BMW: heat is goot!

[101lifts2]

Originally Posted by goof2

I agree. I don't care about admiring an engine, but I do care about maintaining it. I keep vehicles for a long time, a lot longer than BMW's "included" maintenance period. I'm not paying a dealer $300 in labor to remove, and later replace, a ton of crap around the engine before they even start working on the car.

As for the earlier question about why no one has done this before I can think of a few reasons. A warm engine is best, but once it gets warm a lot of effort goes in to keeping it from getting hot.

One thing that helps is airflow around the engine. Wrapping the engine in heat blankets kind of kills that option. Now you need a larger radiator (weight), more coolant (weight), and a larger cooling fan that needs to run more (more draw on the alternator). Lugging around that extra weight, plus the additional weight of the system, as well as heavier draw from the alternator all contribute to more fuel consumption.

That extra fuel consumption is not particularly significant, but it is always happening. The fuel savings of this system are not particularly significant either, it only occurs for the first 20 minutes, and its effect is diminishing over that time. This system may result in a net benefit, but it will be smaller than even the minuscule numbers claimed in the article. I would trade that benefit for slightly easier maintenance in a heartbeat.

The whole point of the blanket is to reduce toxic emisison output, which during a drive cycle, is mostly (80%) from the warmup period. The "added" fuel economy is actually pretty negligable, but you have to spin something if you want more coin, right?