Overboost problem

S

storm1513

Member
Hey all, I just installed a new Disco potato, forge boost controller and a corksport intercooler. Ran into a problem when we rolled it out for a test. The controller is turned all way down and it seems like car is over boosting the boost on the gauge just wouldn't stop it just keep climbing until it hit around 10 on the gauge and around 6k rpms then it tried to kill the engine let off and let it calm down and it did it a couple more times. What could be causing this issue? I am pretty new to this stuff so take it easy on me. It had this issue before with the old turbo which we swapped out lots of play in the shaft on it and burning oil bad.
 
another question the waste gate actuator how tight should that be. It takes a pretty hard push by hand to get it to open I am wondering if it is way to tight and not opening properly .
 
Which direction are you turning the MBC? I believe most turn the opposite direction so you think it is all the way down and it is actually maxed out. Be VERY careful with that MBC, I wouldn't even use it with a stock engine.
 
also, what kind of wastegate is on there? cuz i do believe the stock wastegate that comes on the disco is rated for 12psi. i may be wrong but you may need to switch it out and put wastegate rated for 6-8psi which u can get from ATP. but frist also check the MBC is all the way loose not tight as stated above. if its all the way tight you have it maxed out to run the max amount of boost possible.
 
the WGA will be hard to open by hand even at 6 to 8 psi so if your new turbo wastegate is actually at 12 psi, I would expect it to be extremely difficult to open by hand.
 
so the boost controller is turned all the way down tested it by turning it the other direction and well it wanted to get up to 20 or more. My car is tuned for high altitude and I am at low altitude could that be the issue? I'm getting check engine of running to lean and mass airflow to much air. The WGA is opening we know that because once it gets up to 14.5 psi it says no ( it is rated at the that) and when we turned up the boost controller it went right on by the 14.5 smooth as butter towards 20 psi. Could the boost controller at its lowest setting be causing it as well ? I have the manual forge boost controller on it ( the black plastic one).
 
no the boost controller at its lowest setting will only boost to whatever the rating is on the wastegate. and if your boosting up to 14psi i really hope your engine is built. so at least what it sounds like is you need a different wastegate with a lower spring rating. 14psi on a stock engine is a ticking time bomb even with a good tune and supporting mods.
 
Yeah you are about to pop those rods at 14psi. I would remove the MBC just to see what happens. You still need a lower psi WGA or try to adjust the one you have if it is threaded.
 
I guess the waste gate on the turbo I got from protege garage is rated at 7 psi. I got the car and it had a MBC on it, which was jacked up from coming unhooked and dragging I guess at least that is what the guy told me, so that is why it has one because I just put one back on to replace the one that got jacked up. Its tied into the line that goes to the BoV so I'm not sure how to deal with that and how to run all the lines in fact that is a little unclear. The line that comes off the Wastegate goes to the side of the MBC and the line that is coming from the intake manifold goes to the bottom of MBC but is also tied into the line going to the BoV. I hate not knowing enough and having to deal with a system that was put together right from the sounds of things in the first place. I really appreciate all the info and comments guys!
 
I'm also not even coming close to boosting when driving it at the moment until I figure out what is wrong and what to fix because ya I don't want to blow it. I don't know why but I really think the arm on the WG is overly tight and I know people tweak them to increase boost levels by making them overly tight, I really wonder if it is to tight and that is why it is just not letting it open until it gets that high.
 
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