R32 gtr won't boost past 9psi

[BoostisBliss]

Hey so I got a problem after blowing up my old stock turbos I cheaped out and bought another set of stock turbos and shes back running. Problem is I cant get the MBC to do anything. Seems like waste gate pressure and then that's it. I have a hallman mbc that as far as I can tell is exactly as it should be. It also has the ball in spring inside and is properly installed yet i cant get any more psi. Is removing the ball and spring a thing? There aren't any boost leaks and everything seems to be as it should. The waste gate plumbing to the MBC is really hard to see as it's under the intake manifold. Should I just run a hose directly to the waste gates that's probably my next move. Also nothing is crimped I went over everything and the action on the flapper arms is smooth. Anyone ever see an issue like this? Any info would be awesome. Thanks guys. Seems like it's running pretty rich too.

[GTSBoy]

Seriously?  I'm going to close my eyes and count to ten, then you're going to tell me how we're supposed to know what you've hooked up wrong.

[Wolfiewolfie]

MBC.

Were you using the exact same MBC with your last turbos? If so, has the adjustment knob/dial been changed at all since then? (Clockwise increases boost, counterclockwise decreases boost. Completely counterclockwise would run wastegate pressure).

If I remember the hallman MBC correctly, the nipple coming straight out of the end goes to your boost source and the one coming out at a right angle goes to your wastegate actuator. The wastegate nipple has a tiny hole on one of the flat sides of the barb that it needs in order to function, so if at any stage you took these fittings out make sure they went back in the same way.

Wastegate Actuator.

Another possibility could be the wastegate not staying closed properly, perhaps caused by the actuator arm being improperly adjusted. Did you buy this set of stock turbos brand new or second hand? If you try to move the actuator arm with your hand is it hard or does it move easily? I'm assuming the stock turbos are internally gated, otherwise ignore this one as I have no experience with external wastegate setups (yet ;P)

ECU

Are you running the standard ECU or aftermarket? Have you checked for any error codes, possibly from blowing your old turbos?

 

Without knowing your full setup that's all I can really think of... Has anything else been changed between when you had your old ones and now, even something as small as vacuum lines etc?

I'm in no way an expert, just thought I'd put my two cents in until one of the more knowledgeable members can help you out

By the way what boost were you running before?

[BoostisBliss]

MBC.
Were you using the exact same MBC with your last turbos? If so, has the adjustment knob/dial been changed at all since then? (Clockwise increases boost, counterclockwise decreases boost. Completely counterclockwise would run wastegate pressure).
If I remember the hallman MBC correctly, the nipple coming straight out of the end goes to your boost source and the one coming out at a right angle goes to your wastegate actuator. The wastegate nipple has a tiny hole on one of the flat sides of the barb that it needs in order to function, so if at any stage you took these fittings out make sure they went back in the same way.
Wastegate Actuator.
Another possibility could be the wastegate not staying closed properly, perhaps caused by the actuator arm being improperly adjusted. Did you buy this set of stock turbos brand new or second hand? If you try to move the actuator arm with your hand is it hard or does it move easily? I'm assuming the stock turbos are internally gated, otherwise ignore this one as I have no experience with external wastegate setups (yet ;P)
ECU
Are you running the standard ECU or aftermarket? Have you checked for any error codes, possibly from blowing your old turbos?
 
Without knowing your full setup that's all I can really think of... Has anything else been changed between when you had your old ones and now, even something as small as vacuum lines etc?
I'm in no way an expert, just thought I'd put my two cents in until one of the more knowledgeable members can help you out [emoji4]
By the way what boost were you running before?

Ok here's what happened I traded my evo for this car knowing it wasn't perfect drove it almost 1000 miles home and start really digging into it and find alot. Rust. CV boots tie rods random oil leaks and rest diff leaks and sorted all that. Car starts idling funny bucking like crazy after it warms up boost leak test confirms leaks in several places. Intake manifold and tbody as well as the turbosmart boost t. This was done by a r32 rb26 experienced shop but here's the strange part. They did all the gaskets on that side of the motor I get it back and the first time I put my foot down it spits out an exhaust wheel. I check the ro and see boost set to 18psi and I'm like well that's like 5 pounds higher than before why would they do that. They wouldn't take responsibility and wanted me to bring it back for new turbos. I'm broke at this point and say I've done turbos before I'll do it again. So I source a set of used OEM turbos from a shop in Texas claiming on 30k kilometers of use. They look to have been professionally cleaned. Fine. I check the shafts over seems ok swap over wastegates oil and coolant lines restud the exhaust manifold they were all mostly smoked run new coolant feeds they were seized and new cometic gaskets and hardware on everything. Get it running. When wastegates are vta the boost just keeps on climbing. So I know the actuators are staying closed when they dont see pressure. You are correct the j part of the hallman mbc goes to wastegates and the bottom is the pressure source and that's exactly as I have it. I'm going to plug the plumbing under the intake that goes around the back of the motor and run a hose directly from the MBC to the wastegates today to see if I can get her to about 12 psi until i can afford to rebuild my old set with n1 wheels. ECU is stock no codes no lights hicas works and attessa seems to be functioning I'm pleased with the car actually its come along way there was a bunch of electrical gremlins I've sorted as well but I dont think they could be related. The wastgate actuators move back and forth as they should without too much force and the arms are straight and secured tightly. Stock turbos are internally gated. You said waste gate can be adjusted? I'll look into that. I appreciate the responses alot !! I'm literally swapping the plumbing now and I'll go for a ripper see if that changes anything.

