Quick question for you regarding boost. What does the Cooper S boost to as standard? Had a quick (ok, very quick) look and couldn't find much info on it. It's a pre facelift S if it makes any difference.
15psi sounds like a 15% reduced pulley. From what I hear and have seen on many cars the JCW with right aftermarket equipment and the 15% can get around 14-16psi. 17% pulleys tend to boost a little higher and can hit the traction switch off point of 18psi on a nice cold dense day if they have optimised bypass valves etc
Right, I did some more "testing" today and according to the Boost gauge it slowly creeps up to ~15psi, but it's at about 5.5-6k RPM. I'm going to go out tonight and measure the pulley if I can find it, IIRC the standard pulley is 65mm?
Not too sure what I get normal driving, the guage is down under the toggle switches so it's not something I like to look at when driving around town.
It certainly feels faster than the other S I drove, mind you It was over a year ago when I drove it. Both the same, both pre-face-lift. Friend of mine drove it on Saturday and said it's quicker than his friends which he drove earlier. I'm not too concerned if it has one or not, but it's something I can knock off the to-do list if it does.
Did a test in our Std MCS R53 yesterday and we are making ~9.5PSI boost up until last few hundred rpms where we get ~11.5psi boost. Everything is standard and the car has 104k miles on the clock but the headgasket has blown