t25 too much boost

[2gGst98]

ok so I removed the bcs restrictor on my gst a few weeks ago, and began hitting about 20 pst then drops at higher rpm's. I know this happens to a good amount of people, how did you guys fix it?

I got a MBC over the weekend and I no its hooked up right. I have no leaks besides a tiny one in the TB. Why am I spiking up at 20 then comming down to 12 at about 4.5k - 5k.

I have done alot of reading the past 3 days and I cant find anyone giving a cure to this. So if someone can help me out by either telling me or showing me a link I would appreciate it.

 

[knochgoon24]

Are you sure it's hooked up right?

A T25 won't last long when abused with boost spikes like that. Mine let loose after a (long) day at the drag strip at 17psi.

 

[jtmcinder]

Why does it come down? Because a T25 can't flow very much. Why does start up high? Odds are, because you have the MBC set incorrectly.

 

[2gTurBoD]

Are you sure it's hooked up right?

A T25 won't last long when abused with boost spikes like that. Mine let loose after a (long) day at the drag strip at 17psi.

I to thought for sure mine was hooked up right until I hit 25 psi when i only wanted 17psi. I would double check it.

 

[2gGst98]

its a hollman MBC It is hooked up right. Would a bad t25 spike? I also have the controller all the way down. And unless the pic it gives is supposed to be hooked up oppisitely then its correct. I can take a pik if you want.

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ok so the vac. line comming from the front goes to compressor housing, bottom vac. line goes to waste gate

Knob is turned all the way down.

I do appreciate all the quick replies

 

[razrman8]

Bypass the boost controller and run the line from the compressor housing to the wastegate, see if your problem still persists. If it does, then we can eliminate the boost controller being the culprit.

 

[knochgoon24]

If by front you mean the line going towards the right, then that should be correct.

Try bypassing the MBC like Keenan suggested.

I had a similar problem when one of my MBC lines had a hole in it. You may want to check for that too while you're at it.

 

[2gGst98]

I put new lines on when I put it on. And I had it by passed when I removed the restrictor, and it still does the same thing. Could another vac line having a hole be the culprit?

Meaning I had the stock boost controller bypassed. Also could a bad turbo spike like that?

 

[knochgoon24]

Take the wastegate off and see if you can move the little arm on the flapper by hand. Then check to make sure the wastegate moves when it gets pressure. Maybe something is binding up.

 

[jtmcinder]

And maybe reconsider the original plan to ask for 17 psi from a T25.

 

[97gsxIA]

Figured I'd chime in here, first is there a reason you MBC is far away from your compressor housing/wastegate? It looks like its all the way up by your bov. I have literally 4 inches max of vac hose between the MBC/wastegate actuator and the MBC/jpipe(compressor housing). I'd think there would be no reason to put it all the way up there unless you intended to plug it into something other than the compressor housing/wastegate actuator. Looks almost like you hooked your MBC to that bloost solenoid that should be ripped out already.

I'm just interpretting your picture (not saying its hooked up wrong, just curious)

 

[2gGst98]

I put it up their so I could easily get it to what I wanted. I was going to relocate it when I figured where what boost level is at what turn point.

I will check the waste gate after work, witch im about to go back too. So about a hole being in another vac line is a no on the issue? And the turbo being bad is a no also? I am going to get a 14b in about a month, I just dont want this issue happining then also.

Ill check the wast gate and get back. Thanks again to all the quick replies

 

[slayer450]

its a hollman MBC It is hooked up right. Would a bad t25 spike? I also have the controller all the way down. And unless the pic it gives is supposed to be hooked up oppisitely then its correct. I can take a pik if you want.

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ok so the vac. line comming from the front goes to compressor housing, bottom vac. line goes to waste gate

Knob is turned all the way down.

I do appreciate all the quick replies

Correct me if I'm wrong but wouldn't have the mbc knob turned all the way down raise boost levels? Loosen up on it and see if it drops.

 

[2gGst98]

its all the way down. Twords the - on the knob. I am not 16 years old. JK no offence to those who are and no their stuff. But thanks anyway

 

[GRace]

Yeah, tightning down a mbc will raise boost. Try running it without the mbc and your problems will probably go away. I'm sure the wastegate is fine, unless you still get high boost without the mbc and just a straight vac line hooked up...

