Too much boost

[Xero_Tolerance]

Hey, I just installed an intake pipe, autometer 30-0-30 boost gauge and an mbc. I have the MBC totally unscrewed to see what the boost was like stock, but when I get on it and get full boost it spikes around 23, which is higher than I would like, but not HORRIBLE. The problem is when I get above 19 or so the car starts to jolt. I'm not sure, but I was thinking maybe it's knocking, or I also read that dsms with high boost don't like the NGK plats, which I have in the car atm, so I just ordered some of the BPR7ES plugs. I'm just wondering what the problem could be. I mean if it's boosting that high with the screw totally undone how am I supposed to turn the boost down? Any help would be appreciated, thanks.

 

[nine5raptor]

What brand/type of boost controller? Is it a bleeder or ball and spring type? Homemade or namebrand (what brand?)?

You may need to screw it all the way in depending on the type.

The jolt you feel is most likely fuel cut. Does it also backfire and spit out a cloud of black smoke? If so, then it is fuel cut. It's the ecu giving you a warning.

 

[Xero_Tolerance]

It's a homemade one that I bought off ebay, it's ball-spring type so I don't think tightening it would help since it'd put more of a force on the spring. I thought maybe it could be fuel cut also in which case I should get a new fuel pump, but I don't really want to spend any more money right now. I'm getting a Joe P MBC so hopefully that will fix the problem. Anyone have any experience with them?

 

[candela]

You can really make a few different designs of ball/spring types your self. As you said typically the tenion on the ball will allow bleeding of the signal and raise boost. However if you place your controller could be leaking or the bleeder could be on the opposite side (i have seen it done with homemade stuff :laugh: ) and its being bled out regardless.

Maybe you should consider running without it until you either figure it out or get a new one (make your own or buy a new $40 hallman). 23psi is quite a bit to be running with your settup (stock). Be careful... if you do not really know what you are doing you can cause a LOT of damage with a turbo. If your BC is not hooked up correctly then it simply will do exactly as you stated...

 

[Xero_Tolerance]

Well I know it's hooked up right, I took it apart and the more u tighten it he more boost. Basically I'm just not going to push it for a while, let off around 18 psi so I don't hurt anything for now, till I get the joe P MBC, then I should be good. It's not that I don't know what I'm doing, I just don't know why the mbc is letting it get to 23 when it's loose, but I know how to fix it. Thanks anyway.

 

[dugjr24]

I would definitely take that MBC off homemade ebay specials are not the way to go. I would bet my next paycheck that you are hitting fuel cut. Ive heard great things about the Joe P. I know people that run that MBC on 24psi with large turbos. I have a hallman personally.

 

[TurBoGs-T]

I bought one of those ebay homejobs. I ran my boost all the way up too. It does have a little hole in the back of it that seems to let air out. Is this causing problems?

 

[nine5raptor]

No, that is a necessary part of the system. Think about this:

Boost builds
Ball/spring valve opens
Pressure is built in the wastegate actuator line
Now the pressure is equalized
The valve closes
Pressure leaks out the little hole

If that hole were not there, the line would stay pressurized (the mbc is a one way valve) and the wastegate would not close, giving you horrible lag the next time you boosted. It is small enough though that it will not leak enough air to cause a performance decrease.

 

[GSX4LIFE]

You know, I find it so odd that people are willing to spend $500+ on an exhaust, $300+ on a fuel controller, $1000+ on an FMIC, and $800+ on a turbo upgrade. Yet, they will by the absolute cheapest, piece of crap, homejob mbc they can find on Ebay. One of the most integral parts of the system, and they will risk using a $10 rig job? Pay $100 for a Hallman Pro, or Extreme XBC. I dont get it.

 

[BoostinAWD]

The spring is too stiff, hit up home depot.
Find something softer.

 

[broox]

man i think i got this exact MBC and the same thing is happening to my car. basically i made a few upgrades and the boost was spiking around 20. so for the last couple months i've kept 1 eye on the gauge at all times to make sure i stay below 15psi (stupid t25).

i finally installed the $5 homemade ball-spring mbc from ebay and now the boost will spike even higher than before! i too have the screw turned almost all the way out, but the spring is barely touching the tip of the screw... is there anything i can do to mod this MBC and make it work? or should i just get a hallman's or joe p or something?

thanks.

 

[STECARS]

from the directions on those mbc's you unscrew out for more boost and you screw it in for less boost. How about yours. are you doing something wrong.? Out is + boost , in is - boost.

 

[eclpsegsx12]

Originally posted by GSX4LIFE
You know, I find it so odd that people are willing to spend $500+ on an exhaust, $300+ on a fuel controller, $1000+ on an FMIC, and $800+ on a turbo upgrade. Yet, they will by the absolute cheapest, piece of crap, homejob mbc they can find on Ebay. One of the most integral parts of the system, and they will risk using a $10 rig job? Pay $100 for a Hallman Pro, or Extreme XBC. I dont get it.

I completely agree. If you dont want to spen a little money for a nice mbc, then you might as well run it to the wastegate until you do buy a nice one..... Personally, i am running the Hallman Pro-Evo Cockpit design MBC and its awesome. Dejon tool has some nice cheap ones, hallman, joe P, and many others.

On a side note, just take that mbc off and run the line to the wastegate for now until your joe P one comes in. It will be easier on your motor this way until the new one comes in.

 

[broox]

Originally posted by STECARS
from the directions on those mbc's you unscrew out for more boost and you screw it in for less boost. How about yours. are you doing something wrong.? Out is + boost , in is - boost.

The "directions" that came with mine say that out is - boost and in is + boost.

 

[nine5raptor]

As it is with almost any ball/spring boost controller.

Bleeder valves are the opposite.

 

[hellotbone]

I was always getting a spike with my MBC with the T25 would hit 20 then sit at 15 PSI till about 5000 then start to fall off or sooner. I got the forced performance WG and would not spike and would hold the boost a bit longer but the T25 always runs out of air for the top end. So I got a 14b for 50 bucks and put it on for another 25 bucks and hold 17 PSI till redline all day long no spike nothing.

 

[broox]

well, i just ordered a joe p from boostcontroller.com. hopefully that will do the trick. it makes me feel a little more comfortable than modding my current one, and wtf, it's only $40 right...

 

[rabidfox]

when I had spiking problems with my mbc, I just chopped the lines to about 3 inches, just enough so that both lines will fit securely on the outlet nipple and the wastegate nipple, no spiking problems, creeping problems when I put my downpipe on, thats another story...

you might want to try this

 

[broox]

holy cow i love joe p. that boost controller fixed everything... and after 15 minutes of driving back and forth down my street, i've got it set perfectly.

it's been a couple months since i've felt my foot hit the floor underneath the pedal... always had too much boost to floor it before.

much love to joe p!

 

[TurBoGs-T]

Originally posted by broox
holy cow i love joe p. that boost controller fixed everything... and after 15 minutes of driving back and forth down my street, i've got it set perfectly.

it's been a couple months since i've felt my foot hit the floor underneath the pedal... always had too much boost to floor it before.

much love to joe p!

I'm in that boat now. I haven't been able to do any Hwy pulls cause it will cut on me.