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Old 01-27-2018, 11:20 PM   #71 (permalink)
Calibration Engineer
Join Date: Jan 2010
Location: Canada
Posts: 86

Subie - '00 Subaru Impreza STi JDM
90 day: 22.49 mpg (US)
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Originally Posted by MetroMPG View Post
Also interesting considering the Euro & JDM versions of the car come with engine stop/start. I wonder what temp value those cars monitor to determine whether the feature is active or not.

The Euro cars also came with taller final drive gearing than everyone else gets. But the difference isn't huge. (They also have the option of a 1.0L engine in the car, but that's another story!)
I never tested the 1.0l engine so I don't know the exact specifics of that setup. Most start/stop cars have a lot more insulation on the cat and in fact some of them had to use a more expensive SS core cat that lights off considerably faster.

You can bet that a stationary cat cools much slower than one exposed to 100km/h of airflow under the vehicle. I guess they probably consider that in heavy traffic the engine will cycle off a number of times for short bouts and the cat temps can be maintained, whereas going down the highway you'll be constantly falling out of the minimum temp for operation. I don't specifically work on that part, so I can only make educated guesses.


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