AAN Wastegate Spring and Setup?

[Andyh-R6S]

The used standard wastegate assembly arrived today and has obviously never been tampered with, unlike the one fitted to my car!

Where would I get a ‘new’ standard spring from in England? Alternatively, running a MTM phase one conversion, should I go for a different spring (i.e. 1.9bar) or is it better keep it standard and let the ECU do its business?
(What is the ‘standard’ spring pressure opposed to the modified versions?)

Since the top cover of the wastegate has not been messed around with (Still has the little cover over the adjustment screw) and I cannot say it came of an ‘AAN’ engine car, is there a setup procedure when starting from scratch? (I only intend to change the top cover. The diaphragm in my wastegate is in perfect condition)

Lastly, I had all the 034 Motorsport ignition kit off the car at the weekend and all looks OK. (No burning to any of the connectors or coils, etc.)

[Animal Mother]

Sorry if I've missed something but why don't you just replace the whole unit or use the spring in the new unit. As long as it has the anti tamper seal intact it should be ok.

[Jamo]

The used standard wastegate assembly arrived today and has obviously never been tampered with, unlike the one fitted to my car!

Where would I get a ‘new’ standard spring from in England? Alternatively, running a MTM phase one conversion, should I go for a different spring (i.e. 1.9bar) or is it better keep it standard and let the ECU do its business?
(What is the ‘standard’ spring pressure opposed to the modified versions?)

Since the top cover of the wastegate has not been messed around with (Still has the little cover over the adjustment screw) and I cannot say it came of an ‘AAN’ engine car, is there a setup procedure when starting from scratch? (I only intend to change the top cover. The diaphragm in my wastegate is in perfect condition)

Lastly, I had all the 034 Motorsport ignition kit off the car at the weekend and all looks OK. (No burning to any of the connectors or coils, etc.)

http://www.sjmautotechnik.com/parts_products/wginst.html

I'm not 100% but I think you need to have the map changed to accomodate the new wastegate spring.

It will allow the car to boost quicker but it reduces ECU failsafe as the car will boost to 0.9 bar minimum instead of 0.4 bar when a fault condition occurs.

[Andyh-R6S]

The only decent bit of the used wastegate was the top cover, which has cleaned up quite well.

It would appear that it’s never been apart except for today, just a little concerned that the spring might not be correct for my car as I do not know what engine it’s come from! Would rather stick a new spring in for the sake of a few quid.

But for the time being, I will use my original spring with the new (used) wastegate top cover and use new stainless steel cap bolts and washers.

The “sjmautotechnick” web page suggests, that oxygen sensors over “60k miles” should be replaced! Has anybody done this and noticed a difference? As mine is around "110K miles".

I will see what happens at the weekend when I next use the car.

[S2central.net]

Yes - change the lambda probe every 60k miles - its a very imprtant sensor. Its accuracy decreases with age. Buy an original VAG or Bosch item - don't be tempted to scrimp on a cheapo pattern part - false economy every time.

[Andyh-R6S]

Great, I will get a new Lambda probe one ordered from VAG parts. (Would you notice anything as it degrades, etc?)

The write up also suggested that it would be a good idea to change the ‘WOT’ switch as well and clean out the idle stabilisation valve, etc.

Are ‘WOT switched expensive?

[Jamo]

I would just get the car VAG-COM checked to see if WOT is actually been seen by the ecu and if not adjust the throttle cable.

ISV valve easy clean with carb cleaner and WD40

[UrS4boy]

I'm not 100% but I think you need to have the map changed to accomodate the new wastegate spring. It will allow the car to boost quicker but it reduces ECU failsafe as the car will boost to 0.9 bar minimum instead of 0.4 bar when a fault condition occurs.

This has NOT been my experience. My 93 S4 AAN is RS2'd with generic MRC RS2 software (for RS2 injectors and MAF). I was running the OE waste gate spring with the "anti-tamper" cover removed and six turns down from stock. Didn't like it that much. Tried the 034 1.9 Bar WG spring with the same setting. The "snap" was great but the rate of boost rise was too much for the ECU and it would buck and jerk. Solution was to turn the WG adjustment hex screw all the way out (no threads showing).

Now its perfect. Lots of initial snap (boost rise) but not too much so as to bother the ECU (it copes just fine). I did think about screwing the adjustment screw in a bit but decided to leave well enough alone.

If you have not removed a WG cap or the "anti-tamper" seal/adjustment screw cover, you might want to read this:

http://forums.audiworld.com/s4s6/msgs/149838.phtml

Dave F.

[AndyP]

Is the 1.9bar spring supposed to raise mechanical boost to 1.9bar or is it 0.9bar? I tried one in my S4 the other day ( mapped for 1.4bar boost ) and the boost was still climbing at 1.7bar when I backed off. I'd always assumed that the spring just raised mechanical boost from 0.4bar from 0.9bar?

