Thanks to member Chomper for the NPP mufflers - good guy!

Added the mufflers to my '09 Z51. Was running them open full time. The car is completely stock.

I finally got around to having the time to install an exhaust controller. I didn't want to rely on engine vacuum, because:

1. If something went wrong with the vacuum lines, fittings, or controller components - I might get a vacuum leak, and that would suck to have to chase around.
2. I didn't want to try to break off that little tab on the back of the intake.
3. I didn't want to tap into the brake booster.

Solution? Well, the engine is just a big vacuum pump. So I found a small vacuum pump. A Dorman pump intended for Ford Diesel trucks.

Got everything from Amazon.com:

- The Dorman pump pulls enough inches of Hg to close the exhaust valve actuators (and it shuts off automatically once it reaches its setpoint ~12 to 15 inches of Hg, according to Dorman tech support)!

- Used an AC/Delco turbo wastegate 3-way solenoid to control the system. When it has power, vacuum flows through it. When it loses power, it dumps the line to atmosphere (thus opening the exhaust) Used a new MAC valve and 1/8" NPT fittings. It is designed for constant duty cycle and won't overheat like the turbo solenoid

- Got a pigtail wire harnesses for the Dorman pump

- Vacuum tubing and a little tee (multipack because it was so cheap)

- Standard add-a-fuse (tapped into the cruise control fuse since I was already using the heat seater fuse for my Valentine One radar detector)

- Wire, a heavy duty switch I thought looked cool and feels solid, and a little project box with flanges so I could use an existing under-the-dash screw to avoid drilling holes

- Industrial strength velcro from Lowes to attach the pump and solenoid to the inside of the trunk cavity (behind the carpet)

Here are most of the parts:



edit: Here is the new valve I have sourced (next to the ACDelco solenoid that is not up to the task!):



Here's my cool switch box:



Here's where I put the switch, so I can reach down with my left hand whenever I want (used an existing dash screw and a washer to get the appropriate standoff). Used a coat hanger to pass the wire from this location, over the tunnel, to the passenger fuse panel location. "Off" is exhaust-open. "On" is exhaust-closed:



Here's the pump and the valve wired together, getting power from the add-a-fuse and ground connection from the passenger fuse panel, and with the vacuum lines connected to the proper ports. Interesting to note is that the pigtail for the Dorman pump has 4 wires, but the pump only has 2 wire posts. So, I heatshrunk and zip tied the yellow and blue wire away. In most connections, I used heat-shrinkable crimp detachable plugs (you can get those at Autozone) so I can easily remove wiring if needed:



Put some Velcro - brand-name stuff; it's the best - on the pump and valve and on the interior rear trunk wall underneath the carpet:




(this old photo shows the ACDelco solenoid instead; I put the new valve in the same place):



The vacuum tubing goes from each muffler to a tee, to a line, and that lines comes up through the bottom of the bumper assembly to the inside of the bumper into the wall cavity through a little hole that is above some pre-existing green wire that has a grommet. Above that green wire and grommet, if you peel back some little rubbery tape, there is an existing hole. There is another one on the other side too. I made that hole slighty bigger with a drill, and fed the vacuum tube through it. Then the tubing connects to the solenoid, then from the solenoid to the pump.

The solenoid is in-between the pump and the mufflers, because although the pump shuts off automatically when its full vacuum is achieved, if you cut the power the the pump, it will not release vacuum. It must have an internal check valve. I didn't want to modify the pump because it doesn't look very easy to get into.... so using the solenoid to vent the line to atmosphere works well.

To me, this setup is much better than the current "NPP in a box" because:

1. No engine vacuum line
2. No remote control
3. Switch is reachable by your hand instead of in the "dead pedal" location
4. Components are easily replaceable if they fail
5. DIY is neat

Back in "the day" I guess (like maybe almost 10 years ago) it seems the "NPP in a Box" guy's product actually used a vacuum pump. I read on the forum on some old post before I started this project that he stopped using the vacuum pump because he couldn't source them anymore. Apparently the one he was using was really tiny and used in military applications or something. Edit: actually, he may have been using a medical device for asthma patients. Regardless.... All I know is the pump that I used is very common, and available everywhere. It's like $50.

When I turn the system on, the pump turns on and makes noise for a few seconds. The exhaust valves then fully close, and the pump turns off automatically because it has reached ~12 to 15 inHg. When I turn the system off, air dumps through the solenoid and exhaust is back to "loud" and nothing is receiving power.

The cruise-control fuse is ignition switchable (like the seat heater fuse). Therefore, the system draws no power unless the car is on.

I hope this helps someone. I did A LOT of searching to plan this project. Camaro forums and Corvette forums helped. The AC/Delco solenoid operation was gleaned from the Camaro guys and some Volvo guys- I'll have to tell them it's unreliable if they haven't already figured that out....

This is awesome! Now I can have it quiet on long road trips (the drone with NPP in the full open position is annoying as hell to me).

Happy 4th!

 

This is an awesome write-up. I might end up doing it this way myself. Thanks for sharing!

 

No problem, bro. I searched forever for all the info- I'm hoping this helps someone.

You could also use a relay with the switch, but the switch I used is rated to 20A so I'm not too worried about it.