[BoostisBliss]

Seriously?  I'm going to close my eyes and count to ten, then you're going to tell me how we're supposed to know what you've hooked up wrong.

Yes. I'll try to get picks. Seems like it's all as it should be I'm just venting. As are my turbos.

[Wolfiewolfie]

Remove C clip and loosen the lock nut at the other end of the arm. Take actuator arm off the pin, adjust by winding the arm on the thread in or out. Put the arm back on pin, tighten locknut, replace C clip.

Adjustments done to the actuator should be small. Winding the arm in a few turns will shorten it and make it hold the wastegate shut with a little more force ( too short and you might have troubles with the wastegate opening).

When you say your going to run a hose directly from your MBC to wastegate, shouldn't it already be like that?

If you simply unplug the vacuum line going to the wastegate actuator it will give you unlimited boost (so go easy!). If it then gets over 9psi I'd say MBC is faulty, if it still doesn't go over 9psi I'm pretty sure you have a boost leak sonewhere

Edited February 24, 2019 by Wolfiewolfie

[Slap]

Not all actuators can be adjusted.

IF YOU ARE SO SURE THAT ITS ON CORRECT DID YOU TRY THE OPPOSITE ?

Just try it.

Pics of setup. Where it gets boost. Where it vents at the controller. Where it links to the actuator.

[BoostisBliss]

Remove C clip and loosen the lock nut at the other end of the arm. Take actuator arm off the pin, adjust by winding the arm on the thread in or out. Put the arm back on pin, tighten locknut, replace C clip.
Adjustments done to the actuator should be small. Winding the arm in a few turns will shorten it and make it hold the wastegate shut with a little more force ( too short and you might have troubles with the wastegate opening).
When you say your going to run a hose directly from your MBC to wastegate, shouldn't it already be like that?
If you simply unplug the vacuum line going to the wastegate actuator it will give you unlimited boost (so go easy!). If it then gets over 9psi I'd say MBC is faulty, if it still doesn't go over 9psi I'm pretty sure you have a boost leak sonewhere

Sorry my gma has been in the hospital haven't had a chance to mess with it much as far as I know the wastegates are not adjustable because I've had them out to swap them and the arms are fixed in place. They are OEM Garrett turbos just newer ones that have their exhaust wheels. I have tried to vent the wastegates to atmosphere like you said and they make infinite boost like you said. The thing with the hose is the stock boost control plumbing I'm using as a pressure source for the MBC. The plumbing on the gtr is a line that is on the opposite side under the intake manifold and is nearly impossible to see. It has always been used as a pressure source even before this debacle. It comes out around the back of the firewall to the other side near the rear turbo. I have always used this line for the MBC and it worked before no problem. It's just nearly impossible to see with the intake manifold on the car. It's right past the stupid place they put the oil filter. I tried running a hose directly from the WG closing this OEM vacuum line that goes around the rear of the motor as I thought perhaps there might be and obstruction or kink for some reason which really doesn't seem logical because it worked fine before and it is made of metal piping. But like I said even when bypassing the OEM pressure source piping with a rubber hose it still does the same thing. If the car is making infinite boost when the wastegates are run with open lines then I think that rules out a boost leak. But I think you may be right that the MBC might be messed up. I think my next move will be to remove the ball and spring from the MBC or then also put teflon tape around the threads for the 2 nipples to see if maybe its leaking a bit. I had an evo that had an issue with the ball getting stuck because it had become corroded, and it was making infinite boost. Once I removed the ball and spring it was fine. If that's not the issue I'll just try another MBC but it's a brand new hallman and it was holding boost on the original setup no problem so I dont know why it would be broken. I also took it apart and there is no sign of corrosion or evidence of it getting stuck. But it may be as simple as that. Again thanks for you input and I really do appreciate it more than you know. Nzz--

[BoostisBliss]

Not all actuators can be adjusted.

IF YOU ARE SO SURE THAT ITS ON CORRECT DID YOU TRY THE OPPOSITE ?

Just try it.

Pics of setup. Where it gets boost. Where it vents at the controller. Where it links to the actuator.

