[RESOLVED] Low Boost After 16G Install !!!! Please Help

[ChrisGo]

Just got my 16g installed and took it for a spin and could only boost 10psi I have checked for boost leaks and only get them from the valve cover breather. I adjusted my MBC and no difference. I checked for exhaust leak and i do not see any carbon or any signs of a pre turbo exhaust leak. I bought the turbo used could it be bad? There is very little side to side shaft movement. The only problem i do know exist is a good size oil leak on the return line. Please help me on this i am getting discouraged

 

[hdoerr]

Is it an Ebay 16G?

 

[ChrisGo]

Is it an Ebay 16G?

Nope Mitsubishi

 

[hdoerr]

Well I can tell you that the oil leak you have sucks major *&^%$ We have the same problem but in regards to the boost issue, have you tried running manifold pressure only in order to make sure that the MBC is not broken. We used copper based RTV to seal the oil leak at the turbo and oil pan.

 

[silver bullit]

How do you have the mbc hooked up and what kind is it?

Oil return line is used or new, should get new ones casue the older they get the common it is for them to leak.

 

[97 4G63]

Do you have a 16g install kit?
where are you getting your prussure source from?
Take a look at this if you need more help email me i was having the same problem whit my 16g install
Turbo Modifications To My 1997 Eagle Talon TSi AWD

 

[blownturbotsi]

Try flipping the vacuum hoses on your MBC.

 

[el guapo]

do you still have a stock exhaust?

 

[kmoore]

do you still have a stock exhaust?

WTF What difference would that make?

 

[Mr Peepers]

WTF What difference would that make?

Exhaust can actually have a big impact on boost. For example, I couldn't build more than 14psi dropping to 10 psi with a stock muffler put back on my car(with 3"piping from the turbo). Previous 15 psi to redline.

Give us a diagram on how the MBC is hooked up, and if it's a ball and spring or bleeder type. One thing to note with ball and spring type mbc's, they won't start changing boost up until a certain point in their adjustment, and change boost very quickly after that; 2 psi or more per turn, depending on the spring.

Definitely fix the oil leak to be on the safe side.

 

[nfernotalon]

^^^ do you have the stock rims? j/k

I think you hooked up your BC backwards

 

[kmoore]

Exhaust can actually have a big impact on boost. For example, I couldn't build more than 14psi dropping to 10 psi with a stock muffler put back on my car(with 3"piping from the turbo). Previous 15 psi to redline.

But regardless you were able to increase boost from the stock psi.... whether that be the stock exhaust or not. I completely agree with you that an exhaust system can affect boost levels, but limit them completely?

 

[ChrisGo]

I will be switch around the MBC tomorrow, by the way it is a cheap OBX brand. With my return line issue will the 1g line bolt up without grinding out the holes.

Thanks for all the support

 

[Mr Peepers]

But regardless you were able to increase boost from the stock psi.... whether that be the stock exhaust or not. I completely agree with you that an exhaust system can affect boost levels, but limit them completely?

It's not very likely, I was just making the point that it's not out of the question Clogged cat etc. Irrelevant though, his profile states DP and catback

OP, how does the boost build? Does it hit 10 psi by 3-4k and stay there or slowly build to 10 psi by redline? Is it only dropping off?

 

[ChrisGo]

OP, how does the boost build? Does it hit 10 psi by 3-4k and stay there or slowly build to 10 psi by redline? Is it only dropping off?

Slowly builds by redline...

 

[98eclipsekidd08]

Slowly builds by redline...

I just went through this, swapped the plugs and got new boost cont. and now it spools up nice and quick

 

[Mr Peepers]

Does it spin freely?

Make sure the flapper is being closed all the way by the actuator, and of course that the actuator is connected to the flapper lever. If your actuator arm is adjustable it isn't an MHI 16g, and you may need to adjust it so the flapper is being held closed.

Do you have any pictures of the turbo off the car? Mainly the turbine side if you have any, I'd be looking for any cracks/erosion near the WG hole or an off-center flapper.

 

[kenamond]

Before you go changing your MBC lines around, make sure you can build WGA pressure okay: put a vaccuum line straight from the boost source to the WGA nipple and see if you boost to 10-12psi (maybe a bit less...not sure with that WGA). If that works, make sure you get the boost controller installed correctly. Then you have to properly adjust it. As was mentioned, if it's a ball/spring and it's too loose, you run WGA boost level. You need to tighten it until it starts going above the WGA boost level. Then you dial it in with small adjustments (half to full turn, do a test, repeat). If it's a bleeder type, usually all the way tight is the lowest setting (WGA boost level) and you loosen it to increase boost.

If you can post a pic, it'd be pretty easy for someone to describe how to hook it up.

And are you getting your boost signal from the j-pipe or elsewhere?

