seb71

Thanks for the very descriptive write up. It will be tremendously helpfull to me as I am about to embark into this project. I purchased a LG longtube header along with a stock Z06 X-pipe, mufflers and tips.

A few stupid questions that i still have:

Will the fact that I will be running LG headers mean that I will NOT be using the factory X-pipe with the vacuum?

Do you need to run all these vacuum lines if you want to have the baffles closed (or open whichever gives you more flow!) all the time?

Thanks to all.

seb71

I got only one stupid question. Great write up and job that's for sure. Here is my dumb question...

Why all this vacuum when it really is not needed; is it only to please your wives whenever they go to the grocery store with your car?

Vettlldo

The purpose of the vacuum source is to keep the valves closed during normal operating conditions. Otherwise, without the vacuum, the springs mounted on the valves pull them open. If you read some other threads about using the Mild-To-Wild wireless switch, there is a lot of drone leaving them open all the time.

TooManyIDs

Fantastic work, thanks for posting.

SunsetOrangeCreations

Why bother putting z06 bi-mode exhaust on if you are only going to leave it open?

Just buy corsas and be done if you want it louder.....

The whole point of the bi mode exhaust is to have the quiet option AND the loud option.....

bub

Looking at the schematic, it looks like a good way to introduce a vacuum leak...modern engines just love vacuum leaks....

bub

With all those connectors, I'm just saying that there is more potential is all...same with NPP as well...perhaps even moreso due to the scale of production anticipated for the NPP vs. Z06...

The connectors look pretty fancy, and are probably idiot proof, but even the best laid plans...

SunsetOrangeCreations

I can agree with that.

The more connectors the greater Chance of leaks.....Thats why I used all the gm parts so at least I was as close to the factory setup as possible.

I thought that you heard of a proven fact that the system leaks.

If there is an issue in the future it can be investigated just like a z06 or a npp exhaust......so far I have not heard of any issues with the vacuum system for the z06/npp mufflers. As more and more are made maybe we will hear about some issues in the future....

EDIT: I decided to pull vacuum on my system with a mityvac just to see how secure it was.. I left it pulled for 3 days to 15" vacuum and when I looked again there was No Loss of vacuum. So there are No Leaks on my system when using the factory tubing.

I guess you could take out all the vac stuff and use some kind of electric actuator instead.

Vettlldo

Yes, the connectors are industrial strength. The OEM vacuum tubing is pretty darn stout as well. It looks like 1/4" tubing with a rubberized black coating on the outside.

SunsetOrangeCreations

I know I have been posting a lot about how I like this mod and it was easy. Well it is easy, just a little involved.

I want to add a little more help for people who may be doing this mod themselves.

There are 5 main GM vac pipes. #1 from the intake maifold to the vac pipe that goes from the engine compartment to the side of the tranny. #2 from the engine compartment to the side of the tranny, #3 from the side of the tranny to the rear under the facia. #4 from the rear pipe to the valve and vac canister, #5 from the valve to the butterflies. These numbers are not what is on the spec sheet they are just the order from front to back.
You should be able to make out all the parts frm the previous posts.

If you use all gm vac tubing, almost all the clips and connectors are already on the car. Once installed it is just like the z06 or npp exhaust minus the bcm computer control of the valves. It looks stock and is very clean.

You will need to remove the tunnel plate when you install the gm vac pipe #2 from the engine compartment to the side of the tranny.

There are two clips along side the torque tube on the body that have a vacant slot to hold the vac pipe. They hold the fuel lines and have a vacant spot. Hmmm...its like gm knew there was going to be something there. Mines an 05 built in 04......

There is also a clip connector next to the drivers side cat on the body that has a vacant spot for the vac pipe as well. I wasnt able to open it though... Its fine without that one.

There is a clip thats right next to the brake booster with a 10mm nut that has a vacant spot for the vac pipe in the engine compartment.

The #1 gm vac pipe with the check valve connects to the rear vac port on the intake manifold and then to the #2 vac pipe that leads to the side of the tranny that you just installed. Its way easier with the fuel rail covers off.
You will need to pop the tab that is sealing the port on the intake. Its hard to get to. Be carefull!