[UrS4boy]

Is the 1.9bar spring supposed to raise mechanical boost to 1.9bar or is it 0.9bar? I tried one in my S4 the other day ( mapped for 1.4bar boost ) and the boost was still climbing at 1.7bar when I backed off. I'd always assumed that the spring just raised mechanical boost from 0.4bar from 0.9bar?

To be honest, I never thought about it. However, doing the math (conversion to psi, that I am more confortable with), yes it makes sense: 0.4 Bar =~ 6 psi (which is what we, in North America, assume/know for the WG only mechanical boost) whereas 0.9 bar =~ 13 psi. However, I would only see that IF I disconnected the intake to ECU boost pressure hose OR the WGFV.

All I can say is the maximum boost is still the same, about 27 psi =~ 1.86 Bar, as it was with the stock spring. (MRC chipset)

This is with the 1.9 bar spring perch turned all the way up.

[Andyh-R6S]

Slight Hesitation under acceleration again!!!!!!!

After being back in the country again after months away, I forgot about the slight hesitation my car had although not as bad as the original hesitation, need help again please.

Now before everybody says ignition coils and/or air leaks, its none of those as it’s been fully tested numerous times by myself and the garage I use and I know that those bits of kit are good. It might be a good idea to read all of the data below before commenting, as I have done everything that has been suggested to me, etc.

Basically, ever since it had its MTM ecu upgrade the cat has had a slight hesitation under full throttle acceleration. (It did have the Frankenstein bolt in the wastegate top cover)

Now then:
After replacing all the ignition coils for the 034 M’Sport set up, it still did it.

Changed the plugs, torqued down correctly, still does it.

Checked and replaced lots of vacuum hoses and boost hoses with Samco kit, even if they did not need it, no difference. (Vacuum tested OK before and afterwards, removing a vacuum hoses made a big difference as expected)

Changed the Lambda probe, no real difference. (Although generally smoother acceleration all round. Old probe 110k miles)

Replaced the MAF for new one and put a new air filter in, still did it.

Replacing the ‘Frankenstein’ wastegate top cover with the extra ’13 to 14mm’ of spring compression compared to the standard one (Virgin and tamper proof cover still in place) I fitted, removed the full throttle (3200 to 3700rpm) hesitation but then I got back for free, a general part throttle hesitation, flooring the throttle though gives no hesitation at all, interesting. (An it really does go)

Could it be that the standard wastegate needs to be screwed down (one complete turn at a time and go for a blast) or do I need a stiffer spring, as I am wondering if I just need to set the spring up to get the correct balance, in as much that the wastegate is now opening to early compared to previously it was not opening at all due to the excessive wastegate spring pressure with the Frankenstein top cover, so the WGF was being toggled by the ECU to reduce the boost.

Or is it possible that when the ECU conversion was done, the 3 bar map sensor it should have got according to the sales blurb, was not done or could it be faulty?

No fault codes except what I generated changing parts, wipe the memory clean and nothing is logged when it’s doing the phenomenon.
I admit I have not used the car for nearly ‘5’ months due to my job but as soon as I got it on the motorway to take it for its MOT, service and general inspection it started doing it again.

This is really doing my head in.

Anything it could be that does not generate a fault code?

Or I am looking at canning the ‘MTM ECU conversion’ and saving up for a ‘MRC’ remap? (I hope not, as money cannot be wasted at present.)

[Rusty]

Under anything else. Had a funny like this with a mate's avant where it hesitated at 3k rpm when you accelerated. Turned out to be an air leak on the low pressure side where the inlet hose had split.

[Andyh-R6S]

Do you mean the big hose from the MAF to the Turbo??

Apart from looking at it generally in the past, it looked OK but I will look at again when I get back from the garage, as I think they are none the wiser anyway.

Ta,

Andy H.

[macspring]

Andy,

You may have posted elsewhere, but reading this thread now I'm keen to know what the cause was. I'm assuming you nailed it in the end, rather than continuing to suffer the problem.

I also have an MTM, presumably stage one conversion to say 270 bhp, and was toying with the idea of fitting the 1.9 wastegate spring.

Found this thread after a search.

Not sure if the MTM conversion automatically changes the standard spring up to this 1.9 spring as a matter of course?

http://www.034motorsport.com/product_info.php?products_id=198

BTW, with a new lambda probe in mine, it did slightly better miles to the gallon, and it stands to reason that it is a consumable, so was happy to change it, to rule out any possible problems it could or might be causing, can't get better than new type of idea?

One small aside, a pinking on full throttle was cured by changing the fuel filter, it appeared to be the original after 130 odd thousand miles.

Lastly, recently changed a small one and a half inch length vacuum hose at the back of the inlet manifold that T's off into two and one goes to the ECU, the car seems to spool up slightly earlier. Not sure, but I think so, haven't driven it much over the holiday period. The old one looked was intact, but a bit ropey. It was not air tight when tested off the car. Still only boosts to a max. of 1.5 bar.

Thanks and kind regards.