boost stops at 10psi????

[gsxrtalon]

alright guys, I have a 2g tsi fwd and I have some mods(nothing crazy)(check profile) and I recently put my boost gauge in and it reads only to 10-11psi when im out driving and thats all I can get. I've turned my boost up and it still reads the same, any help would be appreciated, thanks in advance.

 

[oldman]

Test run with the actuator nipple open, this will result in all out boost so feather the throttle accordingly. If in fact you get 10+ psi, the mbc is the problem.

 

[gsxrtalon]

thanks for the reply oldman,

I never thought of that, (im kinda new with dsm's but im tryin to learn
however, my boost controller does actually have a minor problem, when i first got it i mounted it and ran the hoses as i was in my car one of my idiot buddies decided to take the alan wrench and play with it(tighten/loosen it) well he kept tightening it down and stripped the screw inside it. I jb welded it and i "thought" it fixed it, maybe not? And by "feather the throttle I take it you mean got just hope in my car and put the pedal to the metal right? Sorry if i dont understand completely
thank you again
appreciated

 

[oldman]

When you leave the actuator nipple open (remove the hose between the mbc and actuator and cap off the mbc side), boost should shoot straight up to 20+psi, as soon as you see it go past 15psi let off the throttle.

 

[tstkl]

and with that small of a turbo it happens fast, so be very careful...

 

[ddavisaf]

And replace your mbc

 

[SethA]

It wouldn't hurt to test for boost leaks either. That will help you verify your boost gauge is working and rule out the possibility that you have a leak.

Seth

 

[gsxrtalon]

thanks guys for all the help

Im goin to check the mbc saturday at our shop. I have the turbo xs mbc do you guys have any suggestions on a good mbc I can get to replace it if it needs to be.

 

[oldman]

thanks guys for all the help

Im goin to check the mbc saturday at our shop. I have the turbo xs mbc do you guys have any suggestions on a good mbc I can get to replace it if it needs to be.

http://www.dsmtuners.com/forums/showthread.php?t=193635
This guy has the opposite problem as you but on the same mbc.

 

[rdnek1112]

i suggest u use a hallman mbc they have a ball and spring unlike the turbo xs havng a bleeder valve.

 

[gsxrtalon]

after reading mig233's posts I believe we have the same problem. Thanks for the help guys again, i'll post saturday and let you know.

p.s I know this might be uncalled for however, the more i read the more I see the "wot" coming up, sorry, like i said im kinda new......what exactly does that mean? Ive tried finding out by reading posts but havent figured it out yet

 

[oldman]

WOT = WIDE OPEN THROTTLE

 

[gamingguru]

WOT = Wide open throttle = gas peddle on the floor.

 

[Talesin]

Ball and spring. I've got a Dejontool MBC now, and it seems to hold reliably up to 19psi (all I've set it to so far).

Plus, they're fairly cheap. Heck, you can make them yourself, with the right parts.
I'd just buy one though. Forty bucks, boom. Done.

 

[gsxrtalon]

well, I took my car to our shop today and pulled the actuator hose off and capped it and found out REAL QUICK that it was the turboxs mbc that wasnt working right. You guys werent kinding about the boost rocketing up either Problem solved, thanks guys for the advice and help.....ill post new info when i get my new mbc.

 

[gsxrtalon]

ok i order a joe p mbc and got it today. I took out my turbo xs and put the joe p in. I STILL CAN NOT BOOST PAST 10-11 PSI. I dont understand!?!? Also, the other night my car started acting funny. Ill be in 2nd gear and go to give it gas and it will start to build boost and then nothing happens, no power its just like its sucking air and not producing power. My boost gauge still reads its building boost but the car doesnt go anywhere. Please help me out guys. Im right in the last stages of installing my evo 16g but i dont want to install it if something is seriously wrong.

PLEASE HELP..................WISEMAN...........ANYONE!!!!!!!

