Thread: ('11+) Odd MPG Question
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Old 12-01-2012, 04:36 PM   #22
subiTWO
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Member#: 273054
Join Date: Feb 2011
Vehicle:
2012 Impreza CVT HB

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Quote:
Originally Posted by stevehnm View Post
I don't think the cvt has a locking torque converter, even in "manual" mode because it still drifts a little bit. Supposedly the final drive ratio in high gear is 2.11:1, (0.570:1 high gear and 3.70:1 diffs) and in the manual xmission it's 3.03:1 (0.738:1 high gear and 4.11:1 diffs).

http://www.concordvillecares.com/spe...13-353799.html

However, in 6th gear (about the same as loping along in Drive) at 70 mph mine is turning 2200 vs. 1980 rpm, which seems to indicate the cvt also has 4.11 diffs and that spec sheet is wrong. I don't have a service manual yet so I don't know what that says. If the gearing is correct for the 5 speed it would be turning about 2850 rpm at 70 in 5th. With the cvt in "5th" and manual it's turning about 3150 rpm at 70.
I graphed each 'gear' a year ago. Both 'first' and 'sixth' -ratios- change at higher speeds. 1st gradually shifts to a higher ratio (lower rpm) at higher speeds, and 6th downshifts.

The converter does lock-up, only if the cvt is fully up to temp, and you aren't going really slow. When slowing for a stop, you'll notice the revs drop to about 1200 below about 33 mph, and stay there, even when in manual mode in 6th. This is better than having the cvt downshift and jerk the car.

I have occasionally noticed revs jump for half a second, when I go WOT in 6th, but then it locks up tight and continues to accel.
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