boost problems after new turbo install

[TsiJohn333]

I just got my new sbr gt12 installed in the galant today ! i went up the road and tried to boost and only got to 11psi. Even with my EBC (greddy profec b) turned all the way up still cant boost past 11psi. it feels like somethings holding me back.

I have the dip switches set correctly for an external wastegate on my EBC. why cant i boost past 11 psi. it was working perfectly before i did my turbo swap. i was running 25psi.

I checked for boost leaks and i have the boost source going to the side of the wastegate and the top is vented. i have a valve seat ring and its not leaking. What could cause me not to boost?

I dont know if its in my head or not but it seems to drive and pull better when i run a straight line from the turbo to the wastegate.

Thanks for the help.

UPDATE - ok i so took the vacuum hose directly off the wastegate to see if i can run past 11 psi and still cant boost past 11psi. In theory, if i remove the hose i should be able to run "unlimited boost". I opened it up the other day and it has a red spring in it. ( i dont know if its the small one or big one)

 

[RvlutionMtrsprt]

Sounds like you have a lot of exhaust or charge air leaking somewhere. Worst case, the turbo is hurt.

 

[bryanwheat]

Make sure that the wastegate is closing all the way.

 

[TsiJohn333]

I am getting a relatively slow spool for what the turbo is suppose to spool up at. Maybe my valve seat ring in bad? its not leaking from the exhaust mani gasket or the turbo to mani gasket. so maybe its where the wastegate meets the flange on my o2 housing.

My wastegate if fully closing. i can here it start to open around 9-10 psi and is fully opened at 11. and at idle i cant feel any exhaust gasses coming from my dump tube at all so it must be making seal.

 

[bryanwheat]

I am getting a relatively slow spool for what the turbo is suppose to spool up at. Maybe my valve seat ring in bad? its not leaking from the exhaust mani gasket or the turbo to mani gasket. so maybe its where the wastegate meets the flange on my o2 housing.

My wastegate if fully closing. i can here it start to open around 9-10 psi and is fully opened at 11. and at idle i cant feel any exhaust gasses coming from my dump tube at all so it must be making seal.

If the wastegate isn't leaking and no boost leaks than there are few options of what could be wrong. First you could have a colapsed flex section on the downpipe, or a clogged cat. The second would be a blown turbo.

 

[RvlutionMtrsprt]

Where did this turbo come from? If you were previously making 25 psi I would doubt its the flex or cat. If there are no boost or exhaust leaks I would be suspect of the turbos condition.

 

[JusMX141]

Since SBR hasn't produced the GT12 for a while, I'm assuming this turbo is either "new" as in "old stock", or "new" as in "new to you". If it was previously-used, there's a chance it's suffered bearing damage from oil contamination which is now limiting your boost production.

 

[StarFawkes]

Is your wastegate arm adjustable? Might have to set the preload.

 

[JusMX141]

Is your wastegate arm adjustable? Might have to set the preload.

I have the dip switches set correctly for an external wastegate on my EBC.

I'm going to go ahead and say "no".

 

[StarFawkes]

Wow, completely missed that part when I read through this...

 

[TsiJohn333]

Another one of my buddies is letting me borrow his almost new tial 38mm wastegate that has a 15psi spring in it. im gonna go ahead and install it tomorrow since i know it works because we just took it off his car. i think i have a small red spring in my wastegate which i believe is a 5 psi spring.

Someone correct me if im wrong but is it true you can only boost double of what the spring is?... So say if i have a 5 psi spring that max boost is 10 psi?

Since SBR hasn't produced the GT12 for a while, I'm assuming this turbo is either "new" as in "old stock", or "new" as in "new to you". If it was previously-used, there's a chance it's suffered bearing damage from oil contamination which is now limiting your boost production.

Its almost new. i bought it off my buddy because he had no use for it. He bought it new from SBR years ago and its just been collecting dust in his garage. He ran it for only about 100 miles until he decided he wanted to rebuild his motor. He never exceeded 16 psi.