 

Just out of curiosity, how noisy is that pump

 

Noisy enough to hear it in a quiet cabin during the 2 to 3 seconds it runs to close the valves. It shuts off automatically after those few seconds.

 

You could also mount it outside the cabin (behind the tail lights) and that would be quieter for those few seconds it runs. You could insulate it too.

 

I guess a couple seconds isn't too bad. Must be a strong little pump

 

It's one of the biggest ones I have seen at the price point (~$50). The auto shut-off is the big plus. There are some much cheaper ones available online that are much smaller that could probably do the job, but you would have to regulate them somehow.

 

I really liked your approach to this control. What solenoid did you use. Could you provide the part number for the AC-DC Delco valve. Thanks

 

Drove the car around all day today with the new system- works flawlessly.

One interesting thing is that if your garage is cool, and you activate the system before setting off on a drive (in the 105 degree Texas heat), the pump may turn on again for a second or two a couple of times at the start of the drive- this must be because the air in the lines is heating up (or the lines themselves) so vacuum is reduced (pressure is increased). As everything reaches equilibrium, the pump won't turn on again the whole drive. If you had the radio on or somethin, you probably wouldn't notice that second or two run.

Pretty neat system so far. I'm pleased with its simplicity. I guess to prevent the above you could add a vacuum reservoir, but that would probably increase the time the pump would run in the beginning. I say it's fine the way it is.

Starting on a drive in quiet mode with the car parked outside first resulted in no secondary pump switch-ons at all, that I noticed.

 

Parts list:

ACDelco PT2830 Pigtail for the solenoid
ACDelco 214-474 solenoid - DO NOT USE THIS PART - IT WILL FAIL. NOT DESIGNED FOR DUTY CYCLE.
Hammond 1551RFLBK project box
Heavy Duty Toggle Switch - SPST On/Off Type
RGBSIGHT 40FT 18 Gauge Single Color LED Strip Extension Cable
11Pc Auto Trim Door Panel Window Molding Upholstery Clip Removal Tool Kit (bought this for the hell of it - useful tools for tons of things)
Gates 27041 Windshield Washer and Vacuum Hose
Qiorange 12v Car Add-a-circuit Fuse TAP Adapter Mini ATM APM Blade Fuse Holder Pack of 5
APDTY 112687 Wiring Harness Pigtail Connector for pump
Dorman 47329 Vacuum Tubing Connector
Dorman 904-214 Mechanical Vacuum Pump for Ford Truck

note: really should use a relay with your switch unless you use a heavy duty switch (the one I got is rated for 20A, so no relay needed for this application)

 

Thanks for the quick reply. I am currently using the npp in a box but it has quit working.

 

No problem, bro.

 

Great writeup , wish I saw this before I cut my hands up trying to get them to go into places that human hands should not try to go to break off the tip of that darn nipple......

Dave

 

I didn't even try to get to the back of the intake. After reading people's experiences, and that some guy actually broke off the nipple, I was like "alright, looks like I would need to remove the intake to even get to the damn connection - **** that. And what about vacuum leaks in the future?" Vacuum leaks on an engine are bad. Vacuum leaks isolated to ONLY the exhaust valves with my system..... not really worried about it.

 

Let me tell you , I lost count of how many times I shouted out obscene words.......

On my last try, before I was going to give up and remove the manifold. the cap on the nipple popped off .....

But my hands were still swollen and cut up from jamming them into that little space between the firewall and the manifold.

If this was posted back when I converted , there would be no question in my mind how I would have went !!

Again , Nice Job !

Dave

 

edit: my below explanation is wrong. The solenoid was dying. It is now dead (works but has a leak). RIP solenoid. Now looking for a different part (per next post).



To update my experience with using the system more- it's hot as **** here in South Texas, so the pump will turn on every so often until the lines stop heating up (the first part of the drive) as I mentioned before. It makes sense from a thermodynamics perspective, of course. It may be that adding a vacuum reservoir in the line would prevent that. I don't think I'm going to, because I don't care that much and the pump turning on every so often only occurs at the start of trips in high heat differential between air entering the pump in the cabin and vacuum line temperature. I didn't measure the total length of vacuum line I used.... but that length multiplied by the small internal cross-sectional area of the tubing would be the volume of the current "reservoir." Adding an actual reservoir would increase the volume significantly, and placement of the reservoir would affect its heat exposure.

 

Do NOT use the ACDelco solenoid I used above. The duty cycle damages it and causes a leak.

I thought a 3 port 2-way solenoid was a slick way to do this. I picked the wrong part. Now the pump will cycle on every 15 seconds because I killed the solenoid.

There's a reason the Subaru guys stopped using that ACDelco unit.... (I know this NOW)

 

High quality Mac valve on the way. Will receive late next week. Part number 35A-AAA-DDBA-1BA

$20 from the Texas Mac distributor. Mac makes good valves. You can also find this valve online. Talking with the manufacturer, it will have no problem being left on for long periods of time!

I shall return the ACDELCO solenoid to Amazon. Twice the price of the Mac valve.... none of the performance.

 

New solenoid valve came today! Just installed it and it works great! Much better solution than the ACDelco unit. Updated original post to reflect part change. Note that I have a filter on order for the "3" port on the solenoid, which relieves vacuum pressure from the line when it de-energizes. $4 from Amazon