Oranoco why the ??? just saying that i never had any running problems with my s2's and bailey dump valves and it sounds like i'm not the only one, so are you suggesting that those of us with trouble free motoring with a (DUMP VALVE) have had something wrong with our cars??? Sounds to me like those with a dump valve and the running problems are the one's with a car problem mate although in your defence i have to say mine wouldn't run right with any other apart from a bailey but i don't know why, any ideas??? who has the answer???