dmanrob

you should really just buy an intake and forge diverter valve (closed loop). It will still give you some sound as it blows back into the system, and will be the proper setup for your car.

germanautos

http://jettajunkie.com/vw-jetta/show...ing-Jetta-1.8T

just did this on my 1.8T MKIV Jetta. Hope this helps your questions.

Bozodeluxe

I got the "silly noise" that you might be looking for by installing a K&N Apollo cold air intake. I wasn't doing it for the blow off noise, but got it after the install, some people like it though....

Alos, I would love to get a self adjusting/healing ECU if someone knows where they sell them ;-)

jjt1234

Interesting. I have a Pop Off Valve installed on my 2002 TT and it sounds incredibly cool. I do have a cold air intake. First time I ever heard of the car possibly running rich on de-acceleration. I would ask however, are these POV adjustable? It seems over the last few months the sound isn't as distinct, or as loud as when I first started driving the car. But I love the way it sound. Of course the exhaust system only adds to the excitement!!

Aston Richardson

That's correct

Without getting into the intimacies of the Ideal Gas Law, basic mass air flow systems meter the airflow after it enters the intake system, measuring volume and density so the ECU can calculate fueling requirements. There are two types of mass air flow (MAF) sensors: a vane meter that uses a trap door mechanism to ascertain flow and the modern, more popular hot wire or hot film type. Hot style set-ups use a heated sensing element warmed to a fixed temperature. When air flows past the element is cooled, the sensor works to maintain the element’s base temperature, and the current needed to do so is how the sensor determines airflow. The amount of current being used is converted into a voltage signal, which the ECU infuses into its fuel calculations.
There are two types of mass air flow (MAF) sensors: a vane meter that uses a trap door mechanism to ascertain flow and the modern, more popular hot wire or hot film type. Hot style set-ups use a heated sensing element warmed to a fixed temperature. When air flows past the element is cooled, the sensor works to maintain the element’s base temperature, and the current needed to do so is how the sensor determines airflow.
A turbocharged MAF-controlled engine runs a recirculating BOV because the system is a self-contained closed loop and the computer has determined its fueling strategy based on the flow. Re-inserting the boost into the system will not upset engine operation. Running a vented BOV changes the airflow (by venting it out of the system) AFTER the computer has decided its fuel parameters. The result is a hiccuping horror show of an engine that will barely run.
Speed density systems are more predictive in their approach to engine control. The major components of a speed density system are the Intake Air Temperature sensor (IAT) and Manifold Absolute Pressure sensor (MAP).
Engine speed, throttle position, and coolant temperature are other parameters that go into speed density calculations. An oxygen sensor mounted in the exhaust system relates combustion efficiency to the computer after the fact. The ECU takes all the data, readings, and measurements and selects one of many pre-programmed tables that represent a volumetric efficiency value of the engine. The table has a corresponding fuel table that is employed to run the engine. Since this system is not a closed-loop, pressurized design, losing or venting pressure to atmosphere will not impact performance so it can run either style of BOV.

Aston Richardson

Some are adjustable, infact those types are best for Audi tt, as you adjust the bov to shut and close the loop b4 the car gets to the icv (idle control valve) stops the car trying to settle its self constantly in what uses more fule

J. Patterson