Bypassing the the bypass valve solenoid.

[MPFab]

Long term update:
I have noticed the amount of oil present in the charger tubes has been reduced DRAMATICALLY from doing this mod. Before doing this, I would have oil present all the way up to the throttle body and standing oil in the intercooler and lower charge pipes. I pulled the lower charge pipe off yesterday and noticed only a bit of oil around the rolled bead on the end of the tube. ZERO oil present in the tube itself. This is after a recent track day too.

The factory employs a solenoid to control the function of the bypass valve. This is a 3 port solenoid with one port connected to the intake manifold, one port connected to the bypass valve, and one port connected to a vacuum chamber located on the bottom of the intake runners. This chamber is fed a vacuum signal through a one-way valve also known as a check valve. This check valve ensures that the chamber never sees boost. In doing this, the ECM can utilize the stored vacuum in the chamber to open the bypass valve when it sees fit. The solenoid is also cycled during WOT. This keeps a portion of the boost signal from ever getting to the bypass valve which mean it leaks boost. Neither of these functions is conducive to performance.

Without getting into a boring-ass back story of how I arrived here, let me just explain what this mod does for performance.

The ECM can no longer open the BPV to reign in trq production.
When you put the pedal to the proverbial metal, you don't have to worry about some or all of your boost pressure being released because of conservative "torque management" protocols GM put in place.
The BPV gets 100% of the boost signal needed to ensure the valve stays shut.
This means that power is not "softened" because a portion of the pressure is leaking past the valve.
Power is now is now immediate, and consistent.


*PHOTOBUCKET IS NO LONGER FREE AND ALL THE IMAGES I WAS STORING THERE ARE NO LONGER AVAILABLE TO SHARE HERE.*
I will rectify this as soon as possible. There are diagrams in the thread that other have made for reference


Here is what's needed:
5/32" hose splice
5/32" vac. cap
3"-4" of 1/8" or 5/32" vac. hose
Either will work. 1/8" will take more effort to get on the intake manifold, but this also means less chance of it blowing off since the intake manifold fitting isn't barbed.

Here is what needs to be done to eliminate the ECM from raining on your performance parade...

BTW, you're going to focus all your attention on the passenger side of the intake manifold. Look for landmarks in the photos such as the alternator or the fuel rail to help you.

If anyone experiences anything weird or contrary to this post, please reply in this thread.

 

[Yosemite Sam]

Got it!! :banana:

 

[crazymind]

Sweet!! I know what I'm doing tomorrow

Sent from my SGH-T999L using Tapatalk

 

[cndctrdj]

Subd for results

 

[Hoody32]

Will this mod improve the feeling when at WOT, it seems like the car is being held back at times.

 

[Sonic_Boost]

These last few are a bit confusing. I'm hoping once i attempt this and i'm looking at it i will understand.

 

[law242]

Marking this so I can come back to it

 

[MPFab]

These last few are a bit confusing. I'm hoping once i attempt this and i'm looking at it i will understand.

Could you elaborate? I've been all over this part of the car and this could have influenced how I wrote the directions. I was trying to make it very simple to follow, but it could easily be confusing for those of you who've never even looked at that part of the engine.

 

[sx sonic]

Nice write up and great find. This is a rather easy mod once you find the lines, takes about 10 mins if you know what to do, and do it my way.

Better yet is the results, after some cursory testing (roads have been bad lately)I've found this mod to make more power throughout the rev range. Sometimes it wasn't much but there were a number of points it was making upwards of 10hp over my other runs w/o this mod. Note that I still want to do some testing before officially stating its gains.

As an added bonus the BPV noise is more crisp, almost like a bark.

Also another option for plumbing this in, is to buy 3ft of 5/32" vacuum hose and run it from the vacuum fitting on the passenger side of the manifold to the BPV and plugging the 2 open lines (black/green line at manifold and old line to BPV).

This way is super easy and can be done without getting under the car or removing anything. I couldn't get the hose off the barb shown in pic 5 hence this method.
-Instead I took off the line shown in the last pic with a long screwdriver (it can be seen on the lower passenger side corner of the mani).
-I then hooked up my 5/32" vacuum line and ran it along the old line over the valve cover and to the BPV. The BPV barb is a size bigger but applying some lube and lots of wiggling will get the line on.
-Block off the open lines and call it a day.

