Over Boosting? Need some help guys

[asshanson]

30psi is a ton of boost creep, wow.
Did you try hooking the actuator directly to the intake manifold vacuum source?

[1990GSX]

Edit: I missed this post:

so i removed the arm and took it for a drive, at about 4-5k i was seeing about 20 pounds of boost and at about 6/6.5 almost 30 pounds of boost. So if i am thinking right this means i found the problem, and that is that my waste gate is bad? So start shopping for a big 16g Waste gate actuator?

Do this:

30psi is a ton of boost creep, wow.
Did you try hooking the actuator directly to the intake manifold vacuum source?

[talonsway]

Boost source will be going to the intake next. with that flapper open like i had it. Shouldnt i have not been able to boost at all?

[1990GSX]

Boost source will be going to the intake next. with that flapper open like i had it. Shouldnt i have not been able to boost at all?

It should have been as low as you can physically go if you were sure the arm was removed and flapper stuck actuated to have the wastegate channel open. That is why halon was saying if you still were getting creep with the wastegate fully open changing the actuator will not help cure your problem. You will need to enlarge the wastegate so you can vent off more air.

The steps people want you to take are as follows:

1. Open wastegate fully check air flow by disconnecting rod/actuating flapper. Once you confirm you can flow enough air to avoid the boost raising above your target point then go to step 2. If you cannot flow enough air you know this is your problem.

2. Hook actuator back up to compressor source without mbc installed. The boost should build to the point in which the spring holding the wastegate flapper is overcome by the boost pressure. The wastegate will then open and start diverting exhaust gases away from the turbo. If this works correctly and only creeps to a stable amount like the 20-21 psi shane said then you know this is going to be your boost level unless you set the mbc higher. You can then go to step 4. If your still getting a problem after this you can check the following: actuator arm stuck/not working bad actuator or go on to step 3.

3. Hook actuator up to inlet source. If this fixes your problem then it was something with the source. Go on to step 4.

4. Install mbc. Set boost level. If you set it below the 20-21 psi (or whatever psi the wastegate actuator/flapper is allowing to flow) its likely going to creep back up to that anyway. If you set it above it should build to the desired level and hold. If your just spooling building boost as before then you know its your mbc.

[Shane@DBPerformance]

so i removed the arm and took it for a drive, at about 4-5k i was seeing about 20 pounds of boost and at about 6/6.5 almost 30 pounds of boost. So if i am thinking right this means i found the problem, and that is that my waste gate is bad? So start shopping for a big 16g Waste gate actuator?

If I am reading this right and the arm was removed to allow the flapper to open all the way right away, then you have bad boost creep. The fix would be a larger flapper and porting or an external wastegate. Another option is to choke the exhaust or intake system so that the turbo has a hard time making boost, which obviously isn't the best option for power.


well I wanted to hold 15 maybe 20 pounds. So if I could get it to hold around there I would be happy. Might just start saving for a external waste gate set up, just drive it like it is because I can not figure out why this is happen. My friends DSM with his 16g and he only boost like 12 and it holds perfect

Being able to hold 12psi fine with a 16G on a DSM is actually weird and not how they normally act. And what his car is doing does not matter and is not going to fix what yours is doing.

[goodhart]

How a 16g could build 30psi with an open wategate flap blows my mind, unless either 1) your flap is welded shut and you don't know, or 2) you are running no exhaust and are giving it more air than any 16g in history. Most barely get over 30 with a basically forced shut flapper.

[Shane@DBPerformance]

Bad boost gauge?

[talonsway]

If I am reading this right and the arm was removed to allow the flapper to open all the way right away, then you have bad boost creep. The fix would be a larger flapper and porting or an external wastegate. Another option is to choke the exhaust or intake system so that the turbo has a hard time making boost, which obviously isn't the best option for power.

Yes you are right i removed the arm, and gave her throttle and at about 6k had about 25 pounds of boost. Im debating on going with a larger flapper, but would like to go with a external wastage set up. But don't really have the money for that. For a proper external waste gate would you go off the manifold or the o2 housing? And i would need to weld that flapper hole shut.

[turbotalon1g]

Manifold at the collector or O2 housing.
I have an O2 housing built for ext. WG if you ready to buy.

[talonsway]

I think i would want to go with a ext. WG at the collector of the manifold not the o2 housing? Ive read that you would need to do porting every time you change your turbo if i went with a ext. WG off the o2 housing. And that people recommend going with a ext. WG off the manifold.