This is my single cylinder Lego engine that does 1060rpms 60psi4.1 bars and minimum speed is 280rpms 10psi.7 bar. Here are the pix of the engine. http://s351.photobucket.com/albums/q4... Sorry for the shakiness but that's what you get with a 1 cylinder. Thanks to Nicjasno for his website that's was very helpful. Thanks for watching!