UrS6 - oem Wastegate Queries

[macspring]

Has anyone ever refurbished their waste gate and noticed any improvement ? Was there anything noticeable wrong with it when you took it apart ?

Also has anyone just replaced the diaphragm / membrane and noted any change / improvement ?

Just curious as my UrS6 sometimes boosts on the dash readout to 2.2, 2.3, and then sometimes 2.4, and can't really deduce why it is not 2.4 all the time ?

My understandings that these oem wastage's are good and can be used even for high power engines, but was wondering if there is a good aftermarket one that bolts on / is plug 'n play ?

It is fried.

Car has less than 50k miles and is very fresh.

N75 valve is new as is the bypass valve, NGK plugs, and 1.8T style coils.

Any advices appreciated.

Thanks.

[diesel des]

The stock unit is very good in my opinion. It's likely something else is causing your strange boosting. But put a proper boost gauge into confirm.

[hunker7]

Car has less than 50k miles and is very fresh.
.

Off topic, but do you have any pictures of your UrS6?

[UrS4boy]

Just curious as my UrS6 sometimes boosts on the dash readout to 2.2, 2.3, and then sometimes 2.4, and can't really deduce why it is not 2.4 all the time ?

That is occurring because that is what the computer is telling the N75 to create. With a properly operating AAN (or ABY or ADU) boost system (ECU with good MAP sensor and software, plus working and connected N75), the ECU is making decisions about the N75 duty cycle based on its internal "3D" boost map (look-up table). Sometimes 2.2 Bar (Absolute pressure by the way) suits, sometimes 2.4 (over boost BTW) suits. There is nothing wrong with either your wastegate or the N75 by the sounds of it. Just your expectations.

Sorry.

[krzysztofkabaj]

I did full rebuild of my WG. New diaphragm, new valve guide, full machining. Was worth it

[UrS4boy]

I did full rebuild of my WG. New diaphragm, new valve guide, full machining. Was worth it

What problems were solved by doing that?

[krzysztofkabaj]

General physical condition regarding todays new WG avaliable on market, more over diaphragm torn apart and after that found out valve guide in bad condition. Choice was : buy new aftermarket one or rebuild old. I like shape/look of it so i took it and rebuilded.

[bertman]

I rebuilt mine from ones I have collected over the years.My original one had a lot of scoring on the valve shaft and some of the threads to hold the cap down were becoming loose and turning on themselves.
Got hold of a very low mileage waste gate and took it apart and found the valve stem to be in excellent shape.Put back together with the new diaphragm off my original and it seemed to pull harder but that could have been my imagination.
Waste gates that have a lot of miles on them in some instances can get a bit sticky where there is excessive wear on the valve shaft but other than that they are very robust and reliable

[twoqu]

Agreed!
The problems start with the erosion of the coating on the valve stem (asssuming it is hard chromed). My theory is that this is due to it effectively being in a fixed position relative to the exhaust gas.
I for one would be interested to hear how this issue can be fixed. I was looking at either trying to get existing valves recoated oversize and machining the existing guide back to tolerance but I could not find any empirical data on the necessary clearances.

[hunker7]

I did full rebuild of my WG. New diaphragm, new valve guide, full machining. Was worth it

Have more information on parts and how it is done?

[krzysztofkabaj]

After dismantling the valve turned out to be :





Guide and valve shaft as You can see Was in bad shape, diaphragm ripped in pieces. Pics did after dismantling valve on parts.
To extract valve guide there's need to heat it real good and use press or gently (I mean it) use medium hammer and puncher and slowly hit guide out of the WG body.
Next i measure guide and made new one, inner finishing polished. Valve shaft during long term "workout" was machined for diameter 9.18mm, valve guide (my memory starts to fail :-P ) to 9.2mm giving clearance of 0.02mm. I.E. exhaust valves tolerance is +/- 0.05mm.

I must disappoint beacause no standard parts were used during my rebuild operation . After that valve does not stick, it is seal, no overboost spikes, no surprises, so on so on ....

P.S. excuse my bad english .