NVMYTSI
(ps. i havent installed any of my evo 16g upgrades yet, waiting due to this)

 

[EvolvingGST]

you my friend, like me and have a huge boost leak... i suggest testing it... pressure testing it

 

[gsxrtalon]

thanks for the reply jason, I will do a boost leak test asap. I have never done one before so I'll try to do my best with it I have the vfaq page on how to make a tester so i'll go from there.

thanks

anymore suggestions please post

 

[hiimt0ny]

thanks for the reply oldman,
And by "feather the throttle I take it you mean got just hope in my car and put the pedal to the metal right? Sorry if i dont understand completely
thank you again
appreciated

no he means just eaz on it enough to see if you go past 11psi because if not, with the eacuator open you could hit max boost and hiit fuel cut and cause engine damage.

 

[oldman]

ok i order a joe p mbc and got it today. I took out my turbo xs and put the joe p in. I STILL CAN NOT BOOST PAST 10-11 PSI. I dont understand!?!? Also, the other night my car started acting funny. Ill be in 2nd gear and go to give it gas and it will start to build boost and then nothing happens, no power its just like its sucking air and not producing power. My boost gauge still reads its building boost but the car doesnt go anywhere. Please help me out guys. Im right in the last stages of installing my evo 16g but i dont want to install it if something is seriously wrong.

Let's go back to the basics,

1. How's the mbc hooked up? In detail please.

2. Perform that boost leak test as suggested.

3. Perform a compression test.

 

[Crawford]

while incorrect installation seems to be the culprit here (and oldman is all over it) I'll just add for the people who search for low boost and end up here....


My DIY (mcmaster-carr variety) ball and spring MBC seems to get a piece of something/anything caught in it 'bout every two months or so....this little piece of carbon, grit, old vac line piece, or whatever then holds the ball just a tad off the seat and boost controller starts sending pressure to the actuator all the time.

The result is boost seems to hit a wall at 11-13psi in the 3000-5000 rpm range while your buddies wimpy v-tec slaughters ya.

Also some of the housings don't seem to seat the ball very well and leak a bit too. A quick tap with a brass drift and a hammer against the seated ball usually produces an acceptable seal if this is your problem.

 

[gsxrtalon]

oldman,

I have the joe p mbc and the bottom nipple is hooked up to the wastegate actuator and that is split into a "Y" and that same line is going to the turbo housing itself(under the actuator) the side nipple(off of the mbc) I have going into the line coming off my greddy type rs bov. I just dont understand, this all just started happening? Thanks for the help.
(ps my motor just got rebuilt, so I think the compression should be good but wont hur to check)

 

[oldman]

I have the joe p mbc and the bottom nipple is hooked up to the wastegate actuator and that is split into a "Y" and that same line is going to the turbo housing itself(under the actuator) the side nipple(off of the mbc) I have going into the line coming off my greddy type rs bov.

Remove the Y, one line goes from the mbc to the actuator and cap off the compressor nipple. How was the TurboXs hooked up? What directions did you follow?

 

[gsxrtalon]

oldman,

so remove the "y" and keep the hose running to the actuator but remove the line goin to the compressor housing? Cap the housing? That is the same way I had the turbo xs hooked up.......with the "y" and tapped into the bov line to the intake mani. Thanks

 

[oldman]

oldman,

so remove the "y" and keep the hose running to the actuator but remove the line goin to the compressor housing? Cap the housing? That is the same way I had the turbo xs hooked up.......with the "y" and tapped into the bov line to the intake mani. Thanks

Both the T off the bov line and the compressor housing nipple are pressure sources, you only need one, not both. A MBC takes in the pressure source (side nipple), blocks it until the spring tension in the mbc is reached, releases pressure to the actuator (bottom nipple) signaling it to open the wastegate flapper. The way it's hooked up right now, you're basically bypassing the mbc by connecting the pressure source (compressor housing) directly to the actuator through the Y, causing the flapper to open at the spring tension in the actuator, roughly 10-12psi. The TurboXS unit is probably good as well.