So what concerns are there in restricting airflow through the engine compartment and around exhaust components? There's the obvious issue of the engine overheating if air is restricted too much. What if the engine stays at normal temps but the rest of the engine bay heats up. Will this have adverse effects on the battery, exhaust, catalytic converter, etc?
Over on CleanMPG, drimportracing had the idea of insulating his Metro's hood
Geo Metro Insulated Hood "how to". This seems like a good idea, but combined with a partial or full grill block and underbody tray, could you start to run into issues with not exhausting enough hot air?
I'm wondering about using drimportracing's idea to insulate my hood and the part of a future underbody tray that would be close to the exhaust pipe. Most of the engine bay would be sealed off with one inlet in a partially blocked grill and one outlet flowing around (and through) the exhaust pipe and finally exiting in the tailpipe area. Benefits would include:
* great warmup times
* less heat from a block heater lost to surroundings
* the engine should retain heat longer, thus benefitting fuel economy when running multiple short trips back to back.
Thoughts?