I only notice this at a lower speed. Is there any reason I feel a sight drag when I take my foot off the gas in my AWD 2018 Forester? My hand brake is off. Wondering if something needs to be adjusted for smoother coasting and better mileage, or is this just an AWD thing? Not a serious problem, but I am due for a tune-up in the near future. I didn't get much of a response when I mentioned it last time I had it in.
2018 - Slight drag when coasting?
('14-'18)
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a clarification please - something often overlooked by many posters here - are you new to the car? or are you saying this is behavior that has noticeably changed recently?? This makes a big difference compared to long-time owners asking questions about things they have always noticed.
I'm trying to understand the situation. Are you talking going downhill or on level ground? On level ground, a car is supposed to slow down when you take your foot off the gas, obviously.
Clarification- I have owned the car about 2 years, no sudden difference. Level ground. This feels different than other cars I have owned when coasting. However, this is my first CVT., so it makes sense that it could just be normal behavior for this transmission. Seeing if it goes away in Neutral seems like a great idea, I will have to try that. I appreciate all the input from everyone.
I have seen the torque converter explanation Cddelta gave above from multiple sources. I experience the same engine drag feel, which is caused by the torque converter (TC). As I understand it, when gas is applied, the TC is one part of converting the energy from the engine into forward movement, and combined with the CVT, this is very efficient. The trade off comes when coasting (which is my driving style in all but freeway driving). The torque converter stays on so it can quickly resume if gas is applied, but it causes some drag and loss of energy when coasting. Overall it must be a win for efficiency as I still get great MPG. When coasting, and when the vehicle slows down to 17-20 mph, the car computer assumes you plan to stop soon and it turns off the TC, which can make it feel like the car is lurching forward suddenly.
a slight amplification to Vladder1's narrative in #8 - he/she is talking about the torque converter lockup. Torque converters are fluid couplings - an impeller and a turbine, all enclosed together in oil. There is no mechanical connection between engine in wheels, with an unlocked t.c. This is what allows you to stop while still in Drive, and has been a normal feature of nearly all automatic transmission cars since the 1940s. "Lockup" was invented in the 80s-90s, and saves gas because when locked there isn't any slippage, which happens all the time with an unlocked t.c. Subaru CVTs do have a torque converter, but because of the wide range of gear ratios the CVT can provide mechanically, the Subaru t.c. can be locked up and efficient in nearly all driving conditions. That all said, my own car's CVT t.c. (owned from new, 91,000 miles) doesn't feel draggy when coasting, to me.
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