Dominic,

With the 15% pulley, I was getting about 14.5 - 15 psi of boost, so I clearly knew something was wrong when the 19% delivered the same boost . The gauge was not at fault because boost pressure was measured with two additional gauges. BTW, I was at AMVIV2; perhaps you saw my car with its airplane-like cockpit .

Cheers,

 

I think I might remember a car like that!

 

I assumed that anyone who would go to the expense and effort to fit auxiliary gauges might have a clue about what the normal values are. These values can be found in a number of places, both online and in manuals.

Of course, some people need to be spoon fed...