 

[JusMX141]

Wow....yeah if you only had a 5psi spring in your gate, I'd say that's the reason you're not getting any boost generated.

The spring tension on the gate is rated assuming atmospheric pressures. Depending on the turbo, there's always a certain amount of pressure between the turbine housing and engine which is also trying to force the gate open....which may be the reason you're seeing different figures between two turbos. A larger turbo with less turbine backpressure will result in the ability for the wastegate to stay shut to a higher boost level.

 

[Boostdriven]

Can you explain how you have your EBC connected to your wastegate. I ran a 38mm wastegate before with a 10 psi spring and I was able to get 28 psi of boost no problem with that same boost controller that you have.

Run a line from your compressor cover to the side port of the wastegate, then T off from that line and run another line to your boost controller solenoid, then from your solenoid to the top port of the wastegate. I have my brothers greddy profec b plummed like that and it works great.

 

[bryanwheat]

Can you explain how you have your EBC connected to your wastegate. I ran a 38mm wastegate before with a 10 psi spring and I was able to get 28 psi of boost no problem with that same boost controller that you have.

Run a line from your compressor cover to the side port of the wastegate, then T off from that line and run another line to your boost controller solenoid, then from your solenoid to the top port of the wastegate. I have my brothers greddy profec b plummed like that and it works great.

He already said that he un hooked the line to the wastegate and it wouldn't go any higher than 11 psi. This means that it is either a problem with the turbo, wastegate, or a restriction in the exhaust. With a proper working system the turbo would make the highest amount of boost that it could like this, there is no boost controller that will fix this with it hooked up right or wrong.

 

[Boostdriven]

He already said that he un hooked the line to the wastegate and it wouldn't go any higher than 11 psi. This means that it is either a problem with the turbo, wastegate, or a restriction in the exhaust. With a proper working system the turbo would make the highest amount of boost that it could like this, there is no boost controller that will fix this with it hooked up right or wrong.

I didn't tell him to unhook the line from the wastegate, I just told him how to hook up his ebc correctly, read my post again!
If indeed he has a 5 psi spring then even if he unhooks the line from the wastegate like he did he will not be able to run much more boost then double the spring pressure. Think about it, if the spring is 5 psi and your trying to run 20 psi of boost so you crank up your boost controller all your doing is closing off the air flow to the wastegate, so there is no air getting to the wastegate until 20 psi of boost which is the same thing as unplugging the hose from the wastegate. He said that he ran a line to the bottom port of the wastegate and left the top port vented, hooking it up like that will do exactly what its doing, but if you hook it up like I described before then what the boost controller does is help the spring hold the wastegate valve closed, that's how I was able to run boost 3 times the spring pressure.
Some of you guys spend to much time typing words on the keyboard and not enough time turning wrenches, do some homework before you post something that could be misleading.

 

[bryanwheat]

I didn't tell him to unhook the line from the wastegate, I just told him how to hook up his ebc correctly, read my post again!
If indeed he has a 5 psi spring then even if he unhooks the line from the wastegate like he did he will not be able to run much more boost then double the spring pressure. Think about it, if the spring is 5 psi and your trying to run 20 psi of boost so you crank up your boost controller all your doing is closing off the air flow to the wastegate, so there is no air getting to the wastegate until 20 psi of boost which is the same thing as unplugging the hose from the wastegate. He said that he ran a line to the bottom port of the wastegate and left the top port vented, hooking it up like that will do exactly what its doing, but if you hook it up like I described before then what the boost controller does is help the spring hold the wastegate valve closed, that's how I was able to run boost 3 times the spring pressure.
Some of you guys spend to much time typing words on the keyboard and not enough time turning wrenches, do some homework before you post something that could be misleading.

