I have a question about boost pressures, since fitting a full twin pass front mount intercooler the boost pressures are vastly different in behaviour to how they where when the charge cooler was fitted. What happens is when accelerating through 2nd the boost pressure peaks at 20 p.s.i and drops gradually as the revs increase to around 14 p.s.i then in 3rd the boost pressures will again peak at 20 p.s.i then drop off to around 16 p.s.i as the revs increase then when in 4th and 5th the boost peaks at 20 p.s.i and drops and holds 18 p.s.i. not dropping off like it does in the lower gears. I thought at first the actuator I had may have been weak so I have replaced the actuator with a Garrett -31 and just fitted a brand new amal valve with no effect to the boost pressures. I have checked the boost hoses and hoses from the compressor wheel to the actuator/amal valve and they are all secure with no leaks. Is this boost drop in the lower gears due to the increase in area that the turbo has to fill since fitting the intercooler, as it didn't do it with the charge cooler fitted, and would it be worth me ditching the amal valve and fitting a proper electronic boost controller? If so which one should I go for?

Any advice would be greatly appreciated,

Cheers in advance

Andy