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Old 02-09-2012, 06:57 AM
KeithS KeithS is offline
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Location: Central NJ
 
Join Date: Dec 2001
Posts: 1,641
Mein Auto: '11 335d, '00 540iT
Quote:
Originally Posted by TDIwyse View Post
Here's the last two days morning commutes showing engine temps and trip mpg's. Interesting to me to see how horrible fuel efficiency is on a cold engine and how directly related it is to engine temp.
Very interesting indeed. The graphs show what I've been suspecting for a while. That MPG really is in the toilet at cold engine temperatures. Seems MUCH more so than on gasoline engines. How just driving for one mile with a cold started engine can take more than 1 MPG off the displayed tank MPG average, with 450 miles on it.

We have 2 cars, the 335d and a '00 540iT. We're driving the d almost all the time except when we need the cargo room or weather is real bad (the iT has real snow tires). My wife has a very short commute, about 5 miles. It may make more sense to have her take the 540 to work as it looks like it may actually get better MPG for these short trips.

Not that it matters my average MPG display runs about 4% pessimistic compared to manually calculated values.

Last edited by KeithS; 02-09-2012 at 06:59 AM.
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