raising boost on my b16g

[captd108]

for some reason it seems that i cant raise my boost passed 12-14 psi on my big16g. The only way i think this would happen is if the line going from the wastegate to the mbc has a leak in it and is losing pressure. Do you think this is possible or are there any other reasons why this might happen? Thanks for your help

 

[captd108]

another reason i think its around the mbc area is b/c if i was actually raising the psi of the turbo i would be hitting fuel cut being that i am on 450's still and pretty much untuned on the afc. If all the extra air that i was adding was getting into the mixture i would be running lean and hitting fuel cut. So somehwere before all that im losing air i beleive. I dont beleive its the boost gauge either b/c on the t25 it would read the psi without a problenm even when i had it up to 16psi.

 

[oldman]

Don't WOT any more until you solve this problem, depending on the cause it may kill your turbo. This is what I would do.

1. A REAL BOOST LEAK TEST. I say this first because you want to be sure the system is leak free before you pull WOT for testing. If problem persists after you fix all leaks, go to 2.

2. Bypass the mbc and connect the pressure source directly to the actuator. If problem solved, it's mbc related. If not, go to 3

3. Check the turbo for shaft play and licp and ic for oil, you could be dealing with a dying turbo but I doubt it.

Good luck.

 

[captd108]

well ive checked the turbo thinking the same thing and no oil in pipes, and no shaft play on the turbo also ive had the turbo for a little over a month now so i was thinking that if it was that itd be getting worse each day and be burning oil but oil level is still ok. I am planning on checking for air leaks but still dont get that whole mbc bypass thing. What would cause the mbc to give out also?

 

[captd108]

i rechecked all my vaccuum lines and ic pipes and intake pipe and everything and tightened down everything to as far as it would go without breaking the clamps. I was wondering however mabye i have my mbc hooked up wrong, even though it worked the way it was supposed to with the t25. I have one end coming from the wastegate actuator and the other going to a tee b/w the bov and the intake manifold line. The jpipe boost source is capped at this point. I am thinking mabye i should have it come from the j pipe instead of the tee, would this make a difference?

 

[oldman]

I had a feeling you were going to do a visual boost leak check, that's why I had capitalize REAL BOOST TEST in my first post. Take it from some one who has done it many times, you'll be supprised at the result if you do one of these. http://www.vfaq.com/mods/ICtester.html
I'm willing to say it would be a miracle to achieve no leak after a turbo, IC or IC pipe install. A boost leak test should be a mandatory follow up after any types of work done which involves the intake trac. In your second post you had mentioned you were hitting fuel cut, boost leak is one of the most common cause of an early fuel cut. If you're still concern about the mbc, you can answer that by just follow my #2 suggestion. Please don't pull WOT anymore until you're 100% sure there're no boost leak. Depending the size of the leak, you can end up killing your turbo by over boosting it. Good luck.

 

[mastadogg2]

could be an exhaust manifold leak

 

[captd108]

i did not say i was getting fuel cut, i think i just worded all that wrong, sorry . I meant it as i would expect fuel cut if i was actually getting more boost than what my gauge was telling me. Also if there is a manifold leak how would that effect everything. I dont beleive there is when cuz i tightened all the bolts as far as they could go without snapping them but then again i could be wrong. Ill check those too. I also do plan on doing a real boost leak test but dont have the materials to do it right now so that is why i went over every single clamp and hose and redid them all to make sure they were done correctly with new clamps. I still dont understand what it means to bypass the mbc. What do u do with all the lines that go to it and from it i mean. Sorry if im asking too much im just kinda surprised as to why i cant find where the problem is coming from. Thats why i was wondering mabye i should run the boost source line from my mbc into the compressor housing and see if that could be the problem.

 

[oldman]

1. Changing the boost source from bov to turbo outlet will not make much of a difference if any, but you can easily test that theory yourself.

2. To bypass mbc in order to rule it out, remove the hose from the T to the mbc from the mbc side and connect that directly to the wastegate actuator. If problem persists, you can rule out the mbc.

