2007 Mini Cooper S: Overboost!
October 04, 2007
As you might know from reading previously published reports, the turbocharged engine in the second-generation Mini Cooper S has an "overboost" function. When the throttle is floored, increased turbo boost pressure is allowed for a brief period, and the result is more power and quicker acceleration.
When driving our long-term 2007 Cooper S, I've noticed the overboost burst of speed on numerous occasions. I've attached a pretty cool graph from Mini's press kit that shows torque and horsepower curves for the Cooper S' regular and overboosted conditions.
Actually, the chart is metric but you get the idea. Though I haven't been able to confirm this with BMW, I believe that normal maximum boost pressure is 0.8 bar (11.6 psi), rising to approximately 1 bar (~14.5 psi) in the overboost mode.
Too bad there's no boost gauge on the Cooper S so one could see overboost happen. Come to think of it, there's no coolant temperature gauge, either. Guess Mini expects owners to drive, not worry about what's going on under the hood.
Brent Romans, Senior Automotive Editor