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> if you don't have lag or reliability problems, turbos make everything better. Smaller, faster, more fuel-efficient.

No. Mazdas SkyActiv-G do the exact opposite, because, as Mazda states it: "When you add forced induction the combustion becomes harder to control, resulting in lower efficiency". Car companies collectively research EVs and high compression Atkinson style engines, because the real world efficiency are significantly better.

But for driveability, a fast responding turbo makes sense, but a larger NA engine is better. Neither is good for efficiency. My EcoBoost Fiesta, driving 80kmph (50mph), gets around 4.0L/100km (around 59mpg), but 130kmph (80mph), is around 6.5L/100km (36mpg). This is expected due to how drag works, but the kicker is city driving. It's worse, and I can drive a Mazda 6, a significantly bigger car, with a bigger engine, in the same city, same driving, more efficiently.



Mazda has a turbocharged SkyActive-G 2.5 these days they're using on the CX-9 and it's been pretty well recieved - https://insidemazda.mazdausa.com/press-release/mazdas-turboc...

It makes a ton of torque very low down low (300 ft/lbs) which makes it very suitable to push around a midsized CUV.


According to their engineers it was a compromise because they needed a more powerful engine, and adding a turbo was simpler and faster, than design larger one in line with their SkyActive-G design philosophy.




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