Thing is, on subarus the TB is right above the engine. On some cars they're on a long runner away from the engine an it's totally possible it would freeze open.
on the old subes the more heat taken away at the base the better. I pegged an ea82 to 38mpg all year round. (I was modding for hypermile) with an spfi blocking coolant. Cannot compare to inlne fours, at all, ever.
The carb subes still do good with or without...I do admit I need a heat rise pre-WOT, but then again, it still goes good, I'd only want it for more heat for me inside the car.
the ej has huge air.. it is even an inspiration to keep EGR working.(and that is an engine kill)
in the past 13 years, I have driven through two thermal records not broken. One was -28F brewer maine, and one was -18F.. that cold in real means no heater keeps up.
On the carbs I leave the coolant at the base .. on the spfi I block them. Fuel injected has a lot of hertz.. it is nearly impossible to freeze, as hertz equals movement, freezing needs still. Unless it is an inline engine with dangling intake off the side of the engine (like uhh... all of them), in that case I have frozen all versions I have ever run. I wondered if that is where the concept of EGR came from, like the 5 mains...the boxer needs neither.
I still ponder a real boxer without the rice. Meanwhile, you got people looking at mazda6 clubs for subaru boxer math... it aint applicable. never will be. Not even cam profiles. Study the v8, if you want outside source of boxer tips and tricks.. seriously.
