[ever_green]

my 2.3L Acura RDX with variable geometry turbo, atkinson cycle engine and i-vtec functionality gives me 20mpg at best on the highway. The newer RDX with a 3.5L v6 get about 25mpg. but they do have a less complicated AWD system, variable cylindar management and an extra gear...so that might be the reason. But i found my turbo RDX to do better than a v6 3.5l TL (which is a 500lbs lighter 2WD sedan) in the city. If i try hard enough i can get 25mpg with my turbo RDX on a warm sunny day. I can't even get close to that with my mom's TL unless cruising on the highway. So i think V6 engines are good for highway cruising given that they have a proper overdrive gear and cylinder shutoff system. In the city it is a different story though, but the fact that honda killed it's 2.3L turbo for a 3.5L V6 is interesting.

by the way i have driven a rental sonata 2L turbo and with my driving i scored less than official MPG figures. However driving the v6 santa fe i had no trouble getting better than EPA. i find modern turbo MPG figures to be slightly optimistic. In the end it's all about how you drive it. Turbo powertrains enrich mixture heavily under load while modern NA engines tend to stay stoich.