i cannot sustain boost over 10 psi. i peak up around 13 psi and fall to 10 almost immediatly after i hit 13 lbs. i turned up the greddy profect b and it hits a decent high but still falls off. this is well before the stock turbos should run out of air. any ideas? also, when i boost up around 5-7 psi to 9 psi i hear a schhh schhh schhh schhh and the car bucks in power while doing this, then it stops and boost all the way up. not sure what this is. ive been trying to diagnose this problem and am stumped.
also, when i first start the car when warmed up and i get into it i cant boost past 6 psi. then i slow down and get into it again and it will boost back up all the way. is this a boost controller issue?

mods are:
non seq twins
2mm atkins seals
mild street port
front mount
piping with greddy elbow
greddy s bov
fluidine rad
1680 cc mains
supra pump
aeromotive fpr
pfc tuned by BDC
clutch, lw flywheel
85mm turbo back exhaust
twin intake
pulleys
ngk 9s
greddy profect b

 

I fought the problem you describe for 6 years. The boost would never hold over 10lbs. If I turned the boost controller up, it would just spike to 15psi then drop to 10psi. I even did a non-seq. conversion.....no help. I am now in the process of converting to a single turbo.

 

yeah, i think a single is in order. at least your motor didnt go up. i guess il have to live with it until i convert. well, more reason to go single i guess.

 

Do you have a TRUE non-sequential conversion

 

Yea, the big boost spikes only happened a few times. Most of the time I set the boost to spike to 10 and level off at 7-8 psi. Not much fun but oh well, it beats a blown motor.