How do i bypass the boost control valve???

[cobaltssblu]

i recently just put in a 3.25 pulley in my Cobalt SS but it did not seem to give me any more boost. but i cant figure out how to bypass my boost contoll valve how do u do it?

[Sp00ner]

Hmmm... None at all? What SHOULD the pulley be giving you, around 14?

[cobaltssblu]

yea i should be getting around 14 supose to be a 2 lb upgrade i put the ngk plugs in and regaped them and still at like 12.5 to 13

[Sp00ner]

I would suggest asking either Clownhair, or one of the other guys with some hands-on exp with this. I keep giving people the wrong info on this it seems... try this thread, ask there...

http://www.redlineforums.com/forums/...7&page=1&pp=10

Clownhair has been through a few pullies and did some testing and logging, hasn't made it to the dyno yet, he will be this week I THINK, anyway they got more info than me...

I know that the computer/engine management will come into play near redline to some degree. I think I remember them saying that it will bleed some off at redline. Are you making full boost sooner though?

[clownhair]

Yeah you should still make 14 psi without doing anything else. I suggested in the other thread that the Cobal boost guage may be innacurate, seems alot of people are having problems with them reading too little boost. It does flutter towards the end of the rpm range and will begin to lower some of the psi.

[clownhair]

Originally Posted by Sp00ner

Clownhair has been through a few pullies and did some testing and logging, hasn't made it to the dyno yet, he will be this week I THINK

Appointment is friday morning at 8 am.

[AndrewNayr]

pull the hose between the boost control solenoid and the wastegate can. that will eliminate the upper rpm (ie high boost) ECM controls, while still maintaining the bypass for normal operation. Notice 2 hoses at the wastegate, one pulls (vacuum based so normal cruising doesn't use the blower), the other pushes (peak boost pressure control). The solenoid (closed till told to open on high end from what I can tell) will still be hooked up so you won't get a code, it just won't do anything. The peak boost won't be too high cause its a blower, not a turbo. ECM will still fuel properly cause its doing so based on the MAF during wide open (no 02 feed back).

[cobaltssblu]

so u take the one that goes from the waste gate basicly the longer hose

[AndrewNayr]

There are three vacuum lines in the system.

1. From the head to the boost control solenoid - don't touch

2. From the boost control solenoid to the wastegate - pull me

3. From the throttle blade to the wastegate - don't touch

Pull number 2. Its easiest to pull it off of the boost control solenoid, instead of pulling from the wastegate. Pull it off the solenoid and leave it hanging.

The factory injectors can support around 13-14psi before flatlining. The only detrement is that it runs slightly leaner (no risk to the engine, not that lean, maybe 0.4 A/F leaner), which can degrade the life of the catalytic converter in theory, although I have never heard of anyone having any code that was caused by this mod and I know several owners will it this way.

Unless you have a pulley smaller than 82mm, you should be perfectly fine. Realize, though, that the ECM only pulls boost above 5800 rpms (slightly sooner in first), and that's the only area in the rpm range that will be affected. I can tell by watching my boost gauge when the ECM controls the boost. Its rpm based, not pressure based, probably so you don't slam the rev limiter at full boost, till you reach around 15 or 16 psi, at which it will cut in no matter what the rpm is. If you track or drag race the car, you will notice the gains. During normal driving under 5800, the factory boost control is not active, and the car will feel the same regardless of whether or not you have the line undone. If you simply pull the connector off the solenoid, like I did at first, it sets a code on key up, so don't do that. I would highly, highly recommend the shift lights on the steering column, so you can better take advantage of the higher rpm power without tanking the reve limit.

All of this is assuming you are running premium full, which, if you're not, you should be drug out into the street and beaten

If you run 87oct, the ECM will pull spark and you will drop to around 180 hp on a warm day.

Final note, be sure to correct the wiring on the aftercooler pump, if you haven't already (corrected in the factory if you're car was made after 1/1/05 according to the service bullitin). It takes 5 minutes and is a huge help with modified cars.

[tomegun]

So your saying the opposite ?