I have switched it all around a few times and it's either 9psi or infinite psi lol it doesn't spike or trail of or gradually make more or less. Its f**king stuck on 9 on the dot. I am really thinking this MBC is f**ked I cant imagine what else it could be unless it's the WG itself which is possible. So if just one of the wastegates was opening and the other was not functioning could that maybe cause it to only make 9psi? I will eventually be swapping in gt28r hks turbos when my funds will allow or maybe a single but for now this is what in working with. Maybe I need to swap wastegates and the MBC to get to the bottom of this .Thanks for the input I do appreciate your time.

[Slap]

Ok so you have twins?
Or single?
Each turbo needs controlling.

Here is how my bleed valve works.

Boost feed from turbo outlet niple to bleed valve entry (air bled) bleed valve to actuator. Actuator sees less boost than actual boost and keeps gate close until it sees specified modified boost signal from bleed valve.

If you are only using a restrictor type bleed valve that doesn't bleed internally (it's self) then the restricter needs to be on a line teed into the signal line so the valve exit is it's vent wich can Pass epa law if plumbed to return to the inlet air box or pod pre turbo.

Self bleed valve (good, illegal for road use)
1 line turbo to valve to actuator. (Single turbo)

Restricting bleed valve (shid , can meet emissions)
2 lines turbo to tee to actuator then line from tee to valve to air box. (Single turbo)

For twins I guess it would just need a tee from between actuators.

Do you understand?

The longer the signal line the more susceptible to boost spike

Here is my bleed valve setup

[Slap]

Seeing as you responded well I was typing lol reading that. It sounds like you need to make sure both actuators are on the signal.

[BoostisBliss]

Seeing as you responded well I was typing lol reading that. It sounds like you need to make sure both actuators are on the signal.

Ok so here's a drawing of the setup because it's hard to photo but this is exactly it. Boost source is under the intake manifold runs behind the motor back to the rear turbo. Then the line is teed between the wastegate nipples. Also not that these turbos dont have boost source nipples as they are from 1992 maybe that has nothing to do with it but I dont know. On these cars they used the intake manifold as the pressure source. Ok so I took some pictures the last pic is the pressure source do you think maybe I should try a different pressure source maybe like fuel pressure regulator? or something 155136775088815513692366041551369274607155136930140515513693289731551369353594

[BoostisBliss]

First pic is the line that goes to the intake manifold second pic is the line that goes around the back of the motor to WGs 3rd pic is where it comes out 4th pic is where the line tees into the rear turbo WG 5 pic is the front turbo line to wg and last is a drawing done by a 2nd grader that tries it all together

[Slap]

I love the drawing ahaha so good. Better than i could do its even got color.
The lines are correct. I'm not sure on the source but reckon it is right due to you getting a signal.
Sounds as if the conroler isn't venting.

Have you tried it flowing the other way through the controller?

The bearing on the spring should close the controller signal inlet under vacum I believe.

If the controller is removed and u block the outlet can you blow any air through it... try to open it whist trying if needed.... the controller valve should bleed air.
If it does it works and I'm almost stumped.
If not it's got an issue ..try the other way...still an issue pull it to bits.

If it only restricts the flow and is designed to it may need to be set up different.

Manifold line to tee continuing too anther tee then waste gates. Coming off the first tee 2nd line to controller restricting flow through as bleed to air box or inlet pre atm.

Hope you can make sense of this.
Good luck.

[Slap]

Also could have too much signal feed. Some controllers use a restricted nipple to stop the issue.

[niZmO_Man]

That drawing could be a reflection of OP's face (angry at the car) heh

[Wolfiewolfie]

@BoostisBliss if you solve this problem please let me know. Truth be told the reason I commented is because I've been having the exact same issue ever since I upgraded my R34's turbo to a gtx2863r. I've tried everything, MBC, eboost street ebc, eboost2 ebc. No matter what I can't get it to boost over 11.8psi

[BoostisBliss]

That drawing could be a reflection of OP's face (angry at the car) heh

I didn't even notice that lol!!!

[BoostisBliss]

[mention=149531]BoostisBliss[/mention] if you solve this problem please let me know. Truth be told the reason I commented is because I've been having the exact same issue ever since I upgraded my R34's turbo to a gtx2863r. I've tried everything, MBC, eboost street ebc, eboost2 ebc. No matter what I can't get it to boost over 11.8psi [emoji20]

I will keep you posted I'm gonna take the MBC apart and remove the ball and spring also try to pull pressure from somewhere else for starters it not terribly slow so it doesn't bother me too much but it's still high on my priority list now that I've got most of the other things sorted out. Let me know if you find a solution as well!!

[Wolfiewolfie]

So I fixed mine. Don't know what it was exactly, replaced wiring from ebc to solenoid, replaced all vacuum hoses and clamps, unhooked battery and pumped brake pedal to reset computer. Just took it for a drive and hit 19.2psi, popped intercooler pipe lol