3. After my fmic and pipes install I went through and re-tighten all t-bolt clamp and gaskets three times and was having the same problem as you're describing. When I finally made the tester and hooked up the compressor, I found total of 8 leaks three of which were huge. I'm still trying to figure out whether the leaks had helped facilitate the death of my 16G due to all the WOT pulls I did between the fmic install and boost leak test. No one ever have a boost leak test material handy, it's up to you to go to Home Depot and make one.

I'll not push you anymore about the leak test after this post, just hoping you would learn from other's mistakes. I guess for some, finding out for yourself is part of the learning curve.

 

[rowlex]

3. After my fmic and pipes install I went through and re-tighten all t-bolt clamp and gaskets three times and was having the same problem as you're describing. When I finally made the tester and hooked up the compressor, I found total of 8 leaks three of which were huge. I'm still trying to figure out whether the leaks had helped facilitate the death of my 16G due to all the WOT pulls I did between the fmic install and boost leak test. No one ever have a boost leak test material handy, it's up to you to go to Home Depot and make one.

I'll not push you anymore about the leak test after this post, just hoping you would learn from other's mistakes. I guess for some, finding out for yourself is part of the learning curve.

I will second this statement. You HAVE to do a real boost leak test. I went through the same issue a week or two back. Oldman told me to do a leak test, of coarse everything was new so I didn't think there was.

Ran the test, I had gaping leaks all over the place; Oldman: my j-pipe had a HUGE leak on it cuz one of the bolts backed out. My BOV set screw leaked, and I had completly forgot to tighten one of my couplers. I had it on their "snug" when I was test fitting and never went back to secure it correctly. They are all fixed, and most everything held 30psi w/o leaking too much.

P.S. If you have an aftermarket BOV try tightening the adjustment screw down. Mine wasn't tight enough and at around ~14 psi it was blowing open and killing performance.

 

[oldman]

Ran the test, I had gaping leaks all over the place; Oldman: my j-pipe had a HUGE leak on it cuz one of the bolts backed out. My BOV set screw leaked, and I had completly forgot to tighten one of my couplers. I had it on their "snug" when I was test fitting and never went back to secure it correctly. They are all fixed, and most everything held 30psi w/o leaking too much.

ha ha, good job. I was waiting for you to update the other thread. Are you still creeping?

 

[captd108]

i thank you all for your help, and i will be doing a REAL boost leak test this weekend, and ahving someone else hopefully check everything over twice for me as well. I do understand the importance of checking for leaks i was just trying to do with what i had available with me at the time and trying to do the best i could. I go to school in the am and work directly after and by the time i get out everythings closed. Once again thanks and ill let you know of my results this weekend

 

[captd108]

well i got around to doing a leak test today and well i actually did find one big one in one of my ic pipes, i took care of that one and then found two ohter ones on the ic itself. When i bought the car the person put a grill onto the ic itself and held it by 4 screws that went into the ic apparentyl 2 of them were stripped and are leaking a little from the bottom. someone told me to go to a radiator shop and get the holes closed so i will be doing that sometime this week hopefully. I'm not sure if this will solve my problems im worried that i still missed one or two so i will try and get someone else to look at it also around me, but im still happy since theres one less leak that i need to worry bout and two that i know where they are.

 

[oldman]

well i got around to doing a leak test today and well i actually did find one big one in one of my ic pipes, i took care of that one and then found two ohter ones on the ic itself. When i bought the car the person put a grill onto the ic itself and held it by 4 screws that went into the ic apparentyl 2 of them were stripped and are leaking a little from the bottom. someone told me to go to a radiator shop and get the holes closed so i will be doing that sometime this week hopefully. I'm not sure if this will solve my problems im worried that i still missed one or two so i will try and get someone else to look at it also around me, but im still happy since theres one less leak that i need to worry bout and two that i know where they are.

Good, make sure you repeat the leak test after those two holes are patched up, there may be more.

