mechanically fool it for more boost? Free....

**97grandprix1** · 04-14-2014

I've been told you can partially plug something, or switch where vacuum lines go, something, etc. Can anyone confirm or deny this claim? short of the story is this guy I know did some mod to my car and it was great, full boost on the guage, it pulled great! I let it be known that I need to know the mod or I don't want it on my car and during a p*ss break something got reversed. Now the car runs like it did last week when I bought it.... the temptation of free boost has me wired...help!

**industrialfish** · 04-14-2014

It works by blocking the Boost Bypass Solenoid. The problem is, now your car can't vent boost when the TCS comes on, or when in reverse, or any other situation when the computer pulls boost for any reason.

**Z34Phoenix** · 04-14-2014

the solenoid is junk. the BBV however should not be messed with. it is there to save gas an limit boost when it is not needed. like lower throttle inputs. when you step on the car or the demand for air is greater it automatically closes and allows boost.

**97grandprix1** · 04-15-2014

thanks for the info, is the digital boost guage in these cars somewhat accurate? I'm getting maybe 1/2 boost, maybe on a cool morning 5/8. all description is based on having it matted! I'm on the hunt for a 3.5" pulley too....what size is stock?

**REDCRAPGP** · 04-15-2014

You need to do some more research you can't just throw on a 3.5 and think everything will be fine your going to destroy your motor. Stock is a 3.8 you need mods to safely drop pulley sizes.

**coolone** · 04-15-2014

There's no shortcuts and no tricks, plain and simple!
If you want performance there's a golden rule!

CHEAP
FAST
RELIABLE

You can ONLY have two of those three at any time...

You want cheap, sure, it's there for you, but it won't be fast if you want it to last!
You want it fast and to last, it won't be cheap!
If you wanna be cheap and fast, it won't last!

Make your choice and choose wisely!
: )

**97grandprix1** · 04-16-2014

ya, reliable is the way. My car has aftermarket exhaust and a cone filter...not much I know. Before I joined this site my research led me to believe some cars could go as low as a 3.4 pulley without any trouble. You are the experts and that's why I'm here. What else do I need. I want to stay bullet proof, but its not that fast... not looking to lose to a focus svt....good thing I didn't notice him taunting me until it was too late

phoenix- the solenoid is junk? please elaborate, mines junk or get rid of it altogether?

if a 3.5" wont work I'm open to suggestion!

**bennyboy131** · 04-16-2014

intercoolers are cool, but expensive. if it were me, i would do headers, downpipe, rockers, a tune, and an i/c. but thats me and thats what my final build will be. start with headers and downpipe. thats gonna help with reliability with the 3.5" pulley

**industrialfish** · 04-16-2014

Originally Posted by 97grandprix1

the solenoid is junk? please elaborate, mines junk or get rid of it altogether?

It's broken and not closing all the way, thus leaking boost. So plugging it stops it from venting boost, which is a band-aid but can mess things up if your engine NEEDS to vent boost. It's a $43 part, with one bolt, one connector and two small hoses. 10 minutes to swap out.

**97grandprix1** · 04-16-2014

Lets approach this from the other direction. I'm not into headers. This car has a high flow cat to 3" to dual 2.5". the next go fast $100 bill should go to???

If I end up taking the ex manifolds off I will definitely do any port matching/enlarging of the runners if possible

**REDCRAPGP** · 04-16-2014

Downpipe and you really need to go and study the safely modding thread

**97grandprix1** · 04-16-2014

I just looked around, not seeing a thread titled like your description. The thread I did read suggested plugs/wires/u bend delete. where might I find a photo or better description of this u bend. This car was owned by an enthusiast so the u bend may be done already, Plugs and wires have been

**Bakerdd** · 04-16-2014

http://www.grandprixforums.net/threa...ding-Your-3800!

**l67ss** · 04-16-2014

Look under the car behind the cat, the u bend is VERY obvious

**tomtom123** · 04-16-2014

If there is a 3" downpipe with high flowing cat, your u-bend is most likey gone. My 2.5" downpipe from ZZP got rid of my u-bend. I am going to headers now. Keeps knock down even more. If you are only building about half the boost, replace the boost bypass solenoid. Mine went bad and I was only producing half boost as well. You will notice a difference after replacing that. I ran with mine plugged off for about a month or two and now I have a new engine because I blew piston 3 and chipped piston 1 pretty good. Not saying that for sure is what did me in, but after plugging it off and doing a few wot runs I started getting some codes saying I was running lean which will definitely cause chipped pistons. Main issue is knock. Do the exhaust mods and save yourself the headache of combating knock before modding your car too deeply. Tune up first. Fluid changes. Read that modding thread a few times. I have and I learned a lot from it!!

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**97grandprix1** · 04-17-2014

NICE! That thread is B**CH*N ! I guess my last questions are: does an aftermarket front ex manifold dump down differently or could I route mine different to avoid a header ? Did the factory do a poor job of balancing the ex flow of the engine and the necessity is achieving that balance?

I know a great exhaust guy, for cheap I could have the pipe improved

The moral of the story is I fricken hate headers!

**97grandprix1** · 04-17-2014

I also talked to the guy I purchased the car from today, apparently it sat for 3 months while he drove his new car....took a while to come to terms with the idea of parting ways. I know sitting is bad for anything, and to my surprise the solenoid that was giving me trouble starting doin its job! Petal mashed on the on ramp, the boost guage went from 1/2 or better to full and away we went (no children in the car) after repeated attempts to find fault I had a great time, guess I should pick that solenoid up for a spare anyways though

**tomtom123** · 04-18-2014

I believe the biggest problem with the stock manifolds are the diameter and the amount of exhaust flowing through them. Idk where you can get that information, but basically you have 3 openings with like ?1.89"? Piping or something like that. I read on here somewhere a long time ago about the manifold pipe sizing and basically the front manifold and u-bend are the most restrictive pieces on our exhausts. Next is rear manifold. I guess front plog is best route other than headers for flow.

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**97grandprix1** · 04-18-2014

right, that was the basis for the front valve cover recall. Too much heat in front, i'll go to work with a burr bit and a cartridge roll. Has anyone looped the exhaust under? Ya heat rises but seems that pulling that heat away from where its at on top would have benefits.

**97grandprix1** · 04-18-2014

I should mention my build (always ending with reliable for the family) will end up stomping newer 4-6 cyl's, svt's and rt's. Not heading down the drag strip.

I'm liking this S/C stuff...just really looking to mash it and see full boost until I let off regardless of initial or top speed, say 6-7lbs super consistent. Is that on the table?