It is'nt a boost spike as such, I've specifically mapped it to run 38 psi between 4500 and 6000rpm. Once over 6000 it runs a more normal 33psi.
I have mapped it this way as it gives the car a much needed midrange shove especially when changing gear and is only at the 38psi region for a short time and thus has no major problem with ACT's.
Once up to 3 figure speeds in 4th and 5th you only see the 38 psi for a brief couple of seconds when changing between 4th and 5th and then holds the 33psi.
i don't quite follow this
obviously a mid range boost peak is a desirable thing.
but if it's on air injectors programmed to give the boost curve as you describe, how is it only at 38 psi for a "brief couple of seconds" at 3 figure speeds in 4th and 5th? i have no idea how fast 500+ bhp car accelerates in those gears at those speeds, but it would seem to me that if you were flat in fifth at 4500 rpm it would take more than a "brief couple of seconds" to reach 6000 rpm?
during that time, does the ACT not rise, or is it held down by the massive airflow at those speeds?