subaru

[cobaltgreenz32]

my brother recently bought an 86 turbo GL...my 300zx has boost jets with a computer to up boost to around 13psi, we put a welding tip(ie boost jet) into the wastegate actuator line and the car felt sluggish. Also the factor boost indicator(yes or no on the boost) didn't turn on ever while we tested it. It was an aluminum welding tip, so it was a lil bigger hole size, but why would doing this make no boost whatsoever? Could it have needed a smaller hole in the tip? Well anyways, the turbo is out of the vehicle now due to ANOTHER blown coolant line. Thanxs in advance for any help!!!

Matt

[wroark]

Sometimes starting with the basics helps:

The point of the restrictor is to minimize the actuating force (boost pressure) on the wastegate valve (slow/prevent the point at which the valve begins cracking/opening). Given enough of an obstruction in the line (or if the line is unplugged), the actuator
diaphram will not be able to overcome the spring force trying close the valve and the valve will essentially be negated (no boost control). At this point only exhaust pressure alone would be acting on the wastegate and might even be able to budge it, if the spring is light enough.

Given this functionality, adding an obstruction or unplugging the line will not result in less boost. The "boost jet" shouldn't be causing the problem.

Possible Causes:
A weak spring in the actuator or the actuator arm being disconnected could result in the wastegate being partially or completely open, bypassing a good deal if not all of the energy meant for the turbo.

A very very bad boost leak on the pressure side (probably would hear that right away though)

Not an expert or anything but hopefully some things to think about.

[cobaltgreenz32]

well I did read somewhere on a forum that in order for a boost jet to work, some air must be bled off. My car uses boost jets "with" wastegate actuator solenoids that bleed some air back into the intake track. I think that's the problom we experienced, but I'm not sure why no boost happened.