Boost Creep(overboost) after intake install.

[Rubberman2003]

I have a 90 gsx. I built a homemade intake from 3" pvc pipe and couplers. After i got it all installed i go and drive it and 2nd gear boost goes up until i hit fuel cut! very scary. I have my mbc screwed all the way in. I have the airbox cut so that it just holds the filter and mas thats it. Im going to try and put the acordian tube back on and see what happens. Right now im venting(no place to put vent tube in the pvc pipe) Any help would be great.

 

[rowlex]

Just an intake should not create boost creep. Check your boost controller, and vacuum lines.

Here is what I would do:

Bypass boost controller, hook the line you T'd with your BOV (or if you are using the boost source off the J-pipe) hook it straight up to the nipple on your wastegate actuator. This will make your car run stock boost if it doesn't maybe you do have creep, or a bad actuator.

 

[Dream On]

Yeah I agree that the intake isn't the problem. Go with what he /\ said. How is the intake by the way? I thought of making one from ABS. Good luck figuring it out.

 

[tstkl]

you said the problem yourself, your mbc is screwed all the way in, that will cause your boost to be at the highest possible setting, all the way out is the lowest boost possible...

 

[rowlex]

you said the problem yourself, your mbc is screwed all the way in, that will cause your boost to be at the highest possible setting, all the way out is the lowest boost possible...

excellent. I've never even used an MBC..

 

[Rubberman2003]

Hmm Ok, i do feel dumb. Ill give it a shot, how far out can i go without the darn screw falling out? If you know what i mean. I also have another problem now, my waste gate arm keeps popping off. There is no clip or anything there. Any ideas on how to hold it on.

The intake is ok, at least i think it is . The coupler that goes to the turbo is a tight fit with the lower radiator hose though. Ill go play with it some more.

 

[rowlex]

Hmm Ok, i do feel dumb. Ill give it a shot, how far out can i go without the darn screw falling out? If you know what i mean. I also have another problem now, my waste gate arm keeps popping off. There is no clip or anything there. Any ideas on how to hold it on.

The intake is ok, at least i think it is . The coupler that goes to the turbo is a tight fit with the lower radiator hose though. Ill go play with it some more.

Unscrew it and find out, just dont let everything fly out everywhere.

Find something you can bend and slide through the hole in the wastegate. Then bend it around to make sure it doesnt fall out. A Paperclip might work.

 

[Rubberman2003]

My Turbox's MBC says that screwing the adjuster in a counterclockwise direction increases boost (that is screwing it out) and clockwise decreases. That is how mine works. Got the directions right in front of my and i tried it to make sure. I put the old acordian hose on it also and it runs fine, right around 12psi until i turn the boost up.

I tried putting something through the hole but i looked at it and it just looks like 2 dimples, it didnt look like it goes all the way through, ill try something sharp and fairly stiff.

 

[rowlex]

My Turbox's MBC says that screwing the adjuster in a counterclockwise direction increases boost (that is screwing it out) and clockwise decreases. That is how mine works. Got the directions right in front of my and i tried it to make sure. I put the old acordian hose on it also and it runs fine, right around 12psi until i turn the boost up.

I tried putting something through the hole but i looked at it and it just looks like 2 dimples, it didnt look like it goes all the way through, ill try something sharp and fairly stiff.

Ok as long as your wastegate arm is staying on there, try the test I posted in a previous post about bypassing the boost controller --with your new intake on. Its VERY hard for me to believe that is what is causing your boost creep.

 

[Rubberman2003]

Ok i want to make sure i understand this and give you some info as well. My stock boost solenoid is not in there, not plugged in, the lines that go to it are gone. My MBC is hooked up to the line that goes to the wastegate and also the line on the (Jpipe) its near where the lower intercooler hose goes on at. You saying just take 1 piece of hose and connecting the wastegate to the jpipe piece? I do have 1 line on the airbox that goes to nothing. But also remember if this doesnt sound right the car ran fine before like this. Thanks Sorry if this isnt a very smart question, but i want to be sure im doing this right. Most likely will be tomorrow morning when i can do it.

 

[Rubberman2003]

Ok i want to make sure i understand this and give you some info as well. My stock boost solenoid is not in there, not plugged in, the lines that go to it are gone. My MBC is hooked up to the line that goes to the wastegate and also the line on the (Jpipe) its near where the lower intercooler hose goes on at. You saying just take 1 piece of hose and connecting the wastegate to the jpipe piece? I do have 1 line on the airbox that goes to nothing. But also remember if this doesnt sound right the car ran fine before like this. Thanks Sorry if this isnt a very smart question, but i want to be sure im doing this right. Most likely will be tomorrow morning when i can do it.

 

[rowlex]

that is exactly how to test the wastegate actuator. vacuum line from the j-pipe nipple to the wastegate nipple. Assuming you have no boost leaks. If you want to be even more sure, find some way with compressed air or a bike pump to pressureize the wastegate nipple and watch to see if the arm moves.

 

[Rubberman2003]

Ok i did what you suggested. With the acordian hose still on and with the mbc bypassed i ran 10-11 psi. Then i put my intake on, still ran 10-11 psi (slightly quicker spool up though??) Then i put the controller back on, all the way closed(which on mine is lowest boost possible) and i still ran 10-11. So i dont know what my problem was. LOl thanks for the advice. My wastegate arms still pops off, the old pin is sheared off inside it though, gonna try to get it out or something.