 

[captd108]

well i went to go get those holes taken care of today and they just said to jb weld them rather than spend alot more for the same objective. Well i did as they said and it worked i have no air leak there anymore, and i found out that one of my couplers had a rip through it, and that my mani- turbo bolt got loose and was just dangling there. So i fixed all these things and the car pulls alot better than it did. It went to about 13psi 1-2 more than normal. Should i try raising it and see what happens?

 

[oldman]

I don't know how big the holes were on the IC so I'm a little worried about the jb weld holding up, make sure you keep an eye on them. Did you pressure test the system until it can hold 20psi reasonable well? If so, go ahead and turn that baby up. Post back.

 

[captd108]

the holes were probably about under a 1/4" in diameter nothing big.

 

[mastadogg2]

haha.. i told you.. exhaust manifold leaks are bad.. i have 2 bolts missing on mine right now and it makes a HELL of a difference.. gotta retap 2 holes on the head. =)

 

[captd108]

yeah well, i thought that would solve my problems and the little jump in psi i noticed meant nothing cause it still steadily sticks b/w 12/13psi. I tried using a different pressure source (the jpipe) and actually dropped my psi down to 10. I really dont know wtu it could be right now im really thinking its the boost controller, but i always looked at joe p. ones to be very reliable. i dont know what on the turbo could be causing that problem ive had that turbo for about a month and a half now and no movement at all on psi. Ive really only tried to cahgne the psi within the past 3 weeks though and noticed it wont budge. My friend had a joe p. mbc on his evo and he said that it really couldnt hold boost past 21 on his stock turbo (16g) so he got a hallman one, any other suggestion on what any of you may think it could be?

 

[mastadogg2]

I use hallman pro rx .. works very well.. make sure you have your mbc hooked up right as well.

 

[captd108]

my mbc has been on the same way the whole time. the side opposite screw going to t at bov/intake mani and the side nipple going to the wastegate... could it be that since all im getting out of the car is the wastegate boost pressure?

 

[mastadogg2]

well if it wasnt hooked up right the car would probably feel ungodly quicker then normal because there wouldnt be any kind of boost control

 

[captd108]

well i was able to get it to 17psi with no problem on the t25....so what would make it go bad out of nowhere and not be able to hold any boost?

 

[oldman]

Alright let's re-group a little. Fixing the two holes on the ic was where we left off, did you continue the leak test after that? System holding 20psi? The fact that pressure dropped 2-3psi after you switched the pressure source to the J-pipe is an indication there's a leak somewhere in between causing a delay on the actual boost pressure reaching the actuator.

If you've completed the leak test, let's do a test and narrow things down a little.

Do a test run with nothing connected to the actuator. Be carefull, doing this will give you all out boost so shut down some where around 20psi. If you're still boosting only 12-14psi, I would say problem is either bad turbo, huge exhaust leak before o2 housing or a huge boost leak . If you went beyond 14psi and more fairly quickly, turbo is good and the only thing left would be the mbc.

You can see that boost leak plays a big role so it's important you make sure the system is leak free. Good luck and post back results, hopefully it would be good news this time.

 

[captd108]

yes i redid the leak test a couple of times just to make sure everything was fine, replaced the rubber coupler with the cut in it with a new one, and all was good as far as i could tell. put some soap and water on all things to insure that they were holding and everything seems good. I was gonna ask how to do the mbc test again cuz there is one thing that bothered me about it that left me confused. The side that normally goes to the t in the bov now goes to the actuator, correct? Then where does the other line go is my question?? Or do you just take out the wastegat actuator line and leave it unplugged? Thats where im lost right now. The only reason i think its the boost controller is b/c im only getting wastegate pressure which is the 11-12 psi when i asked the person that had it before and he had no problem getting it at a higher psi. What i thought was more psi was probably me misreading my gauge perhaps b/c it was only once or twice that it happened. But the ten psi when i went to the jpipe source was constant. So i want to try the mbc and see what goes on there that way i know what i need to do. Thanks for your help