 

[2gGst98]

well like I said befor when I removed the restrictor this happened. Thus the reason I got the MBC. But im going to work again so I check the waste gate like knochgoone24 said. But if I have it from the waste gate to the compressor it shuld be at what 12? I dont think I did this like you said knochgoone24. ill try it and see

 

[GRace]

well like I said befor when I removed the restrictor this happened. Thus the reason I got the MBC. But im going to work again so I check the waste gate like knochgoone24 said. But if I have it from the waste gate to the compressor it shuld be at what 12? I dont think I did this like you said knochgoone24. ill try it and see

If all you did was remove the boost controller then had high boost then I would assume there is an open vac line somewhere. Or at least a bad leak. When I test wastegates I put my compressor at 20 psi or lower and add air to the wastegate vac line and see if it opens and closes.

 

[miguelmcv]

Do what Grace Said, Put some air to the wastegate and see if it opens and closes freely.
Also, you should try to connect a line from the turbo to the wastegate, so you will remove the MBC and EBC, This way, it has to fix your problem, If it fixes, then add the MBC and see what happens.

 

[2gGst98]

Grace that is a good way to test it. I was woundering how I was going to do that. I probably would have just tried to move it my self. But if I hook up straight to the waste gate from compressor side, I sould be at what 12psi? Is doing this going to tell me if it is good or bad?

 

[GRace]

Grace that is a good way to test it. I was woundering how I was going to do that. I probably would have just tried to move it my self. But if I hook up straight to the waste gate from compressor side, I sould be at what 12psi? Is doing this going to tell me if it is good or bad?

I don't know what the wastegate spring would be rated to but I would think that the stock spring would open the wastegate at or before 12 psi on a t25 as long as everything is stock. All the wastegate test will do is rule out the wastegate as a problem. If it were me, I would hook just a good vac line from your boost source straight to the wastegate. Then figure out what's up with the mbc or the lines.

 

[clipto]

Blow the t25 get a 14b. That should fix issue with turbo and wastegate sence you would be switchin them. All that is left is if the mbc is bad or not. Kappech kapala.

 

[miguelmcv]

I don't know what the wastegate spring would be rated to but I would think that the stock spring would open the wastegate at or before 12 psi on a t25 as long as everything is stock. All the wastegate test will do is rule out the wastegate as a problem. If it were me, I would hook just a good vac line from your boost source straight to the wastegate. Then figure out what's up with the mbc or the lines.

http://www.dsmtuners.com/forums/newbie-forum/1893-stock-boost-merged-5-7-a.html

 

[jtmcinder]

Blow the t25 get a 14b.

Yes, by my reading of the OP's current knowledge and skills (which is not meant to be demeaning; everyone starts somewhere), a non-bolt-on turbo is exactly what we should be suggesting.

Not.

 

[clipto]

Yes, by my reading of the OP's current knowledge and skills (which is not meant to be demeaning; everyone starts somewhere), a non-bolt-on turbo is exactly what we should be suggesting.

Not.

true I mean the 14b shouldn't be that big of a swap and can get parts for it cheap. But not to mention the t28 is way to much money and buying another t25 is a shamefull thing . But yea it was just a suggestion then playing with that turbo.

 

[2gGst98]

I am doing the 14b swap after summer. I just re-did my whole suspencion, and running auto cross. getting better times now, so when I get to a basic time that I cant get too much lower. Then come 14b and ceddy mod, injector ect. I just got done fixing previous owners mess ups. But that is besides the point.

I will run compressor to waste gate and see what it goes up too. If I am still getting the same situation would that mean the wast gate is bad? ( not nessecarily a bad thing just might make me get a 14b sooner than planed

O yea I also want to get gsx brakes also, but that will come at the same time as the 14b. And it was not a bad sugestion what so ever. I just do things step by step, I will be getting evo scan to log with when I get my 14b.

But thanks to everyone for the info, I changed from JDM Too DSM so I am learning but I am pritty mechanicaly sufficent, Everything on the car is done by me

sorry for grammer I am illiterate, ever seince 5th grade iv been in LD classes. So little slack would be greatfull