 

[rowlex]

No problem. You must have had a leak or not fully sealed vacuum hose going to the wastegate.

Sorry dood but I also gotta point out that test was the first responce of mine in this thread!

 

[Rubberman2003]

Thanks. You are very right, sorry about that.


On another note it seems like everytime i touch my car something goes wrong . Timed it and set the idle(needed very little adjustment) drove it, had some engine vibration. Noticed on the top motor mount one of the nuts came off, got one put it on and it still doing it....GRRR

 

[SkyLineGtR-R34]

Hmm Ok, i do feel dumb. Ill give it a shot, how far out can i go without the darn screw falling out? If you know what i mean. I also have another problem now, my waste gate arm keeps popping off. There is no clip or anything there. Any ideas on how to hold it on.

The intake is ok, at least i think it is . The coupler that goes to the turbo is a tight fit with the lower radiator hose though. Ill go play with it some more.

not to be an ass or treat you like an idiot but i think the first question is kind of stupid
I mean, do you even have to ask someone after you saw the accutator arm falling off that you need a clip to hold it?
If you already going to mess up with turbo's and everything you gotta know some basics about it
sorry...just my opinion

 

[Rubberman2003]

I understand where you are coming from. I just wanted specific enough, the pin that goes through it is sheered off, i tried everything to get it out, i was almost conviced that there wasnt a pin, just because it looked to 2 dimples where it was sheered. But i just tack welded a blob on the end of the rod.

 

[rowlex]

I mean, do you even have to ask someone after you saw the accutator arm falling off that you need a clip to hold it?

EDIT#2: looks like i didnt read rubberman's quoted post--i didnt even know you asked that question, OOPS. See my lower post on how to fix it.

With the actuator arm falling off--he would get NO boost. The actuator arm is what holds the flapper door shut. If the arm falls off, the flapper door stays open and he would not be able to boost. So the question he presented is quite a bit different from the actuator arm being the culprit.

Rubberman if you can take a picture of the "pin area" maybe it has broken off? Or find some pictures of the pin area on other turbos to compare. If it's still all in one piece try drilling whatever is in it out. If it has infact broken off, find a way to get something on whatever is left to make sure the arm stays on, like a small washer and have someone weld it. The arm generally never needs to come off so having it welded on would be fine, just dont impede its movement with the weld or whatever you use.

 

[SkyLineGtR-R34]

I understand where you are coming from. I just wanted specific enough, the pin that goes through it is sheered off, i tried everything to get it out, i was almost conviced that there wasnt a pin, just because it looked to 2 dimples where it was sheered. But i just tack welded a blob on the end of the rod.

if it's just the pin that's missing than that's easy to replace
you can take some steel wire and put it in or anything small enought that's gonna fit into that hole - the idea is to keep the arm on the flapper
But if there is a broken part on the flapper then you might follow rowlex's advice
weld a washer at the end so it doesn't fall of - i din't think anyone would even charge you to have that welded
also if you can find a small clamp that might work too

 

[Rubberman2003]

Ive got that fixed. The pin that the arm slides over is there. But there is nothing there to hold the arm on the pin once its slide on. I couldnt get the hole in the pin to open up( force out whatever broke off) so i just put a tack weld on the very end of the pin so if the arm slide down a bit it would hold it on. Works great.

The problem i have now is engine vibration, right around 2500rpms, its not driveshaft or tranny. It does it at idle and in every gear. I have no power lose. It could be my D/P hitting somewhere, or a motormount im not sure. I tried to grab the motor to see if i could pull the engine one way or another and i cant get any play. Ill try brake torqueing a bit tomorrow. Any other suggestions?

 

[rowlex]

Ive got that fixed. The pin that the arm slides over is there. But there is nothing there to hold the arm on the pin once its slide on. I couldnt get the hole in the pin to open up( force out whatever broke off) so i just put a tack weld on the very end of the pin so if the arm slide down a bit it would hold it on. Works great.

The problem i have now is engine vibration, right around 2500rpms, its not driveshaft or tranny. It does it at idle and in every gear. I have no power lose. It could be my D/P hitting somewhere, or a motormount im not sure. I tried to grab the motor to see if i could pull the engine one way or another and i cant get any play. Ill try brake torqueing a bit tomorrow. Any other suggestions?

Glad you got the pin thing fixed

I really have no idea what the vibration could be...I would check my timing marks if my car was doing it. and/or check or replace plugs & wires. Maybe something with the cam sensor but I've never had the problem so it's all just speculation.

Is their any difference when not moving if you have the clutch in or out?

 

[Rubberman2003]

No. I can have the clutch in or out it doesnt matter, any gear doesnt matter, just right around 2500 rpms. I rigged it up so the cars rpms would stay around there, then i got under it, the driveshaft is vibrating near the Transfer case, and the case is vibrating a bit. If i grab the driveshaft and shove it toward the transfer case it seems to "quiet" the vibration down a bit. Im going to make a new thread about it.

 

[rowlex]

No. I can have the clutch in or out it doesnt matter, any gear doesnt matter, just right around 2500 rpms. I rigged it up so the cars rpms would stay around there, then i got under it, the driveshaft is vibrating near the Transfer case, and the case is vibrating a bit. If i grab the driveshaft and shove it toward the transfer case it seems to "quiet" the vibration down a bit. Im going to make a new thread about it.

dude. you are one ballsy mofo

 

[Rubberman2003]

Not sure what you mean But thanks

The car was blocked, and the driveshaft was not spinning when i grabbed it