I just purchased a 87 buick grand national and was wondering how much boost do they run stock because this one seems to peg the stock gauge at wot. What vacume lines should i check at the waste gate for damage,if it is too much boost.
Check all vac lines, but the one from the soilnoid (on top the the passanger valve cover) goes out to a "Y" to the housing and the wastegate. It is famous for leaking and blowing off. If you replace it check the openings in the new "y" fitting. Do a search here or on other sites to get the specs.
The stock guage for the boost is most likely incorrect as they were not very accurate.
I'm not sure on the factory setting on boost but no more than 15 and more like 13 I would guess.
What's it plugged with? There was a little foam filter there from the factory, but many of them have fallen off or something. Nothing should go there, unless you still have the little filter on there. It won't hurt anything.
I'm just wondering if it being completely plugged with something will hurt. Most just vent to the air. Steve??
There should be one line attached to the solenoid only. The solenoid acts as a bleeder and must have the other side open or it cannot function properly.
The line attached to the solenoid (does not make any difference which port on the solenoid is used) goes to the "tee" Or "Y" that runs to the turbo housing and the wastegate actuator. Note that there is a restrictor in one leg of this "y". The straight leg of this "Y" goes to the turbo housing. The branched off leg goes to the actuator.
If the hose coming from this "y" to the wastegate solenoid on the valve cover is removed from the solenoid and plugged up, the boost will be controlled by the spring tension in the actuator rather than the cars ecm.
The way, I described it is the way it should be hooked.
Having said that, we don't have a clue what your car is doing because it does not have a proper boost gauge on it. Therefore we cannot tell if the wastegate solenoid is working correctly or what. And, we don't know if the prior owner had a clue about what he was doing or if he had some reason for defeating the solenoid.
I suspect that the boost is currently being set with an adjustable wastegate rod.
Before you do anything, you need to put a boost gauge on it. I kinda like the Autometer 2 1/16" Phantom series that goes from 30" of vacuum to 30# of boost.
Put something on it so we don't blow any head gaskets.