Just another way to get this done.

 

[NewZJ]

Looks good to me. I'm 1900 miles from my sonic but I've got a mental image of the area and have a good idea of what to do

The explanation of the system helps me understand what I'm doing, the pictures give me the visual of what to do.
Fantastic.

 

[Sonic_Boost]

I think it was the whole intake manifold part, and how in the picture it looks like its off so that threw me off. What did you use to cap the solenoid and hose?

So unless i'm missing something then whats happening is, the bov hose is getting swapped from the solenoid into the intake manifold and the hose its replacing it being capped and so is the solenoid? Please correct me if i'm wrong, just trying to sort this out.

 

[sx sonic]

Could you elaborate? I've been all over this part of the car and this could have influenced how I wrote the directions. I was trying to make it very simple to follow, but it could easily be confusing for those of you who've never even looked at that part of the engine.

I think if you included a location on the pics it would help. Pic #3 for example could be simpler if the top of the picture had "back of engine bay" and the left side had "passenger side". I think something like that would help orient DIYers as to where they're looking at in the engine bay.
And your last pic add something like "as viewed from under the car".


From up top I had to spend some time finding the lines and I've had the intake manifold out at one time and know what I'm looking for, sort of. It's tricky finding everything the 1st time so every little hint helps.

 

[law242]

Now question, the line you disconnected to the solenoid, do you plug that as well or do you leave it be?

 

[MPFab]

I think if you included a location on the pics it would help. Pic #3 for example could be simpler if the top of the picture had "back of engine bay" and the left side had "passenger side". I think something like that would help orient DIYers as to where they're looking at in the engine bay.
And your last pic add something like "as viewed from under the car".


From up top I had to spend some time finding the lines and I've had the intake manifold out at one time and know what I'm looking for, sort of. It's tricky finding everything the 1st time so every little hint helps.

Good input. I thought about an engine bay shot to orient people as to where all this was going down. Headings for the photos will definitely help.
The way you mentioned doing this mod in your first post was how I instructed everyone testing it to do it. It's easier to explain textually as removing two hoses from their locations, plugging those hoses, and running a new, single hose to connect those locations together. Both ways work well. Running a new hose is just not as clean as using the factory line.
The way I've described is equally as simple as long as you can get the BPV hose off the solenoid..
Just to clarify, my way doesn't require getting under the car or removing anything either. The pic of the intake manifold off the car was provided by Preloader(Thanks Pre!), and the undercar view was taken to help another tester's understanding of what was happening. The car was on the lift so it made it easy.

Now question, the line you disconnected to the solenoid, do you plug that as well or do you leave it be?

Look at the last step. It's taken from under the car. You can see the blk/grn hose has a stainless bolt plugging it.

 

[MPFab]

So unless i'm missing something then whats happening is, the bov hose is getting swapped from the solenoid into the intake manifold and the hose its replacing it being capped and so is the solenoid? Please correct me if i'm wrong, just trying to sort this out.

BINGO!!
You can buy small rubber caps at any auto parts store to put over the open solenoid port. Typically they are found in the "HELP" section. It's often a rotisserie of small packaged parts.
The hose was plugged with a 4mm bolt

BTW, the hose splice will be found in the same section.

 

[sx sonic]

Holy views Batman, this thread is jammin! I think you found the mod of the year MPFab .

The revised captions are a definite improvement for anyone trying to find these lines for the 1st time.

I forgot to ask, did you get any before and after dyno results with this mod?

 

[sonichead94]

so BPV sounds more crisp? what about forge bov?

 

[Preloader]

I bypassed my bypass so now I can boost while I spool.

 

[MPFab]

Holy views Batman, this thread is jammin! I think you found the mod of the year MPFab .

The revised captions are a definite improvement for anyone trying to find these lines for the 1st time.

I forgot to ask, did you get any before and after dyno results with this mod?

I'm waiting to get the new clutch installed before heading back to the dyno. After doing this mod, the stock clutch now intermittently slips in 3rd....

I bypassed my bypass so now I can boost while I spool.

Holy sh*t that's funny!

 

[NewZJ]

I'm waiting to get the new clutch installed before heading back to the dyno. After doing this mod, the stock clutch now intermittently slips in 3rd....

You better hurry up with the clutch kit