2016 Sorento EX V6
That is not how a turbo engine works lol! ("Turbo engines run rich ONLY when pushed - at higher rpms.")Wishful thinking. Let's consider facts - EPA numbers:
1. Kia Sorento 2021 7-seater 2.5L Turbo: 24 Combined, 21 City, 28 Highway
2. Kia telluride 2021 7-seater 3.8L NA: 21 Combined, 19 City, 24 Highway
Winner is clear here, no need to argue. However, since you like details, let me add to the story. Turbo engines are MORE fuel efficient at a steady highway cruise - that's why you see 4mpg increase even considering Telluride has Atkinson cycle mode. Turbo engines run rich ONLY when pushed - at higher rpms. Exactly why 2.5L Turbo engine has a huge amount of torque (almost diesel like) that allows it to never push rpms up:
1. 2.5L Turbo has 311lb.-ft. torque already at 1500rpm!
2. 3.8L NA has 262lb.-ft torque at 5200rpm.
I don't have to tell you what that means. One of them will have a freight train torque from down low and will be a much more fun to drive car than the other and all this while still being more fuel efficient and quieter ride (no need to rev rpms up). Telluride powertrain is indeed dated - it loses in every aspect.
The reason turbo engines can make so much torque down low is because they are in boost (more air and fuel is being forced into the engine making behaving like larger displacement engine)! When in boost, turbo engines have to run richer than a NA engine (due to the extra heat created by compressing air, extra fuel is required to prevent detonation vs a NA engine). While hauling a 4,000 pound SUV it will be in boost almost all of the time while accelerating (city driving). Unless someone drives very gingerly (which most people don't, especially when opting for the more performance oriented engine option), the 2.5T will not be all that efficient in real world city driving.
Revs are not the primary reason turbos engine to eat fuel, it is the boost (and then richer fuel curve need to prevent detonation than a NA engine). Also, a torquey engine like the 2.5T will never need to rev high in the first place (as it is under boost!) in normal or even fairly spirited city driving.
Yes, the Telluride gets worse EPA mpg than the new Sorento with the 2.5T in the city but turbos frequently get worse mpg in the REAL WORLD and that is why I said it will likely be no better and possibly worse in the REAL WORLD than a new Sorento if it was equipped with a 3.3 or even a 3.8. The weight savings between the new Sorento and the Telluride would also help the mpg of the 3.8 be a little better if it was put in the new Sorento than in the Telluride.
No argument from me on the highway the 2.5 would get better MPG and it has more low end torque. That being said, it will likely be less reliable. I am curious to see if the new 2.5T Sorento is quicker than the Telluride. I suspect the 2.5T will be really quick to 30 and 60 but the trap speeds may be pretty close.
Also, the 3.8 does not lose in every aspect as you indicated. It will be more refined, likely not any louder when not reved high (and even if it is, it will have a more pleasing sound than an 4 cylinder) has less moving parts and is a proven design (likely significantly more reliably), less maintenance, and similar real world mpg (except during highway driving). That being said, due to KIA's generous warranty, I would not be too reluctant to buy the 2.5T. But, when it is up there in mileage and if it needs repairs that the 3.3 or 3.8 would never have needed, that small fuel savings would not seem like it was worth it.