[veloman]

I'm curious what ambient temp is the threshold where a hybrid like a gen 2 Prius can stay warm enough in city driving, so that it does not need to run just for the sake of keeping itself warm enough.

Does anyone have data on this?

I realize since I am in central TX, engine warming mods are not an area to put time into, and can be risky.

But I think i'm still going to install my own temp sensor on the engine block and see how it reacts. We do have some cold days in the winter where a simple adjustable lower grill block could be beneficial. I drove 2 miles this morning where we had a low near 50, and I got 28mpg. The nice thing about here is that most of the year it will only take a minute or two for the engine to warm up.