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Forced Induction All questions and problems regarding Superchargers, Turbos, NOS, ZEX, intercoolers, water injection, etc.

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Old 06-28-2005, 01:46 AM   #11
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Default Car is fixed!

Thanx to all who replied with the great help. Took a look at it Sat. and the vacuum T under the snout had a tear along the under side. As I couldn't find anyone to sell me just this T I just made on from a male T and some hose.

Geez....car is alot quiter now. Interestingly, while it hauls it seems to build boost more slowly according to the gauge and doesn't seem to go past 5 psi (If I remember correctly it used to go past that.....and quickly!).

Anyways, does anyone know of a manual that has some details on this car that INCLUDES the */C info. The haynes we have stinks as it doesn't even mention the */C. Is the Chilton better?

Will look into the suggested mods (been too busy taking care of GM crap build quality until now to even bother..........) Thanx again...

Cheers,

Sunset_Z
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Old 06-28-2005, 03:07 AM   #12
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Buy the factory service manuals from www.helminc.com or Ebay. Nothing else covers the SC.

I suspect your vacuum fitting is too restrictive, and the BCS is dumping boost. You should have 7-8psi minimum with a stock pulley.
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Old 06-28-2005, 06:59 PM   #13
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Quote:
Originally Posted by willwren
Might be a good time to do the boost bypass and BCA optimization trick.
i did the boost bypass but what is the BCA optimization trick?
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Old 06-28-2005, 07:18 PM   #14
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Pre-loading the BCA by loosening the screws and rotating it in the counter-clockwise direction (is that the right direction?) . Should be a link in Techinfo. Snappier boost response. You get into full boost quicker.
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Old 06-28-2005, 07:37 PM   #15
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what i did is loosen the nuts(3 nuts), bring it down (black cylinder)and retight it.thats
called boost bypass ? right?

so how i do that bca optimization, cant see what it is, the boost control solenoid?


so what and where i do that bca one? sorry to ask



also, with boost bypass, the car seem to have less high-end power, normal? but i still
beat my quarter mile time.
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Old 06-28-2005, 08:47 PM   #16
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You just described the BCA trick.

The BCS bypass involves taking the rubber vacuum line off the bottom of the BCA (black cylinder) and moving that end to the other post next to the other end of the vacuum line on the little black box (BCS).
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Old 06-29-2005, 07:30 PM   #17
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ok, but if you unplug the rubber line from the cylindra, what will go there? sorry, not a pro in mechanics

and for the line at the end of bcs too ? ill check it tonight on my side but furtherexplanation or a link to a "how to do bcs bypass" may be it should be in techinfo, the difference between bca optimization and bcs bypass.
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Old 06-29-2005, 07:40 PM   #18
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ok, i just check it, so you dont use the black cylinder anymore?

and i need a longer rubber line, right?


so what was the use of that black cylinder if its bypassed?

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Old 06-29-2005, 11:28 PM   #19
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Okedokee.

The BCA only needs the vacuum line to the top to operate. It works on pressure difference between intake manifold pressure and ambiant air pressure. The bottom side of the BCA is allowed ambiant air pressure through the BCS, normally. When the PCM determines the need for less boost (during a shift, during knock, etc.), it makes the BCS increase the air pressure to the bottom side of the BCA, making it rotate the wastegate valve open as far as it sees fit.

You should only use the BCS bypass if you plan on letting off the gas a little when you shift to avoid shortening the life of the tranny. If there is knock, the PCM should most likely pull timing if it sees no boost reduction when it thinks there should be some.
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