Jim in St.Louis

Does anyone know the diameter of the master cylinder in a
2007 Cayman S
2007 Boxster S
2007 Carrera S
Please share this information with me if you know or can find it.
Thanks.....

BGB Motorsports

It's pretty difficult to track down. Somewhere in the dealer PET are numbers that I found once that may indicate a difference. On each master, on the female holes for the front/rear lines, are stamped numbers everywhere. The only thing i've found that can help to identify is the number 23 on some master cylinders and 24 or 25 on others. No one has ever verified anything for us, so I just always assumed that those were the sizes used to identify the masters and the only thing I assumed they would be for is to indicate a master cyclinder that is 23mm/25.4mm or .906" or a different master that is 25mm/25.4mm, or .984". Again, this all conjecture, as Porsche doesn't do anything to help us understand what their street car parts do on our race cars.

The masters for the 1st gen. 997 and the first and 2nd gen Boxsters and Caymans are the same I believe, unless the car had PCCB brakes. The Carrera S from 2006-2008 has the bigger master that gives you the taller pedal with less pedal travel during the stint, although it is harder to modulate. From one spec racer ford driver to another, given that you like racing real race cars, get the Carrera S master. You'll like the feel. It is however a bit harder to blip the throttle, given that the brake pedal is now taller. But if you sidestep it, you can figure it out. Cheers.