As I am planning on returning to stock exhaust, I am considering a flapper mod. I do have a few questions about things I read in this thread:
1- What is this TampaVW mod everyone talks about?
2- Why can we not use an OEM switch instead of the custom built switch?
3- Can the two way switch be wired to Stock/Always Open, or does it have to be Always Open/Always Closed?
Thanks for your hard work on this topic!
- remove stock resonator
- replace with Magnaflow 12" resonator
- remove the Magnaflow 12" resonator, cut 6" out of the middle of it, weld it all back together and re-install
- circle the car with a dead chicken.....
For reasons I've never got to the bottom of, you're not supposed to start with a Magnaflow 6" resonator....
- start with a 'cold' car
- lay under car, look up at where exhaust tips meet muffler
- ease the 1/4" pneumatic hose off of the pneumatic servo that's attached to the right tip/pipe.
- put an appropriate sized screw in the loose hose end
It's open for me. I think I've heard of a few folks whose flapper wasn't open, and needed to be jiggered somehow.
I plugged it to avoid codes, but it might not be necessary.
You plug the hose so nothing can get into the vacuum line.
As far as having Stock/Always open vs my current setup of Always Closed/Always Open I have looked into it a bit and it should be doable. I will be redoing the wiring once it warms up. I plan on tearing apart some of the interior paneling and tracing where the wires are going so everything can be wired under the dash instead of running wires into the hatch.
This won't happen for probably a month or two. When I do that I will research some more how to wire a switch to be Stock Mode/Always Open.
A custom switch isn't necessary to do this, but a custom relay is. If I can find an electrical engineer to look at the relay maybe it could be easily made by someone with the knowledge.
When control wire to vaccum solenoid is floating, flapper is open, so all you need to do is put a switch between ECU and solenoid.
When switch is closed, stock behavior.
When switch is open, flapper is always open.
You should also add the 1k pullup resistor to avoid triggering error codes.
(I have not tried without resistor though)
Maybe I interpreted your diagram wrong.
So you are saying to run a diode from 12v to ecu line and have the switch inline with the ecu line?
I'm also trying to find out if UM software disables the flapper via ECU because mine with wiring back to stock no longer does anything and is open 100%.
The fix consists of two parts only:
1) Put a switch inline on ECU control wire (brown/lilac)
When switch is open, flapper is disabled/open/loud.
When switch is closed, control signal is passed through and we get "stock mode"
2) To avoid throwing error codes when we open switch, connect a 1k resistor from ECU control wire to 12V. The 12V can be taken from anywhere, but the red/blue cable is close and has 12V.