He said that he un hooked the hose from the wastegate, there for no pressure going to it whatsoever, so there is nothing to open the wastegate. This will make the turbo spool as high as it can until the pressure from the turbine side pushes the valve open in the wastegate. It still made 11 psi, this proves that the problem IS NOT the boost controller. Do you not understand how a boost controller works. It has a valve between the pressure source and the wastegate that keeps pressure from going to the wastegate until the target pressure is met than it opens the wastegate to control the boost. With the line un hooked the wastegate will not open, this would be the same as having the boost controller turned up all the way. The boost controller will not do anything at all if there is a problem with the wastegate , turbo, or a a restriction in the exhaust. This is how it is, you can't argue with how the system works. Also there is no need to be a dick and try to degrade someone because you don't understand what they are talking about. I promise that i have turned plenty or wrenches in my life time.

 

[Boostdriven]

He said that he un hooked the hose from the wastegate, there for no pressure going to it whatsoever, so there is nothing to open the wastegate. This will make the turbo spool as high as it can until the pressure from the turbine side pushes the valve open in the wastegate. It still made 11 psi, this proves that the problem IS NOT the boost controller. Do you not understand how a boost controller works. It has a valve between the pressure source and the wastegate that keeps pressure from going to the wastegate until the target pressure is met than it opens the wastegate to control the boost. With the line un hooked the wastegate will not open, this would be the same as having the boost controller turned up all the way. The boost controller will not do anything at all if there is a problem with the wastegate , turbo, or a a restriction in the exhaust. This is how it is, you can't argue with how the system works. Also there is no need to be a dick and try to degrade someone because you don't understand what they are talking about. I promise that i have turned plenty or wrenches in my life time.

I'm not being a dick and I know what I'm talking about. Answer a this question for yourself, why people say you can not run boost more then double the spring pressure.

Now let me help you with that. There is such thing called as exhaust pressure. When you crank up your boost controller you essentially (removing the line from the wastegate) until the boost gets up high enough to over power the spring pressure in the boost controller allowing air to go to the wastegate. With electronic boost controllers its a similar concept except its controlled electronicly. So having said that if you remove the line from the wastegate its the same as cranking up your boost controller but if you have a spring that is 5 psi then you will only get 10-11 psi of boost which is exactly what he is getting. Now whether his spring is 5 psi or not is a different story.

 

[bryanwheat]

I'm not being a dick and I know what I'm talking about. Answer a this question for yourself, why people say you can not run boost more then double the spring pressure.

Now let me help you with that. There is such thing called as exhaust pressure. When you crank up your boost controller you essentially (removing the line from the wastegate) until the boost gets up high enough to over power the spring pressure in the boost controller allowing air to go to the wastegate. With electronic boost controllers its a similar concept except its controlled electronicly. So having said that if you remove the line from the wastegate its the same as cranking up your boost controller but if you have a spring that is 5 psi then you will only get 10-11 psi of boost which is exactly what he is getting. Now whether his spring is 5 psi or not is a different story.

Look at my post, i literally said that if you remove the wastegate line than the turbo will make as much boost as it can before the wastegate blows open. The second sentence that i typed said that exactly. Also if you are using certain electronic boost controllers than you CAN run a weaker spring if you are using the top port also, because the pressure going to the top port will hold the valve in the wastegate closed similar to how a bov works. This is all assuming that the problem is the spring which could very well be. What i am getting at is that if there is a problem other than just a weak spring than a boost controller won't allow you to make any higher pressure, but if it is just a weak spring the right boost controller would in fact be able to overcome this problem.

 

[Boostdriven]

Maybe you are confusing external and internal wastegates, those are two different ball games. On external gate exhaust pressure has a direct force on the wastegate spring via valve where in the internal gate exhaust has to push against a negative leverage created by the wastegate flapper/valve arm. Try lifting 100lbs with an extended arm and you will know what I'm talking about.

