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2017 Outback 2.5i Premium; 2019 Outback 2.5i Premium
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Discussion Starter · #1 ·
Hi,

When we took possession of our new 2017 Outback 2.5i Premium (CVT), the highway speed at 2000 RPMs consistently was around 75 MPH. Now, approximately 6 months and 6200 miles later, an engine RPM of 2000 only results in around 70 MPH, and to achieve 75 MPH, the RPM needs to be ~ 2200. Has anyone else noticed such a drop after the 'break-in' period?

I'm not sure when this change occurred, but as far as I can tell, the driving conditions should all be more or less the same as when observed some time earlier (A/C off; same tire pressures (albeit almost 2mm less tread on all 4 tires :frown2:), flat stretch of highway, same engine oil level, 'calm' weather, etc.). Interestingly, the green MPG indicator still shows up as maximum at around 2000 RPM, even though the speed is now 70 MPH.

The reason for asking is that on two or three occasions now, I've also felt the car 'lurch' slightly (for maybe 1-2 seconds) when slowly accelerating away at low speeds (maybe around 25-30 MPH?) -- and by 'lurching', I mean that it's as though the CVT briefly can't make up its mind on what it wants to do (e.g., which 'gear' it should be in (ignoring the fact that it's a CVT)). This has only occurred when the car is relatively cold from startup. I'm not the daily driver of the car, and so perhaps I'm not giving enough gas 'firmly' ... or, I was wondering, maybe this is somehow related with the drop in highway cruising speed? My wife hasn't complained, but I'm not sure if she'd notice such things in general ...

I'll continue to monitor closely, but was wondering if others had similar experiences, or if it's just me being overly concerned.

Many thanks!
 

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Premium Member
2016 Outback Premium 2.5 CVT w/EyeSight+SRVD
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7,663 Posts
When we took possession of our new 2017 Outback 2.5i Premium (CVT), the highway speed at 2000 RPMs consistently was around 75 MPH. Now, approximately 6 months and 6200 miles later, an engine RPM of 2000 only results in around 70 MPH, and to achieve 75 MPH, the RPM needs to be ~ 2200.
If you do the math, rpm for the 2.5 engine at 75 mph should fall somewhere in the range of 2150 rpm (CVT ratio = 0.570 ... 1718 engine revs/mile) to 2330 rpm (CVT ratio = 0.618 ... 1862 engine revs/mile). This assumes Premium trim and the OE 225/65R17 tires ... 733 tire revs/mile.

... wondering ... if it's just me being overly concerned.
Yes.
 

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Twilight Blue 2015 3.6R with Eyesight
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5,023 Posts
^
^
^
What he said...
As for the lurching, that's the torque converter locking, very normal.
 
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2018 3.6R Limited
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552 Posts
CVT adapts to driver's habits, so it is not possible to have apples to apples comparison between brand new car and one you've driven for year(s).
Disconnect the battery, and you'll see what I mean - it will reset CVT.
 

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2017 Outback 2.5i Premium; 2019 Outback 2.5i Premium
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Discussion Starter · #5 ·
Many thanks @ammcinnis, @KentuckyOutback, @byebye6cyl! Out of curiosity, where did you get the source of the gear ratios -- or is another RTFM thing ...?

I've only observed the 'lurching' when the engine (and presumably transmission) is relatively cold thus far -- it was NOT observed when the vehicle was 'brand new', though (and perhaps is due to CVT 'learning'?) I don't know how to properly describe it, but in a gear-like analogy, it's as though the transmission shifts into a higher, then lower, then back to the higher gear again (with maybe one or more additional cycles of lower and then back to higher gear occurring) -- a type of 'chattering' phenomenon all within a short 1-2 second timespan, before finally settling down. It does all of this so much that the car'jerks' a bit. I guess it's another thing to get used to with the CVT (or changes to the heaviness of my right foot are needed)?

Again, many thanks for all of your insightful feedback!
 

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2016 Outback Premium 2.5 CVT w/EyeSight+SRVD
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... where did you get the source of the gear ratios ...?
The 0.570 ratio is a mechanical limit in the G2 CVT, per the Subaru Factory Service Manual. The 0.618 is the "6th gear" ratio commanded by the CVT controller in manual mode, per Subaru technician training materials and other Subaru documents that I can't locate right now. The tire revs per mile (i.e. rolling radius) values are from the tire manufacturers and/or TireRack.com technical data.

G2 CVT "gear" ratios (2.5 engine only)
Range (AUTO mode): 3.581-0.570
Reverse: 3.667
MANUAL mode:
"1st gear": ~3.5
"2nd gear": ~2.262
"3rd gear": ~1.658
"4th gear": ~1.208
"5th gear": ~0.885
"6th gear": ~0.618

G1 CVT "gear" ratios (3.6 engine only)
Range (AUTO mode): 2.37-0.39 (FSM: 3.105-0.482 ???)
Reverse: 2.09 (FSM: 3.018 ???)
MANUAL mode:
"1st gear": ~2.18
"2nd gear": ~1.45
"3rd gear": ~1.03
"4th gear": ~0.77
"5th gear": ~0.58
"6th gear": ~0.40
(N.B. There is a substantial discrepancy for the G1 CVT between the ratios listed in the 2015 FSM and in Subaru technician training materials.)
 
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6 months ago it was the middle of winter. Now it's the middle of summer.

Air temps and densities can make a difference in HP production and drag. The result could affect a given RPM/MPH relationship with a CVT.

I've never paid attention that closely, it will be interesting to see if your numbers change again in another 6 months.
 
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