Standard boost is 13.2psi, or 900mBar, but in the std setup the actuator is set to open at 8psi.
13.2 is attained by a pulsating solenoid valve, AKA the amal valve. It pulses at a constant frequency of 12 Hertz, so <time open>+<Time closed> equals <constant> but it varies time open and closed to make the adjustment. It basically acts as an electronic bleed valve....boost controller stylee. When you are in 1st gear (2wd only) or engine temp is below 50 centigrade it limits boost to actuator pressure, ie 8psi, otherwise it changes its pulse profile to bleed away pressure and allows 13.2psi.
On top of all that, it also controls pre throttle butterfly boost pressure according to how much throttle you have on. Its a brilliant innovation, half throttle=half boost, instead of a setup like my old ph1 with no amal valve which hit over a bar of boost at 1/3 throttle. Great for fuel saving and cruising, prolongs the life of the turbo as it doesnt work as hard as well.
All this though, is assuming its working correctly. Problems begin when its not, from boosting low (8psi) to massive overboost (BOOM!). The overboost problem is dangerous but Renault saw fit to add an overboost protection system. It cuts in around 18psi and it breaks a circuit and turns your engine off. Again assuming its working, and hasnt been f**ked with by some boost hungry little scally. DO NOT REMOVE IT. Take the time to adjust and reset it to the required level.
If you do get problems with boost the first thing I suggest is eliminate the electronics, which in cliffs case has proved that the mechanicals are working correctly, so the fault lies with the electronics. Replacing the valve should prove fruitful, if not there is a possible wiring problem as earthing one of the amal valve wires results in it spazzing out and jamming open giving up to about 21psi.
Anyway, enough crap for now, i'm off to eat another folder of Renault manuals :lol:
