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NG900 & OG9-3 Performance, Mods & Tuning Covers Tuning & Performance modifications for the NG900 (1994 to 1998) & OG9-3 (1999-2002) & '03 Convertible

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Old 10th January 2007
Boostd GVR4 Boostd GVR4 is offline
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Default boost issue??

Well, ok
I have had a regular pos Manual boost controller on my car. Now I could never get boost to stay at one spot. It would spike to 15 then drop to 10. Now I had a turboXS dual stage from my galant that I put on my 93. Its a bleeder type. I cant get boost to adjust at all? It just spikes to like 18-19 then cuts. I dunno whats up with it?
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1999 Saab 93- Daily Driver- custom CAI/Koni Springs/GenSAAB 25.5 RSB/Autometer Boost gauge/MP shortshifter/rear muffler delete/RFL BOV
1991 Mitsubishi galant VR4-1285/2000- work in progress
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  #2  
Old 10th January 2007
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Mike W. Mike W. is offline
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Anything above 15.5psi will result in a fuel cut on Trionic 5 cars.
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Old 10th January 2007
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SPATL SPATL is offline
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bleeder style MBC's are a poor design. The bleed allows air through all the time, too much or too little. Sppol up is slower than ball and spring mbc's. You are going to have to find a happy medium with the bleed style, enough the open the wastegate with increased boost under 15.5psi.

If, on the otherhand, you change to a ball and spring style MBC you'd be better off.
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Old 11th January 2007
Boostd GVR4 Boostd GVR4 is offline
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yeah I couldnt get boost to come down at all. It was like it was open wastegate. So I put my other one back on. One thing i was surprised about is that I know boost cut is about 15psi, but it would go WAY over that. I was hitting 19psi then boost cut kicked in.
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1999 Saab 93- Daily Driver- custom CAI/Koni Springs/GenSAAB 25.5 RSB/Autometer Boost gauge/MP shortshifter/rear muffler delete/RFL BOV
1991 Mitsubishi galant VR4-1285/2000- work in progress
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Old 11th January 2007
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There is one reported case of a user of this BB that his fuel cut was around 19psi without a modified ecu. His name is Ben. I am not sure why that happens but it is an unusual case. Be very carefull with that high of boost with stock ecu. There is an understanding that stock fuel trim only fuels up to around 17psi so if you are at 19psi, you are probably running quite lean. Get that checked out with either a Wide ban a/f gauge or on a dyno.

You stated, "It was like open wastegate".

actually it was more like "closed wastegate."

If the wastegate opens, you dump boost out the exhaust. If the wastegate stays closed, all boost goes to to the engine.

Check your MAP sensor and vac line to the map for leaks. If that hose is bad or leaking, the MAP does not see the pressure at the manifold and only fuels for what it reads. Thsi would cause lean running conditions and potentially a blown engine.
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Old 11th January 2007
Boostd GVR4 Boostd GVR4 is offline
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Quote:
Originally Posted by SPATL
There is one reported case of a user of this BB that his fuel cut was around 19psi without a modified ecu. His name is Ben. I am not sure why that happens but it is an unusual case. Be very carefull with that high of boost with stock ecu. There is an understanding that stock fuel trim only fuels up to around 17psi so if you are at 19psi, you are probably running quite lean. Get that checked out with either a Wide ban a/f gauge or on a dyno.

You stated, "It was like open wastegate".

actually it was more like "closed wastegate."

If the wastegate opens, you dump boost out the exhaust. If the wastegate stays closed, all boost goes to to the engine.

Check your MAP sensor and vac line to the map for leaks. If that hose is bad or leaking, the MAP does not see the pressure at the manifold and only fuels for what it reads. Thsi would cause lean running conditions and potentially a blown engine.
yeah I meant closed wastegate. I always think open wastegate is like an open vaccum line..
But yeah I know. I put the other boost controller in and now its normal. I get fuel cut at about 15psi. Looks like Ill be buying an ecu in a month or so.
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1999 Saab 93- Daily Driver- custom CAI/Koni Springs/GenSAAB 25.5 RSB/Autometer Boost gauge/MP shortshifter/rear muffler delete/RFL BOV
1991 Mitsubishi galant VR4-1285/2000- work in progress
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