No real limit. My dad's van has a little gauge which approximates mpg. When you accelerate hard (it's an automatic), the gauge goes down to _2_ miles per gallon. Regular driving is 18-20 mpg. And although it's a torquier engine, it still is only revving to like 3500 Rpms. So you can see how big a difference driving style makes. You might want to consider driving a little more conservatively, for your wallet's sake.