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

 

[oldman]

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.

Remove the hose between mbc and actuator and cap off the nipple on the mbc with a vacuum cap. Just want to make sure you understand the desire result is for boost to shoot through the roof, watch that boost gauge very closely. As soon as you see it go close to 20 psi, it's time to shut down.

 

[captd108]

yeah i understand the hoping for more boost than normal but just wanted to see what i did with the other lines. Ill try this hopefully friday afternoon and it ends up just being the boost controller. Thanks

 

[captd108]

o and just out of curiousity, is the mbc supposed to bleed off alot of air during idling cuz mine does and am wondering if that is normal.

 

[oldman]

o and just out of curiousity, is the mbc supposed to bleed off alot of air during idling cuz mine does and am wondering if that is normal.

Do you mean during the leak test or idle? When car is at idle you have vacuum (-psi) so you shouldn't be leaking air there. If anything you would be sucking in air.

 

[mastadogg2]

ok the part on the MBC that is for the wastegate actuator u wont beable to blow into.. and the part that T's off into the boost source.. compressor housing, intake manifold, or intercooler plumbing you will beable to blow air into through the mbc so take off the tubes and see which one is which before you end up ruining your car.

 

[mastadogg2]

also at idle you want atleast 20psi of vacuum... well inbetween 15-20. i wanna make sure your reading your gauge right.. you do realize you cant read the psi until the cars at WOT .. I know guys that thought adjusting there mbc sitting still and looking at there vacuum they thought was the boost .. im just checking..

 

[mastadogg2]

o and just out of curiousity, is the mbc supposed to bleed off alot of air during idling cuz mine does and am wondering if that is normal.

no..........

 

[mastadogg2]

dont mean to hijack this thread but also if your using a BLEEDER VALVE type mbc thats junk.. thats just a controlled boost leak you dont want that. get a ball & spring type mbc and it will make life alot easier.. get one from www.boostcontrollers.com . There good guys they ship extremely fast and are very helpfull with information.

 

[oldman]

also at idle you want atleast 20psi of vacuum...

You mean 20 Hg = -10psi, not 20 psi. You should be at about 18Hg with the stock cams.

 

[captd108]

well in the end it was the boost controller after school i unhooked the line from the wastegate going to the mbc as oldman said to and capped the mbc and just watched the psi jump straight to 20 sumtin and i knew rigth then i needed a new bc. Went straight to turbotrix since its 2 min away and picked up a hallman bc and now i got it on 15psi and holding without a problem. Thanks for all your help this helped me get rid of all my leaks and realize my mbc was done. O by the way mastadogg i dont have any vaccuum readings on my boost gauge its only boost measurements. Thanks again for all your help guys.

 

[oldman]

I like happy endings.

 

[mastadogg2]

You mean 20 Hg = -10psi, not 20 psi. You should be at about 18Hg with the stock cams.

yup my bad =)