EDIT: Forgot to mention...If you're leaking from the VC breather during a BLT, that still might be a boost leak. Do the test on a fully warmed-up motor so that ring blowby is minimized. Pull the PCV valve from the back of the valve cover and do the test. If air comes out the PCV valve, replace it with an OEM one (NOT Autozone/Carquest/etc. - will NOT work). If no air comes out there but still leaks out the VC, check compression. If compression is good, your intake valve stem seals are probably leaking. Can you hold 20psi in a test? How fast did it leak down (how many seconds to drop from 20psi to 19psi)?

 

[ChrisGo]

Before you go changing your MBC lines around, make sure you can build WGA pressure okay: put a vaccuum line straight from the boost source to the WGA nipple and see if you boost to 10-12psi (maybe a bit less...not sure with that WGA). If that works, make sure you get the boost controller installed correctly. Then you have to properly adjust it. As was mentioned, if it's a ball/spring and it's too loose, you run WGA boost level. You need to tighten it until it starts going above the WGA boost level. Then you dial it in with small adjustments (half to full turn, do a test, repeat). If it's a bleeder type, usually all the way tight is the lowest setting (WGA boost level) and you loosen it to increase boost.

If you can post a pic, it'd be pretty easy for someone to describe how to hook it up.

And are you getting your boost signal from the j-pipe or elsewhere?

EDIT: Forgot to mention...If you're leaking from the VC breather during a BLT, that still might be a boost leak. Do the test on a fully warmed-up motor so that ring blowby is minimized. Pull the PCV valve from the back of the valve cover and do the test. If air comes out the PCV valve, replace it with an OEM one (NOT Autozone/Carquest/etc. - will NOT work). If no air comes out there but still leaks out the VC, check compression. If compression is good, your intake valve stem seals are probably leaking. Can you hold 20psi in a test? How fast did it leak down (how many seconds to drop from 20psi to 19psi)?

I am getting my boost source on the turbo housing.. If i do a boost leak test from the throttle body i get no leaks, but if i do i from the turbo intake i get blowbye. I am going to be honest i can not get it to hold 20psi from turbo intake, it leaks to bad from valve cover. The whole reason i replace the turbo was because of this problem and now my 16g is doing it. I just hope i did not get a bad turbo.

 

[mrallen]

hope you figure it out

 

[ChrisGo]

Well tonight i disconnected the wastegate vacuum line and it boosted to 15 psi and i let out. I don't want to damage anything. So the MBC is not working right, so i might have it in backwards. I will do minimal testing until i get the oil return leak fixed. I ordered a 90-94 oil return line from Extreme PSI it will be here Friday. I was told it will bolt right up with no modifications is this true?

 

[kenamond]

I am getting my boost source on the turbo housing.. If i do a boost leak test from the throttle body i get no leaks, but if i do i from the turbo intake i get blowbye. I am going to be honest i can not get it to hold 20psi from turbo intake, it leaks to bad from valve cover. The whole reason i replace the turbo was because of this problem and now my 16g is doing it. I just hope i did not get a bad turbo.

That's very odd that you hold boost at the TB but get VC breather leaks when testing at the turbo. There isn't any connection to the crankcase between the compressor inlet and the TB...except for the compressor seal. And you did both tests on a fully warmed-up motor?

It's good you got 15psi disabling the WGA. Just keep in mind that your MBC might still be connected correctly. If it's adjusted all the way down, you'll run around 10psi. If it's a ball/spring MBC and you hooked it up backward, you'll overboost, not underboost. If you can post a picture of the MBC and describe where the lines are going off of it, we can tell you if it's correct or not.

 

[ChrisGo]

That's very odd that you hold boost at the TB but get VC breather leaks when testing at the turbo. There isn't any connection to the crankcase between the compressor inlet and the TB...except for the compressor seal. And you did both tests on a fully warmed-up motor?

It's good you got 15psi disabling the WGA. Just keep in mind that your MBC might still be connected correctly. If it's adjusted all the way down, you'll run around 10psi. If it's a ball/spring MBC and you hooked it up backward, you'll overboost, not underboost. If you can post a picture of the MBC and describe where the lines are going off of it, we can tell you if it's correct or not.

i will post some pics tonight.. When i do the boost leak test i hear oil gurgling. As stated, this is the second turbo counting the factory one that does this. The only thing that concerns me is they both where used .

Thanks for your help


Chris

 

[kenamond]

i will post some pics tonight.. When i do the boost leak test i hear oil gurgling. As stated, this is the second turbo counting the factory one that does this. The only thing that concerns me is they both where used .

Thanks for your help


Chris

The air gurgling is normal as long as it's not a lot of it. When I do a BLT, I hear a gurgle about every second...maybe a bit faster. That's air blowing out the oil return tube into the oil pan. I'd check for leaks between the turbo and TB again. I'm betting the leak is there. You just have to find it.

 

[ChrisGo]

The air gurgling is normal as long as it's not a lot of it. When I do a BLT, I hear a gurgle about every second...maybe a bit faster. That's air blowing out the oil return tube into the oil pan. I'd check for leaks between the turbo and TB again. I'm betting the leak is there. You just have to find it.

would a leak there cause air to come out of my valve cover? I have done a BLT when it was warmed it was still there just not as bad..