car has been running fine, boost controller worked great (hallman). I recently installed a meth kit (50/50), could be a coincidence and now i cant get the boost to go down. I turned the boost constoller all the way down and its still boosting to 1.5 bar. Ive checked the lines on the MBC to the turbo and wastegate, they seem fine. It has also been pretty hot in my area, if that matters. What else should i be checking? Thanks

 

remove the controller for now, just run a line from a pressure source directly to the gate and see what boost does. Theoretically thats as low as the boost will go.

 

for now that works. could my wastegate be bad? would a line from the turbo nipple to the wastegate work for now?

 

yup just run a line from the nipple to the WG actuator. Take a close look at the heat shield in front of the actuator arm. If the rood coming out of the actuator is hitting anything or bent in anyway it could overboost.

 

I say that your boost controller was not even working properly from the begining and your tuned is most likely on wastegate spring it happened to me once, so just replace the boost controller with a working one and see if that changes anything... or remove the boost controller you have now and connect it directly to the wastegate but when you try it out but try to boost slow to see if it made any changes dont WOT it, go slow....

 

20gmr thanks im gonna give that a try. what kind psi should i see? 11 maybe? I did put an exhaust mani on a little while before and the wastegate rod was kind of a PITA to get back on, could be tweaked. colocho i couldnt make a lot of sense of what you said, im sure my BC was working. Thanks

 

if its a stock VIII turbo you should see between 10-12 psi if I remember correctly. Let me no how it goes on straight wastegate, I have an extra actuator laying around if you end up needing one pm me.

 

ok have the MBC off and just a line ran from the turbo to the wastegate and its still boosting over 1.5 bar if i let it. So i take it my WG is screwed? the rod is still connected to the flapper, but it feels kinda jammed up and the pin that holds it is missing. Can i try unbolting it and repositioning so its a bit more loose feeling? Thanks

 

You need to hook an air compressor that has a built in regulator........and hook it up to the wastegate to test it for functionality.

20psi or so through the regulated shop air should be enough to fully actuate the wastegate on the turbo.

Sounds like since you dont have the keeper pin on the rod, its bound up and not letting the wastegate open

 

OK. Since you are running a line from the WGA to the compressor discharge tube´s nipple then also pry the actuator rod off from the flapper valve´s pivot arm and go on to rotate the adjustable end of the rod to where it freely slides on and off of the pivot arm without the need of yanking on the actuator rod. This should give you WG base pressure which as someone else mentioned is between 10 and 12 PSI.

Oh, and get yourself a new cotter pin at a hardware store to secure the end of the actuator rod onto the flapper valve´s pivot arm.

 

got it figured out, the wastegate rod was jammed up and it wasnt opening. i adjusted the top part of the rod and now its working fine, and im gona put my MBC back on. Thanks