GreekDrifter91

how much boost can the stock valve handle? im trying to tune for more boost and trying to increase boost with a MBC and im cranking down on it alot and i still dont see a increase in boost , i saw it peak to 8.0 psi for like a split second and 7.5psi at redline. i have a stage 2 BNR turbo. im just trying to get to 10psi and ill be happy lol

barkz

iTrader: (1)

I think you need to do some research...

GreekDrifter91

i tired and came up with nothing, the charge relief valve or divert valve what ever you want to call it, does it or does it not have a max pressure it can hold?

in the same amount of time you told me to research you could have said the answer, or not have posted at all if you dont know the answer.

KompressorLOgic

iTrader: (6)

what charge relief valve/diverter are u talking about ??

is this an s4 or s5? your signature shows an 87 ,

s4 has a hose going from waste gate to the cold side of the turbo, you just splice the boost controller into that??

how do you have it hooked up?

GreekDrifter91

its a S4 with a JDM S4 engine in it.

and i have a lot of deleted stuff but anyway. one side of it is connected to the TIP and the other to the charge pipe after the compressor before the IC and small line hooked up to vacuum(?) i don't remember but the valve does work.

the MBC is hooked up like it should off the nipple on the compressor side and to the waste gate actuator

i can take pics of it when i get home from work.

RXSpeed16

iTrader: (41)

^+1. Probably a plumbing issue or a defective MBC. Mechanically, they are really simple.

The stock "Air Bypass Valve" regularly holds 10+ psi in good working condition. The absolute max pressure is a bit fuzzy since most people move to an aftermarket BOV and intercooler before the stock valve becomes the limiting factor.

GreekDrifter91

maybe bad mbc i mean this stuff is real simple anyway to "check if the mbc is bad or do i just need to turn the screw some more maybe it needs big adjustments and not small ones.

KompressorLOgic

iTrader: (6)

ohh are u talking about the stock blow off valve? if that's what your talking about then yes it should handle as much boost as the turbo can make.

i would suggest something is wrong with the controller perhaps it is hooked up backwards? or maybe your turning it the wrong way? or not enough? what brand is the controller?

GreekDrifter91

yea sure stock blow off valve but i know that as divert-er valves from other cars lol

i dont know the brand i forget, i can check when i get home, nope im turning it the right way, there is big arrow with a plus sign on it hahaha and i have seen small increase in boost with turning it. i was at like 6psi now im seeing a steady 7.5 sometimes peaking to 8 but that at almost the rev limiter.

and the instructions of how to hook it up are very clear and simple lol

RotaryEvolution

iTrader: (30)

you do not plumb the boost controller to the charge relief/blow off valve...

the WASTEGATE ACTUATOR is what you're looking for and is physically bolted to the turbo.


but i have to ask, do you really think it's a good idea turning up the boost if you're having difficulty with this? read the forums more and roll the dice then.

GreekDrifter91

i think you miss read what i wrote, but i do have it hooked up right. its ok i miss read things all the time

RotaryEvolution

iTrader: (30)

then the blowoff valve does not regulate boost, but if it is set too soft it may leak and cause lower boost. there is no limit for the stock valve that i know of, nor can it be adjusted so i don't know what you're fiddling with but it isn't a stock charge relief valve if it is adjustable.

if cranking up the boost controller doesn't do anything then you either have large boost leaks, an improperly installed boost controller, or a faulty boost controller.

GreekDrifter91

yes, i know it is not adjustable... my original question was what kind of pressures can it hold. and it got answered.

i will double check the lines when i get home but im 100% sure its not on backwards. so its either bad, i have a leak, or this mbc requires a lot of adjustment to increase boost.

when i get home ill take a look.

RotaryEvolution

iTrader: (30)

some MBCs see boost increases immediately off the closed position, others have to be backed out about half way before you start seeing the effects.

GreekDrifter91

yup just need to be backed out a stupid amount i am now much closer to my 10psi goal im peaking at 9.5

RXSpeed16

iTrader: (41)

Glad you got it sorted. I remember about 10 years ago, I was helping a friend install an MBC in an wrx. It was like half a turn to go from "stock" to "I'm going to slide you into that ditch over there". So, it's probably better to have a finer adjustment than absolutely necessary.