hi all , can anyone explain wot an external wastegate is ? and what it actually does please .cheers

 

http://en.wikipedia.org/wiki/Wastegate

 

Thanks mate , interesting and also explained the other thing i was wondering about ? screamer pipes and the so called " waste gate chatter " u learn sumthin new every day

 

wastgegates open when the turbo sees too much boost.

 

Looking at the wiki article about "wastegate chatter" it says this:

"Actual wastegate flutter occurs instead under partial boost conditions such as partial throttle near the boost threshold. It sounds like FftFftFft not ShuShuShu and is caused by the rapid opening and closing of the wastegate at boost levels near the spring pressure."

Is this correct? Doesn't sound right to me at all. A wastegate is not an on, off device like a solenoid. As you reach the set pressure the force overcomes the spring in the actuator and starts to open the wastgate diverting some of the exhaust gasses around the turbo, as the pressure overcomes the spring it compresses it. The more pressure the more it compresses and the more the wastegate opens. When you reach a certain point the wastegate is fully open and if it can not flow any more you will get boost creep. At least that's my understanding of it. So is that part of the article a load of crap?

 

what does it sound like again lol?

 

The chatter sound comes from the air going back and hitting the turbo blades, only happens if you dont run a dumpvalve and loving the description of the sound

 

Can we open up the old compressor stall vs wastegate chatter debate so I can do a bit of mythbusting? lol!

Graham

 

Knock yourself out

 

Anyone care to donate a chattering car for an hour or so? I might be able to find one to play with. Definately got to mythbust that hearsay for sure!!

Graham

 

Remember the "chuffing sound" the velocoraptors in Jurassic park made? That's how I describe the sound of running without a DV!

 

my car chatters at lowish boost/rpms and only dumps when the revs are higher and the boost is more, best of both worlds!

 

I know that wastegate chatter is a load of crap and the noise is from compressor surge, I was just wondering if the statement made on wikipedia was correct, as it sounds like bull sh*t to me? They explain about compressor surge, but then go on to say that "real" wastegate chatter is something else. I don't think it exists at all.

 

well i turbocharged a 1.4 single point injection astra once, and when you revved it to make it chatter if you watched/held the actuator rod it oscilated back and forth in time with the chatter noise. Never seen this before or since, but i thought i may be worth a mention