Can it be that a boostspring(wastegate) becomes weak?
 

Can it be that a boostspring(wastegate) becomes weak?

The valve can become covered with coke and not seat properly and the spring will fatigue with age. So yes the wastegate can become less crisp in response or accurate with age. Complete failures can occur in cars that sit for extended time as oxidation forms and hoses become brittle.

Add to that valve guide wear and too much boost air bypassing via a bad guide, and you'll have a sluggish WG. Or coke buildup in the guide itself, causing the valve to hang-up and not fully seat. As Brian mentioned, I suppose that the spring can eventually loose it's "spring" due to constant heat affecting the spring temper over time.
These WG's are pretty bullet proof, but they do eventually start to show symptoms in high mileage cars. Fortunately there are great aftermarket solutions.

The owner's manual actually suggests the operator open the waste gate via full throttle runs every time the car is used in order to preserve the waste gate function. Doubt if strict adherance to the owner's manual would be a good defence in court though, ha!

Thanks for your information. damn what a knowledge you have :eek:
your very helpful to me and all other porsche owners!
RESPECT
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The first time I read that in my owners manual I figured it was a license to mis-behave. Supposed to blast out any accumulated condensation, prevent corrosion I guess.

I always crank my car up to full boost in 1st gear as soon as I leave the driveway. Got maybe 100 yards before the first stopsign...no problem! Neighbors, kids, dogs, cats, cops be damned....here I come:D

Mis-behave ... mm there is something strange but it's not hole the time
but when i accelerate a bit and it release my peddle instead of slowing down he first accelerate a second and then slow down normally. do you understand what I'm trying to explain? it's difficult for me to find the exact words... i do my best:D

When wide open throttle, pedal to the metal and on boost, the warmup regulator will enrichen the mixture quite a bit. So, if you let off partially on the throttle the boost pressure will be diverted and the engine will lean out momentarily...which may cause a brief acceleration as you discribe. I don't notice that in my car, but then I've got it pretty well tuned in with an adjustable WUR. Your car might be too rich either on or before boost, I suppose. Or perhaps just the opposite is happening with too lean on boost and getting richer when you let off.

That's my guess, anyway. Anybody else got any input?