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Discussion Starter · #1 · (Edited)
There has been a lot of discussion about replacing the existing naturally aspirated Subaru engines (2.0 liter 152 hp and 2.5 liter 182 hp) in order to improve fuel economy. Tied in with that discussion is the addition of Toyota hybrid technology (regular or plug-in) to further increase mpg. Most rumours involve replacing the 2.0 liter naturally aspirated with a 1.5 liter turbocharged, and replacing the 2.5 liter naturally aspirated with the existing Levorg 1.8 liter turbocharged (possibly with an optional hybrid motor).

Consumer concerns are about upfront vehicle cost increasing, increased maintenance cost of a turbo, and possibly shorter length of usable life.

If we look at a table of EPA mpg calculations for automatic AWD vehicles we see that Subaru is one of the top performers right now in this class compared to smaller turbocharged engines from other manufacturers (see table).
Variants of Subaru's 2.4 liter engine in the sports cars (WRX and BRZ), the higher trims of the Legacy and Outback , plus the Ascent don't seem to have any issues, but very few of them have passed 100,000 miles.

The Solterra is not directly tied into this issue, but if it sells like gangbusters perhaps Subaru will get an improved CAFE and satisfy the ZEV states so that it might decide to stay with current naturally aspirated engines for the gasoline engines.
 

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Honestly, the issue is city/urban and short duration trips where the engine can't come up to temperature. Have to say, I would be happy with my Outback if it had a battery or something else for city/urban driving. I am willing to accept the ~30 mpg it will hold on highways, this is a wagon/SUV after all, filled with my stuff in the cargo hold. If they could find a way to make the cars get ~30+ in the city as well, that would be wonderful. You'll instantly "double" the practical economy across your fleet for urban driving.

There's also the Atkinson cycle trick to gain extra economy as well.
 

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Discussion Starter · #3 · (Edited)
It looks like Subaru is going ahead with a 1.5 liter and 1.9 liter turbocharged engine, but it is unclear if they will come to the United States. As you can see, the fuel economy of Subaru entry level sedans has not improved much in 38 years, but the horsepower went up from 68 hp to 152 hp
  • 1984 Subaru Sedan with 1.6L, 4 cyl, Manual 4-spd | Highway MPG:33
  • 2022 Subaru Impreza 4-Door with 2.0L, 4 cyl, Manual 5-spd | Highway MPG:31
I am worried about a new 1.5 liter turbocharged engine screwing up this reliable vehicle. However, it looks like Subaru executives will press ahead even before the Solterra goes on sale.
 

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I am worried about a new 1.5 liter turbocharged engine screwing up this reliable vehicle.
The industry in general is moving toward smaller displacement, turbocharged ICE engines as they compliment hybrid nicely while potentially keeping fuel consumption lower. There is already a lot of experience with turbocharging in the industry. I really don't feel there is a need to worry about it, honestly.

And it's a non-factor relative to Solterra.
 

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Discussion Starter · #5 · (Edited)
Some people worry about this trend very vocally.

I know that Subaru built their first turbocharged engine in 1983 and it was for a 1.8 liter engine.
1984 Subaru Sedan 4WD 1.8 L, 4 cyl, Automatic 3-spd, Turbo
1984 Subaru Wagon 4WD 1.8 L, 4 cyl, Automatic 3-spd, Turbo
1984 Subaru Brat 4WD 1.8 L, 4 cyl, Automatic 3-spd, Turbo

So it is not like I don't realize that they have experience building turbo engines. It just adds some complication which doesn't seem necessary.


In an earlier post said:
The Solterra is not directly tied into this issue, but if it sells like gangbusters perhaps Subaru will get an improved CAFE and satisfy the ZEV states so that it might decide to stay with current naturally aspirated engines for the gasoline engines.
I think it is tied to the MSRP they go with for the Solterra.

When Subaru started selling the BRZ they issued a statement that said they expected to sell 500 per month. For the first 60 months they averaged 518 sales. When they issued the Crosstrek hybrid they priced it so high, and only made it available in limited states, so that the sales appear to be minimal. They have not issued a statement that I am aware of as to how many Solterra's they intend to sell, but obviously if it is priced starting at $45,000 that will limit sales. Presumably most people on this forum are hoping the Solterra is more than a boutique compliance vehicle.
 
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