Ok I just ordered these DV's for my 996 Turbo..

http://www.awe-tuning.com/pages/shar...IL=BaileyValve

In this link it says..

What is a diverter valve? A diverter valve (DV) is a pathway for boost when it is not being used by your engine. Whenever the throttle body is closed, like during shifts or decelleration, the boost needs an escape route. If the boost cannot escape during these times, it can back up and cause shocks to the turbos. These shocks will stall the turbos, slowing boost production upon re-acceleration (turbo lag). Even worse, these shocks can cause damage to the turbos. The diverter valves' job is to open when the throttle body is closing or closed, and reroute the boost to the low pressure intake side of the turbos, where it can do no harm.


Now am I crazy or is a DV another type of Blow off Valve?

Could you use a BOV instead of a DV?

Or is the DV different?

Sorry for the noob questions..

 

The bold part is the difference between a BOV and DV. The BOV vents to the air, the DV puts it back into the intake tract (pre-turbo compressor).
The problem with using a BOV instead of a DV is that the diverted air has arleady been metered by the MAF. The ECU expects that volume of air to be in the intake tract and will act accordingly, adding the appropriate amount of fuel. If that air isn't there (say, for example, because a BOV has shot it out into your engine bay), it will add too much fuel for too little air and you'll get a rich condition. After awhile, this can lead to idle problems, etc. as the car attempts to adapt to this situation.

Stick with DVs, the PSSHH sound isn't worth it.

 

I think what BavBoy meant was: is a diverter valve the same as a recirculating valve?

A BOV is the same as a recirculating/diverter valve except it vents to the atmosphere rather than back into the intake manifold. Why the p-crew doesnt like BOVs is terra incognita to me.

 

Awsome answer! Thanks

 

But dont almost all turbo cars have MAF.. They still use BOV's?

 

Yes almost every [respectable] car on the road has a MAF... performance cars for sure.

"An air flow meter, also know as air consumption meter, is a device that measures how much air is flowing through a tube. It does not measure the volume of the air passing through the tube, it measures the amount of mass flowing through the device in a defined time segment. Thus air flow meters are simply an application of mass flow meters for a special medium."

source: http://en.wikipedia.org/wiki/Mass_air_flow_sensor

 

There has got to be a valid reson people dont use BOV's in 996 TT's... I want the answer.

 

You got your answer in post #2.

 

Are we positive about this..? All turbo cars have MAF, and ECU to read everything.. I have seen almost every turbo car use a BOV. I am yet to see a Porsche with one. What makes the 996 different?

 

nothing in post #2 applies to any other turbocharged car.. why would it apply to a porsche?

 

not all turbo cars use MAF, 1jzgte twin turbo supra (JZA70/Soarer jzz30) motors use a MAP sensor.
i believe MAF sensor engines shouldnt run vented BOV because of the reason stated in Post #2, Map sensored vehicles can run vented BOV becuase the vented air isnt accounted for until it reaches the intake manifold.
hope that helps a bit

 

VG30DETT, SR20DET, and RB26DETT all use MAFs and BOVs are appreciated with those engines... next!

 

Does anyone use a BOV on there 996? Chime in.

Ricer or not. I like the Woooosh sound.

 

Oh yeah, did Wikipedia say so?

 

no, your mother whispered it in my ear as i left her casa this morning.