Originally Posted by
maquereautin
i think single turbo systems work better than two. Putting two after-market turbos on a car that wasn't designed for it is next to impossible from what i hear. singles are easier to configure and maintain i believe.
The BMW has two turbos. Each handles 3 cylinders. They are small so they spool fast. So they are acting like one rather than sequentially. I think the modern Porsche uses twin turbos - one for each half of the engine as the BMW does.
My turbo is a hybrid one that has a larger compressor section but the same turbine section as the stock one giving it higher flow. It does not produce full boost until about 2800 rpm. It's been on the engine for 70K miles, and I have over 100 track events on it. I like the way it drives. Boost is very predictable. It almost gets as much highway fuel mileage as our TL when driven normally.