jlee

I took my car to the dealer to have them replace or check out the diverter valves but they would not do it unless they can reproduce the noise. The problem is that it only happened two times during about 2000 miles of driving. I am just concerned that I may be losing power without even knowing it. I have read in earlier posts that people could be driving around with defective diverter valves and not even know that they are losing horsepower. My car is a tiptronic and, using an accelerometer I measured 0-60 time of about 4.7 sec on a slightly curving road going uphill(mild to moderate grade). The road was wet but the traction control did not come on. Does this sound like I am loosing power?

MBailey

I cant say if your loosing power or not. I do know that accelerometer measurments are not accurate on any kind of an incline. Your acceleration will also suffer if you have to turn the wheels to negotiate a curve. There are too many other variables present such as temp, barometric pressure, altitude, humidity ect... to say for sure.
It is my understanding is that when the diverters fail you will know it by the honking or whining noise consistantly under boost or right after you let off boost. You can always buy the DVs and replace them yourself.

jlee

Thanks Bailey. I am going to probably change the DV to aftermarket ones as a precaution.

Blue S2

Arent the stock diverter valves the same ones the Audi TT & GTI use? I believe they are. I changed my diverter valve (GTI with 1.8T) to an aftermarket Forge valve. Evolution Motorsports (www.evoms.com) makes them for the 996, and it seems to be the same design for both our engines. (996 valve sits differently than mine) Stock is a diaphram design that rips. Once it is really broken, you will definitely hear a stuttering blow-off, or honking type sound. You can still drive, but you lack the pressure. If you go with an aftermarket piston style DV you shouldn't ever have a problem. A little trick i was shown when i bought mine direct- reverse the two large "arms." So if the long arm is going to one hose, switch it to the other hose. Make sure the small, top hose remains the same. Now when you blow off not only do you get a whoosh, but you also get a metallic "shink" sound, similar to cheesy sword effects in a Highlander movie. No ill effects, ive tested both ways. The piston works the same way. With a modified intake it sounds great. I wonder what it would sound like with two valves!