I'm running a stock 1.9l Westy. When the engine is tuned (planning on doing it tomorrow), I unusually get about 18mpg city. I don't know what I get on the highway anymore as I haven't checked it in awhile. I have 203k on the van with a rebuild at 125k. Prior to the rebuild I was getting much less. I think it was about 12 or 14mpg. Its been awhile, so I don't recall exactly. I found tire pressure and keeping the engine tuned is the best thing to keep my mileage from dropping.