Quote: Adding the turbo alone is going to decrease fuel economy, between the weight added to the vehicle and the increased pumping losses with the turbo in the exhaust stream.
All one has to do is compare factory engines that are mostly the same aside from turbo setups.
Chrysler had both in 1989- An N/A 2.5 and a turbocharged 2.5.
For all intents and purposes the main differences between the two is a touch more static compression with the N/A motor, the N/A motor has a cam with slightly more overlap. Even though the turbomotor has a far superior intake setup (MPI vs craptastic TBI) the N/A motor was well noted for its better MPG.
21-36 mpg for the N/A motor, 18-26 mpg for the turbo. These numbers are from the Federal MPG website with the same vehicle with manual transmissions.
You are not going to get better mpg slapping on a turbo without reduction of displacement, period.