The #3 rear vac pipe runs from the rear facia above the tranny over to the #2 vac pipe that comes from the front. It clips to the fuel line above the tranny.

You can install the vac solenoid and #4 and #5 lines through the rear bumper from underneath with the mufflers out. Feed the line and solenoid up from the bottom in between the bumper foam and rear compartment. Feed the #5 butterfly line up the center between the foam and the rear facia. Its a tight fit...You will have to reach through the rear passenger taillight hole to install the solenoid screw so hopefully your arms are small. If not you may need to remove the rear facia, but I would just get someone who can reach through, its so much easier.

The vac canister can be installed under the passenger cargo area without removing the rear facia.

You should be able to get to the spot to run the wire through without removing the facia as well. Small arms helps out here.

I was able to do the whole job without removing the rear facia.

Wire up however you want to make it work, I like the ultimate exhaust commander to open the circuit at a specified rpm.

If I think of anything else I did, I wil update this post. I know I may be missing something I did but this should set the stage for others to follow.

seb71

Yes, as I said, it was a stupid question! :o

Speaking now of "experience" it does drone between 1300 and 1700 rpm. I am planning on installing the vacuum lines whenever I get a few extra $$ and time!

Here's another stupid question;

Would it be possible to JUST instal vacuum lines (no electrical/electronic switch) and have a manual openning and closing valve that could be mounted perhaps in the glove box?

Thanks.

seb71

I sort of shopped around and Bill says he paid $250 installed, and I saw them for as much as $400 without installation. I paid $375 for some very lightly used ones.

What GM charges for new ones is sort of irrellevant really...

Hope this helps.

SunsetOrangeCreations

You Could do that.... but its really not practical as you would have to run the vacuum from the engine compartment into the cabin and then out of the cabin to the mufflers.

It wasnt too bad to do the gm tubing when the mufflers and tunnel plate were off. While they are on the car its gonna be tough.

It can be done as Bill did his without taking the tunnel plate off, but I believe the mufflers and h pipe were out...not sure.


I am really happy with the setup and would not want to just have them stuck open all the time.

The other thing to look into may be to set up some kind of electric actuator to open and close the valves and skip the vacuum altogether.
It would take some engineering on your part though as nobody has done this yet.

Let us now how it turns out!

seb71

I am with you on not particularly wanting them open all the time. It is nice to be inconspicuous some of the time!

It would not be the end of the world to remove the pipes all the way back from the cats to make way to remove the tunnel plate.

Bill also suggested, after I asked avoiding all these vacuum lines altogether, that I just install a manual choke cable type thing that would hook up to the baffles therefore avoiding the vacuum lines.

I just like doing things right and will probably end up doing it the way you guys did it. Not sure if I am that **** and will probably use generic lines. Can't really see them except if you really look closely... Fit will be fine.

I'll keep you all posted.

seb71

Hey, do you have any idea as to what could be used as an electric actuator?

Secondly, do you know the part number of each OEM vacuum line?

Last but not least, you say that it connects to the exhaust manifold, if I have LG Longtube headers, where would I be connecting the vacuum to?

Thanks.

leres

I keep wondering if you guys could use the factory "exhaust tail pipe flow valve control module." It just needs ground, power and class 2 data. The module goes in a compartment in the very rear of hatch area on the the driver's side. If the connector is not there for the non-LS7 application, you might still be able to pick up LS7 class 2 data from splice pack 208 (located near the passenger floor).

Vettlldo

You must have missed my earlier post shown as 3 separate PDF files. See the first PDF file on this post:

Vettlldo

Good questions. Maybe the 2008's w/NPP will provide more details on the Exhaust valve control module in the GM wiring schematics.

leres

The 2007 factory service manual already has more than enough info. Looking at Vettlldo's parts list, the exhaust module is GM 15296305 and lists for $170.

06C6FVR

Wouldnt it be fairly easy to use an RPM window switch like a nitrous kit uses and have it send to an electronic actuator switch that opens during certain RPM ranges, or maybe set to a full throttle activation switch that it only opens at full throttle? Or even just on an electronic toggle switch. Then you wouldnt have to have any vacuum at all. Just some ideas that might be cheaper.