What is the factory Wastegate Spring Pressure?

[Andyh-R6S]

I have to ask these questions for an UrS6:

1. What is the standard wastegate spring pressure and does this take into consideration the factory setup? (i.e. 1.1, 1.3, 1.5, etc)

2. If you went and bought a “1.9 bar” spring and fitted it into a factory set wastegate top cover, would actually have a higher spring pressure than the ‘1.9 bar’? (i.e. is the factory setting in the wastegate top cover worth say ‘0.2 bar’ so you would actually have ‘2.1 bar’ effective?)

I cannot find any reference to the factory spring pressure anywhere and it will help me understand the full picture for comparative testing I might do. ((i.e. taking out a ‘1.5 bar’ spring and fitting a ‘1.9bar’ spring, etc.) Before and after, etc)

Regards,

Andy H.

[S2central.net]

Dunno what the factory rating on the correct spring is, but with it fitted and the WGFV disconnected you should get no more than 0.4bar boost... There is approx 25mm spacing between the upper perch on the WG spring and the inside surface of the WG cap.

Paul

[PeteRR]

...There is approx 25mm spacing between the upper perch on the WG spring and the inside surface of the WG cap.

Paul

Paul, I've been meaning to ask if by the upper perch, do you mean the surface facing the inner surface of the wastegate cap? Or the other side, where the spring seats? (I'm contemplating going from AmD to Homefries myself).

[newsh]

The stock spring is a 1.4Bar of spring (absolute) so allows 0.4Bar of boost above atmospheric pressure. At the standard setting of the Wastegate spring perch. A 1.9Bar spring will allow a boost of 0.9Bar with some adjustment each way by adjusting the screw. My 1.9 spring is set to give 1 bar approx at part throttle with the other Bar coming in courtesy of the ECU and WGFV at WOT.
If you fit a 1.9 Bar spring you must remap the ECU or it will exceed the limits of the MAP sensor and overboost at WOT.

[S2central.net]

Paul, I've been meaning to ask if by the upper perch, do you mean the surface facing the inner surface of the wastegate cap? Or the other side, where the spring seats? (I'm contemplating going from AmD to Homefries myself).

Good point - my memory of this is that its the surface facing the innerds of the WG cap - not actually where the spring seats. There's only about 2-3mm difference there so its not that crucially accurate. If you are unsure, its easy to test with WGFV disconnected and check you see 0.4bar though its OK to wind up a little more if you feel frisky.

Let me know on the homefry front - you wont be the 1st to change from AMD I tell thee. You can try the loaner if you like when I get it back next week.

Paul

[UrS4boy]

If you fit a 1.9 Bar spring you must remap the ECU or it will exceed the limits of the MAP sensor and overboost at WOT.

I am running a 1.9 Bar spring on my RS2'd AAN with MRC software and did not have to remap. However, I did turn the spring perch all the way up because at the standard WG cap setting, I did get some overboost stutter (it seemed that the rate of boost rise was faster than the ECU could figure out what to do with it). I like the end result, nice snap and no issues at WOT. I keep meaning to turn down the spring perch a bit to find out when I get "issues" but I decided to let the sleeping dog lie.

[S2central.net]

The WGFV programming is adaptive to cater for different springs, but there are limits as to how far it can adapt automatically without needing to reprog on a very stiff spring as you found out.

I have also meant to try dabbling with different WG setting on the old homefries just to get an idea of where the limit is, but its another happily sleeping dog

PAul

[Andyh-R6S]

1.9 bar WGT spring then, may be???

OK then:

If we say an UrS4/S6 under 'factory conditions' is running a ‘1.5 bar WGT spring’ and tops out under normal conditions somewhere between ‘1.7 to 1.8 bar’ boost with standard Audi software.

If the modified software you are running gives ‘2.2 to 2.3 bar’ boost, would it be fair to say, using the factory set WGT top cover, that a 1.9 bar WGT spring would not really need any changes to the WGT spring pre load? Since changing the WGT top cover for a standard version, (Although my previous issue has been rectified) the performance is now lack lustre, although WOT is ballistic when the rubber band is lets loose. I do not really want to mess about with the WGT cover adjustment after going to the trouble of getting a standard one. Although I do not mind playing around a bit, especially if changing the WGT spring for a ‘1.9 bar’ from the ‘1.5’ stock item gives the sparkle back under normal (not WOT) driving conditions.

New Lambda arrives tomorrow, however I cleaned the old one out the best I could using ‘carb cleaner’ (You should have seen the muck that came out of the three bowed slits!!) and over the last two days the MPG has increased by around ‘3 to 3.5 mpg’. (200 miles) Now getting on a sensible run with no progressive driving around ’27 to 28’ rather than ‘23 to 24’. Super job. It will be interesting to see if I get even better MPG with a new Lambda probe!!!

Bought some Samco ‘8mm’ hose to sought the other area out. Thanks for the info and web links, etc.

[UrS4boy]

Personally, with a stock WG spring, I would not be worried about removing the adjustment cap from your "virgin" WG cap. You gotta lose it sometime.

Once it is off, then you can experiment a bit. Conventional wisdom on the AAN forums was a maximum of 6 turns down from the OE setting with an OE spring. Like I said, with the 1.9 bar spring, even stock setting was too much and I had to back it all the way up. But the results are worth it (personal opinion)

[Andyh-R6S]

Where in the UK can a ‘1.9 bar’ spring be purchased, new? And at what cost?

[k.alle]

Where in the UK can a ‘1.9 bar’ spring be purchased, new? And at what cost?

Here's a 0.8 bar spring (or 1.8bar if you like), It's in Germany though but they ship to Europe.
http://cgi.ebay.de/Wastegate-Audi-5-...QQcmdZViewItem


27,50€ + shipping, not to bad.

[UrS4boy]

Where in the UK can a ‘1.9 bar’ spring be purchased, new? And at what cost?

I got mine from 034 in the States. US$45 plus shipping. Presumably you could get one through quattronics (Corey).

http://www.034motorsport.com/product_info.php?cPath=21_99&products_id=198

[alg]

Can you get a standard RS2 spec spring from anywhere ? OEM is only via a new wastegate !

[newsh]

Can you get a standard RS2 spec spring from anywhere ? OEM is only via a new wastegate !

Try MRC, they should have a pile of them they've taken out of stock WGs, I had a few but I think they're all gone now.

[alg]

Really looking for a new one......