[s-cars] N75 WGFV

[FvAMI at aol.com]

In a message dated 10/15/04 12:10:35 PM Pacific Daylight Time, ray at s-cars.org 
writes:


> All,
> 
> Jim's description of the "K" valve is quite accurate.
> 
> For starters, the "K" valve to which he refers is the Wastegate Frequency
> Solenoid, commonly referred to as the Wastegate Frequency Valve.  The "K"
> refers to the suffix "K" in the VAG part number.  Those of you that have a
> US version of ETKA will not find 034 906 283 K in your catalog, because the
> solenoid was designed by Eaton for use almost exclusively with the RS2
> turbo.  The difference between the 'K' valve and the stock 'H' valve (034
> 906 283 H) is the duty cycle of the solenoid.
> 
> The WGFV measures boost pressure relieved by the wastegate, and reports the
> same to the ECU.  The WGFV's ability to quickly and accurately meter
> relieved excess boost pressure ensures that the ECU does not detect
> prolonged overboost or boost spikes, to which the ECU responds by dialing
> back timing.  A faster duty cycle can more quickly and accurately "detect"
> and report boost spikes to the ECU, while reducing the potential for the
> same created by the increased charge air pressure created by the RS2 turbo.
> 
> I know of only one US vendor for the "K" valve.  $90 through TJM Motorsport.
> www.tjmmotorsport.com.
> 
> Ray
> 
> 

The duty cycle is controlled by the ECU which also has some adaptation (very 
slow adaptation) based on pressure transducer feedback. The orifices may be 
such that these are slightly larger or smaller ... switch a little faster or 
slower ... be a little more robust ... or marketing hype to sell a few more 
solenoids ... if you were/are seeing an overboost situation that fixed itself by 
changing the solenoid valve ... most likely your valve is/was sticking or you 
had an air leak running between the valve and the wastegate.

Best regards,
Feico van der Laan