WTF?!?! Weird Boost Spike (sorry, long story)

[poop]

I have the following:

93 r32 GTR

blitz air pods

full Mines exhaust with front pipe

blitz DSBC spec R (set at 0.8 bar boost)

Mines ECU

All else standard

The problem I am getting is that it spikes to about 0.95-1.00 which to me, being an electronic boost controller, is just unacceptable!!! The weird thing is (to me anyway) is that the overboost only happens at full throttle and when I take my foot OFF the accelerator to change up a gear!!!

To explain it in detail:

car is in gear, apply full throttle, boost climbs up to around 0.82 at about 4000rpm (no spike), at around 6500rpm, boost drops slightly to 0.78 (all is still good) and at 8000rpm when i take my foot OFF the gas, the boost spike up to about 0.95/1.02 bar!

What could possibly be wrong? I always thought that spikes occur when the turbo kicks in? If it just spiked a bit then i wouldn't worry about it...but 0.2 of a bar...that's like 3psi....the difference between a healthy engine and a full rebuild!

I've asked my mech and he suspects that my guages are faulty but i've hooked up 2 guages to it using different points of pick up for the signal but i still get spike readings!

Another thing that he told me is that it's "theoretically" impossible. I take the boost reading from the fuel pressure regulator which is behind the throttle plates, when i take my foot off the gas, and the throttle plates close, no more boost will go in so it should read from positive boost to negative pressures instantly...hence, no spike.

This problem has really hindered me from enjoying my car. Any help you could possibly throw my way would be greatly, greatly, appreciated! Thanks!

Karl

[poop]

Only happens at full throttle. partial throttle, half throttle etc has no problems.