Turbo Boost Creep Creeping T25 14B 16G [Merged]

[dsmdragon]

A 1.5" pipe will not mater as much unless your runing it, say longer then 4ft. Check your porting job to the wastegate housing and make sure the wastegate is staying open and isn't closing half way or something

 

[Kyle97turbo]

I went off the vfaq article for my porting. As for the wastegate opening, I already tested that and the actuator is moving fine. I can hear the wastegate opening around 12 psi and it holds there for a couple seconds then creeps.

 

[winterftbl]

What kind of boost controller do you have? I know that with my big 16g and dump it never creeped, stayed right at 12. But now that my mbc ####ed up it would creep like crazy. What is your mbc set at?

 

[TurboAnything]

Its is a simple as flow through the wastegate passage. You need to take it all back apart and port the hole for your wastegate. Try to port the inlet of the turbine housing so it diverts more of the gas out. EvoIII's are hard to get perfect but it can be done.

 

[Kyle97turbo]

What kind of boost controller do you have? I know that with my big 16g and dump it never creeped, stayed right at 12. But now that my mbc ####ed up it would creep like crazy. What is your mbc set at?

I have the sbr mbc and its backed all the way out just so the bolt is touching the spring. I think the next thing in order is gonna be a hallman pro mbc.

 

[Kyle97turbo]

Its is a simple as flow through the wastegate passage. You need to take it all back apart and port the hole for your wastegate. Try to port the inlet of the turbine housing so it diverts more of the gas out. EvoIII's are hard to get perfect but it can be done.

I ported the living hell out of that thing. I was getting scared the walls of the turbine housing were going to crack.

 

[Kyle97turbo]

K so I've given up any hope of controlling boost with my internal wastegate and now I'm going to put an external on an o2 housing. My one last question is how important is it to completely port out the wastegate hole on the turbo?? I will be using a tial 38mm.

 

[tsi8820]

it is very important. if your gonna use an external you need that wg hole to be big. the more of the excess gasses you can get out the less likely you are to get creep

 

[nfernotalon]

Ok guys an update on this thread, I unhooked the arm from the actuator and the flapper moves fine its not caught on something or stuck, I also moved the spring with pliers and moves fine, what else could it be?? Also I dont see anything wrong with the vacuum lines on the MBC

 

[nfernotalon]

Anyone...

 

[rrussell]

While the O2 housing is off try testing the MBC by using a spray gun regulator w/gauge.

Take your gun regulator w/gauge and hook it up to the pressure side of the MBC. Start off with the gun regulator turned off(no flow) Then turn the gun regulator up to whatever psi your running.

As you start reach your set psi watch the waste-gate flap and see if its opening or not.

Then do the same test without the MBC by bi-passing it.

You can find gun regulator's for around $28.00

 

[kenamond]

If your WG flapper is not turning freely, you need to fix that. To make sure, you disconnected the WGA actuator arm from the lever on the turbine housing and then tried turning the lever by hand, right? If not, try that. The lever should turn freely. If it won't turn freely, drop the turbo and figure out what's wrong. I'm not sure if you could tell much if you just dropped the O2 housing, but I guess you could try that first.

The WG flapper is literally what limits your boost, and if it isn't opening, you have no boost control.

If the lever turns freely, you can do a number of things that others have suggested that you haven't tried yet. Test the WGA to see if it opens the WG at around 10-12psi. If that doesn't work, the WGA is likely shot. If that works, try running a vaccuum line straight from the compressor outlet to the WGA. That should get you about 10psi boost. If that doesn't work, disconnect the WGA actuator arm from the WG lever and do a pull like that. If you boost past a few psi, it's likely boost creep.

 

[nfernotalon]

Does anyone know how much the WG actuators are and where to get one?

 

[kenamond]

Does anyone know how much the WG actuators are and where to get one?

Did you test the WGA (with a pressure tester)?

 

[nfernotalon]

I will test the actuator tomorrow, too cold right now.. I will update on it as soon as i can. thanks

 

[kenamond]

Good. May save yourself some cash by finding out what's wrong first.

Just keep in mind that the compressor outlet provides a boost signal. This goes through a vaccuum line to the MBC. Then another line goes to the WGA. The actuator arm goes from the WGA to the lever on the turbine housing. The lever turns the WG flapper and releases backpressure upwind of the turbine wheel, thus limiting how much exhaust flow it gets and therefore how much boost the compressor wheel (on the other end of the shaft) will generate as a result. Something in that chain of parts isn't doing what it's supposed to. Could be a cracked/leaking vaccuum line between the MBC and the compressor outlet or WGA. Could be the MBC isn't set right or is faulty. Could be the WGA is bad. Could be the actuator arm is binding on something (heat shield). Could be the WG flapper isn't opening enough to limit boost (boost creep). Just eliminate potential problems methodically.

 

[nfernotalon]

Ok so I blew air in the actuator and it moves the arm like it should, I also checked the vacuum hoses in the MBC and found no holes or anything.. I have a video but dont know how to load it on to here from my digital camara

 

[91LaSerTurBo3]

im not sure whether or not this is technically boost creep or not. but, my car has no boost controller, and the BCS has been disconnected, as well it has a 3" turboback exhaust, so although it should be running at its stock boost setting or 1-2psi higher, its getting up to 18-19psi, and im wondering if i put a MBC in my car, and set it to something like 15 psi, will i continue to get boost creep if this is boost creep, or will the car then begin to have boost creep, or will this generaly solve the problem of boost creep. Thanks any comments and help is appreciated

 

[dsmzoom]

What do you mean your BCS is disconnected? As in the vaccum hoses or the harness?Your BCS needs to be connected especially if your not running an MBC, the harness always need to be connected running a MBC or not because it throws a CEL. This will cause your boost spikes because theres nothing telling when your wastegate to open.

 

[jc 340]

If you are running a line from your boost source directly to your wastegate and creeping up to 18-19 psi, then it is likley that a boost controller will not solve this problem. You will probably have to port the turbine housing inlet, wastegate, and 02 housing to solve this problem.

 

[91LaSerTurBo3]

ive been told from the previous owner that that bcs is connected to the ECM but is no longer connected to the WasteGate

 

[MrBoxx]

What do you mean your BCS is disconnected? As in the vaccum hoses or the harness?Your BCS needs to be connected especially if your not running an MBC, the harness always need to be connected running a MBC or not because it throws a CEL.

1g's don't throw CEL's for disconnected BCS harnesses. Only 2g's, and even then, it's hit-or-miss.

As jc 430 said, run a vacuum line straight from the turbo outlet/j-pipe straight to the wastegate actuator. If this still causes spike or creep, then you need to do some porting, especially on the turbine inlet before the wastegate passage, to ease the flow towards the wastegate.

 

[1993gsxtalon]

I was running similar to the same setup without a stock boost control solenoid and no vaccum hoses coming off my throttle body. What fixed my prob is just a mild port on the o2 housing because i already have a down pipe. Mine use to creep to 25psi from 10psi ! and after the mild port i only creep to 15psi.

 

[tqmx1]

Check your waste gate controller. It sounds like there might be a hole in the diaphram locking the waste gate closed.

 

[kenamond]

Connect a vaccuum line straight from the compressor outlet nipple to the WGA nipple and see what boost you top out at. If it's 10-12psi, the MBC is the problem. If not, disconnect the WGA actuator arm from the lever on the housing and do a pull that way and see what the boost tops out at. If it goes past a few psi, it sounds like boost creep. But you won't know until you do the tests.