I assume everyone with a boost gauge has it installed in the same place, i.e., in the diverter valve (the
BMW documentation calls them blow off valves). Is there any way that the spikes in boost could be just what is seen inside the intake piping between the intercooler and the throttle plate because the spring loaded diverter valves are not reacting fast enough, possibly due to the fact that we're running +6-7psi more than a stock engine?
Eugen mentioned this a few posts ago and after reading the
documentation section on Blow-off Control, and it sounds like that could be a contributing factor...
If this is true, then the engine itself isn't seeing the boost spike, but it's spiking in the intake plumbing and at the intake turbine itself which apparently is exactly what the diverter/blow-off valves are supposed to prevent.
Someone who knows about this stuff needs to chime in...