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Discussion Starter · #1 ·
ppl.. i continue to experience boost cut only running turbo xs mbc at 14psi.. i know ppl out there running 16.5 psi and have no cut.. if i keep the car running high at 5500 rpm with full boost level at 14psi.. i experience a quick jerk and my cel comes on.. why does this happen to me? can someone give me a hint? thanks
 

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Discussion Starter · #3 ·
hum

whats the stock psi showing on a boost gauge? right now i'm showing 14psi with mbc and experience fuel cut?

please check if i hooked up the boost gauge right as well as the mbc.. thanks guys
 

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Your setup looks ok but answer me a question...

For the MBC you only needed to disconnect the hose going to the wastegate and stick the MBC end onto the wastegate (looks like you did this), but what did you do with the hose that you pulled off the WG? - you need to stick a screw in the end of the hose....You shouldn't have disconnected any other hoses (such as the one running to the FBC)

Mine looks like this.

Where did you connect the AIR IN end of the MBC? Should goto the BOV....it would then mean moving the boost guage tap to the manifold...
 

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Discussion Starter · #7 ·
=)

hum.. looks like you have the joe mbc.. wow.. thats a lot diff from mine the way you had yours hooked up.. hum.. i'll have to look in to it a little bit more! thanks
 

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I had the same problem with my TurboXS MBC. But my boost would build and then flutter up and down. It was caused from the o-ring in the middle of the threads of the adjuster screw/jet. My o-ring was damaged and had to be replaced. I haven't yet installed it again and tried it. I will this weekend.

You will need a new o-ring. When I get home I can post the o-ring dimensions. Lucky me, I had 1 of the first 100 MBC's made by TurboXS and had one o-ring on the adjuster screw. The newer ones have 2 o-rings, so I was told by Mark at TurboXS.

Kurlee Daddee
(THE ORIGINAL)
 

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KurleeDaddeeWRX said:
You will need a new o-ring. When I get home I can post the o-ring dimensions. Lucky me, I had 1 of the first 100 MBC's made by TurboXS and had one o-ring on the adjuster screw. The newer ones have 2 o-rings, so I was told by Mark at TurboXS.
COUGH, COUGH, joe p, COUGH, COUGH, COUGH

-Jim
 

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Discussion Starter · #11 ·
what the heck

damn man, i bought my turbo xs boost control 2 wks ago.. brand new.. it might be defective? aww hell no man! so what is the stock psi suppose to show on boost gauge? 10psi? thanks
 

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Re: what the heck

gqzboy said:
damn man, i bought my turbo xs boost control 2 wks ago.. brand new.. it might be defective? aww hell no man! so what is the stock psi suppose to show on boost gauge? 10psi? thanks
Stock pressure in 1st and to a certain extent 2nd gear, is lower than 3rd gear +......People see anything from 8-10psi in 1st.
 

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Discussion Starter · #13 ·
in that case. my boost gauge is not off.. because its showing 10psi when i did not have a mbc installed, now its showing 14psi experiencing fuel cut, so that means logically, the problem is coming from the "MBC"...
 

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gqzboy said:
in that case. my boost gauge is not off.. because its showing 10psi when i did not have a mbc installed, now its showing 14psi experiencing fuel cut, so that means logically, the problem is coming from the "MBC"...
Mmm...you know anyone else with an MBC that you can trial?

Pre-MBC, what gear were you seeing 10psi...If you were seeing 10psi in all gears then your boost guage is out :(

Just get a $45 JoeP or a $49 Boostvalve I am sure that you will find that something is wrong with the XS....

Michael
 

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Or, if you know anyone with Delta-Dash they can plug it in and you can take a spin. This will show you how much boost the ECU is seeing.

Carlo
 

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Discussion Starter · #16 ·
...

delta dash huh? well never heard of such device. and naw i don't really know that many ppl in hawaii who drives suby. hum.. i really don't want to go out there and buy another mbc, i just paid 100 and something for this turbo xs one.. just wanna know what the problem is.. i don't think my boost gauge is off.. as it works perfectly, and i have check all the vacume hoses, non are strained in any way. i'll continue to investigate.... not like i know anymore things to check on.. haha
 

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Discussion Starter · #17 ·
oh yeah

my STI genome boost gauge shows max at 2.0, it says X100pa or something like that.. does that mean my boost gauge is measuring in BAR??Since its straight a JDM part. if that is the case.. SHOOTS.. my bad.. i might be doing 1.4 bar which is over 20 psi......
 

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Re: oh yeah

gqzboy said:
my STI genome boost gauge shows max at 2.0, it says X100pa or something like that.. does that mean my boost gauge is measuring in BAR??Since its straight a JDM part. if that is the case.. SHOOTS.. my bad.. i might be doing 1.4 bar which is over 20 psi......
Uh huh. If you were previously interpreting .14 MPa on your STi boost gauge as 14PSI , getting fuel cut and CEL, you were indeed overboosted. Try dialing it back to .11 MPa.
 

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Discussion Starter · #19 ·
...

my bad.. its x100kpa.. what kinda measurement is this? psi or bar? thanks
 

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Hey - I'm in Hawaii and I'm about to install an MBC in another WRX owner's car. We can check out your install. Or maybe even try his MBC out in your car (up to him)... :) I have an extra HKS MBC lying around in fact.

Aloha,
Richard...

P.S. If you're really desperate to see if your boost gauge is stock, run a Mityvac on your manifold T, route it towards the interior of the car through the hood/open window/whatever (remember this is VERY temporary) and get yourself into boost. Match up the testing gauge versus your boost gauge to see if they read the same...
 
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