swajames

BMW engines - whether turbo charged or normally aspirated - are already top drawer, and BMW's engineers certainly know a thing or two about handling. That said, the cars are (and can feel) heavy and a lot of the good work from the engine and chassis engineers is undone by excess flab. The only real problem right now with BMW, particularly at the higher end, is weight. BMW would be much better advised to focus on weight saving rather than developing new powerplants as its engines are already up there with the best in their class.

BMW already has the engines it needs - all it has to do is take excess weight out of the cars. It should be power to weight and not just power that defines and differentiates the M from the regular series.

pennetta

Showing a turbo car post that is having problems doesn't mean a normally operating one has turbo lag. I have read plenty here about hesitation on BMW NA cars, many have installed Sprint Booster to help throttle response on NA cars as well. My 535 runs well and it doesn't have turbo lag. Turbo lag means that there is a delay in getting an increase in power while the turbos spin up to speed, that doesn't occur on my car. Other than smaller turbos and very light weight materials giving it less inertia, BMW designed a fuel burst between the header port and turbo so the turbo doesn't initially need engine exhaust pressure to spin the turbo. Pretty sophisticated stuff for a street car. I remember on my 300ZX Turbo I would floor the car a second or so before I wanted the power because of turbo lag.
The 535 is deceptively fast because the torque curve is flat and the car is quiet, so it doesn't feel like its accelerating as hard as it is.