 

[RvlutionMtrsprt]

Sorry, but Brian is right and you are wrong. Unplugging the wastegate is exactly how guys spike little 16g turbos over 30psi, over triple the spring pressure. When I unplug the line to the gate on my 3052 it spikes higher than a 3.5 bar map sensor can read and I'm running a .9 bar spring. Turning up a boost controller is not the same as unplugging the line. This is where your logic is flawed. Most controllers only have enough range, manipulation of the reference signal, to get you double the spring pressure. This can be overcome in some cases, to an extent, by using both ports on external gates. But even in those cases, it just isn't the same as unplugging the line.

 

[Boostdriven]

Fp3052 and gr12 have two different exhaust housings therefore will give two different exhaust pressure reading. 5 psi spring is nothing, after a good meal of beans you can fart with more force then that my friend has an Audi a4 bone stock running 10-12 psi of boost (stock) after a mild pull his manifold looks so hot its scary, it looks like its about to collapse on itself, my car don't even get that hot after I make a 3rd and 4th gear pull at 35 psi. How can that be? Maybe because that small ass housing causes so much restriction to the exhaust spiking the egts. From my understanding gt12 uses exhaust housing that's about the same as a 16g if not the same and that's pretty small considering the rest of the turbo, its possible that his exhaust pressure is higher then his boost. Take a 16g and put a 1.5 a/r housing on it and your wastegate will probably never open. Some diesel trucks don't even use the wastegate on the turbo because the air flow and boost is all calculated and the exhaust housing is matched accordingly. Maybe I'm wrong and maybe I'm not but that's not the issue at hand. He said he can hear the wastegate start to open at 9-10 psi and is fully open by 11 and its the same results with line on or off so obviously his wastegate is working, all I'm saying is to try and hook up his boost controller a little different. That is much easier then taking the turbo off the car to inspect it.

TsiJonh, try what I told you with your boost controller and if that don't we will try to help you from there.

 

[RvlutionMtrsprt]

We are in agreement that arguing won't help this guy. Apologies in advance if I'm wrong about this all together. He should try using both ports on the wastegate. Question to the op, is this wastegate setup different than you had before? Another easy test would be to replace the spring in the wastegate and see if that helps. It's something that should probably be done in the grand scheme of things anyhow, depending on how much boost you were planning on running.

 

[dsmcurse]

i also had a profect b and i hooked it up EXACTLY like how Boostdriven is exlaining. my profect b worked and was able to double my spring pressure. this was on a "turbo-header" style exhaust mannifold with a external wastegate. my profect b worked like a champ when hooked up like how boosdriven expained it. i switched to a hallman MBC because the fastest street cars in america right now are all using this boost controller. its because its the best! but back to the point. ever consider adding a boost gauge to ## exhaust mannifold ? mount your intake mannifold pressure (boost) gauge right next to ## exhuast mannifold pressure (back pressure) gauge. mount the to gauges side by side and see your boost compared to back pressure. you'll learn alot from knowing your back pressure. i know alot of people who log MAP and E-MAP both. exhaust pressure gauge is important just like boost pressure gauge.

 

[TsiJohn333]

Well I finally got this figured out. i have a large red spring in there and boost 11 psi.

I swapped my old wastegate out with a friends TO FIND OUT that a t bolt camp came loose off a coupler. i tightened that sucka down!!! i hooked up the boost source straight the the lower port on the wastegate and success!!! i boosted 15 psi with my buddies wastegate. I swapped mine back over and i can now boost normally now.

I guess i might of blown off a coupler slightly on my first pull. I did a BLT before i drove her with the new turbo.

Boostdriven, i have my EBC from the compressor to the solenoid and solenoid to the side port of the wastegate.

So your saying if i run a straight line from the compressor to the wastegate and then tee that line off to the solenoid and then solenoid to the top port of the wastegate that the pressure that is being generated will help keep my wastegate closed?

 

[RvlutionMtrsprt]

That is correct. Compressor to solenoid IN and lower port on gate, solenoid OUT to top port on gate. Same way I have my profec b hooked up.