[twj347]

I've got grill blocks installed on my Subaru WRX. I've also used a piece of foam to partially block the intercooler. The engine warms up a bit faster, but I'm not seeing much of an improvement in engine temperature rise with my block heater. It can get down to -40 C here, and I've got a lean-burn engine tune with reduced cold idle speed, which increases warm up time.

The hood is insulated, but the hood scoop also has vents that go directly into the engine bay on either side of the intercooler. I'm sure a lot of heat escapes from here, so I thought I'd just put an insulating blanket on top of the engine in this area.

What is a good, inexpensive material that will work? It's a boxer engine, so everything hot is down low in the engine bay. I might also use it to cover the oil filter and oil-coolant heat exchanger, which could get up to 100 C.