an example, but I haven't found much about diesels.

My turbodiesel already has a partial cover over the turbo, but I don't know whether it is to insulate, or just to protect from the heat? Would adding insulation give noticeable results during hypermiling, or only during high-performance driving?

The only turbo blankets that I have ever seen were more of a protective device to prevent a mechanic to burn a hand than something actually meant to increase thermal efficiency of a turbocharging setup, yet a thermal insulation tape around the exhaust pipes used to be a quite common performance-oriented mod which ended up effectively helping to keep the engine bay temperatures under control.

Back in the day there were two theories, nothing I have seen fully researched. #1: keeping the turbo input hot as possible gives the turbo more efficiency and as a result more boost since it is supposed to be a thermal driven device. #2 keeping the exhaust hot aids flow out of the system and aids sensor function. Insulation on both keeps the engine bay cooler which again, in theory, promotes charge density.

Not sure about aiding sensors function, but the catalyst may reach its optimum temperature sooner when heat is retained at the exhaust flow instead of irradiating through the entire engine bay.

But aren't we, Ecomodders, already struggling with keeping the engine warm, so a warmer engine bay would aid that?

Yes it's hard to keep the engine warm and the intake air cold but not impossible. Snorkel style intake for one, ram air from rearward facing scoops just under the windshield....

Other than building a box, not sure what would help the engine

I run a manifold and turbo blanket on my Talon during the Summer and hot Fall and Spring days. I pull heat off the lower side of my Exhaust manifold to increase the IAT'S up to 250*F. for FE.

One thing I did notice is that it does lower the life of the turbine housing. After three years the turbine housing developed cracks.

Does a Rear Mount Turbo have a Lot of Lag? Remote Mount Turbo Benefits and Drawbacks Explained
three turbos in the pickup bed

Here is one of the turbine housings that cracked that I was talking about. Attachment 34498

I remember reading articles about remotely-mounted turbochargers and, besides the lower heat irradiation through the engine bay, which might be quite a PITA to overcome in some small cars, the extra piping required actually worked in a way similar to the intercooler of a normal turbocharging setup, as it increased the surface area for heat exchange and the longer distance provided for a natural cooling of the intake charge.