[urq] WX, Wastegates testting.

[Ed Torres]

Cool,
I think my WG is fine.  I wasn't sure why it didn't hold pressure on the bottom chamber....
Top chamber does hold psi...I just need to keep backing the WG hex-bolt back until stops cutting fuel.


 

~~~~~~~~~ __o 
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~~~~~ (    )  /  (    )  ™
Ed Torres
FA901038 UrQuattro
Norwalk Ct 06855
RIDE & DRIVE SAFE & SMOOTH!!  


 

> Date: Wed, 20 Oct 2010 13:20:50 -0700
> From: urq at pacbell.net
> To: urq at audifans.com
> Subject: Re: [urq] WX, Wastegates testting.
> 
> ... I read that the OP was applying pressure to the bottom of the WG ... this IS 
> exactly the way it is intended to work.  I think you are thinking about the 
> fitting on the cap ... but even there you should be able to operate the 
> wastegate ... you'd need vacuum rather than pressure to open though.  I can't 
> imagine what mechanism applying pressure/vacuum to the upper chamber would have 
> on possible damage to the WG ... all the diaphragm operates on is the difference 
> in pressure between the top and bottom chambers ... biased by the WG spring of 
> course.
> 
> You should not expect the lower chamber of the WG to hold pressure, but if you 
> suspect the diaphragm is leaking you can apply pressure or vacuum to the fitting 
> on the cap, and it should hold whatever pressure you apply.  
> 
> 
> It is a fairly simple matter to tweak boost on the WX.  Most of the older cars 
> have the adjustable spring perch in the WG cap, which can be used for minor 
> tweaking.  Another thing you can do to "stiffen" the WG spring is to attach a 
> closed length of hose to the WG cap ... a longer hose gives a weaker spring.  I 
> have an adjustable pressure regulator plumbed into the fitting on the cap, which 
> is probably a better way than monkeying around with hose lengths.  If you want 
> more info on this do a search on Schrapnell, or is it Schrappnell in the 
> archives.  
> 
> 
> Steve Buchholz
> 
> 
> 
> ________________________________
> 
> Sent: Wed, October 20, 2010 8:17:08 AM
> Subject: Re: [urq] WX, Wastegates testting.
> 
> -----Original Message-----
> From: Ed Torres 
> Sent: Wed, Oct 20, 2010 8:44 am
> Subject: [urq] WX, Wastegates testting.
> 
> Hi Guys,
> 
> quick question...on wastegate:
> I am trying to set my WG to open at 14psi...
> I put air pressure thru the bonjo bolt below of the WG but doesnot hold pressure 
> 
> The diaframe is good since, I checked no visual cuts, plus it holds vacume from 
> the top...
> 
> Is that normal that it will leak thru the piston? or my piston is worn-out?
> (i think is a piston that goes up & dowm..I have not take it apart yet)
> 
> 
> You're going at this the wrong way...  The wastegate doesn't open and close only 
> due to pressure on the diaphragm.  In fact, if you were to pressurize the 
> diaphragm enough to open the wastegate, I believe you would rip it.  The 
> diaphragm and ports exist only to "modify" the effect of the wastegate spring... 
> to make minor adjustments to opening and closing by "strengthening" or 
> "weakening" the overall effect of the spring.
> 
> The heavy lifting is done by the exhaust pressure applied to the bottom of the 
> WG.  Unless you know the exact relationship between exhaust pressure and boost 
> (and you don't, nor do I), you will not be successful in setting up the WG on 
> the bench to provide 14lbs of boost.  You need to do this by running the car and 
> adjusting the preload on your WG spring.
> 
> hth,
> 
> Dave
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