waistgate chatter
31 May 2007, 07:36 PM
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it's not the wastegate chattering.. it is the turbo stalling as the air passes back through it..
run without a dumpvalve and you get it.. but not on a VF turbo as you will find the blades snap off.
Simon
run without a dumpvalve and you get it.. but not on a VF turbo as you will find the blades snap off.
Simon
31 May 2007, 07:52 PM
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31 May 2007, 08:17 PM
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NASIOC - View Single Post - '06 WRX acceleration rattle
post describing wastegate chatter/flutter.
jolly green monster- if this isn't waste gate chatter could you please add comment/insight for background info? Thanks.
post describing wastegate chatter/flutter.
jolly green monster- if this isn't waste gate chatter could you please add comment/insight for background info? Thanks.
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31 May 2007, 08:45 PM
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NASIOC - View Single Post - '06 WRX acceleration rattle
post describing wastegate chatter/flutter.
jolly green monster- if this isn't waste gate chatter could you please add comment/insight for background info? Thanks.
post describing wastegate chatter/flutter.
jolly green monster- if this isn't waste gate chatter could you please add comment/insight for background info? Thanks.
Wastegate chatter myth
There is a common myth in the automotive world about so called "wastegate chatter", a noise created on lifting off the throttle in a turbocharged car. The sound is commonly described as a chipmunk or a rattlesnake and is often stated incorrectly as being a result of the turbo's wastegate closing.
The noise is in fact the air compressed by the turbo passing back through the compressor housing of the turbo after having hit the now closed throttle plate. This is also known as Compressor Surge and over time can result in significant damage to the turbocharger. It damages the turbocharger by bringing the compressor blades (which spin in excess of 100,000 RPM) to a near dead stop almost instantaneously. This puts an enormous amount of stress on the blades which causes them to fatigue faster. To avoid this turbocharged cars will use a blowoff valve (BOV), which allows the extra pressurized air in the intake out. However, in some cases, i.e. where it doesn't open fast enough or is setup to only react to high boost, some chatter will remain.
The chatter noise is very noticeable on WRC Rally cars, where no BOV is allowed.
"This has also been known as "Turbo Flutter" and in some cases, adding a BOV can increase the flutter especially if you have an intake system. Once the air hits the closed plate, the only path it has to exit is through the intake."
There is a common myth in the automotive world about so called "wastegate chatter", a noise created on lifting off the throttle in a turbocharged car. The sound is commonly described as a chipmunk or a rattlesnake and is often stated incorrectly as being a result of the turbo's wastegate closing.
The noise is in fact the air compressed by the turbo passing back through the compressor housing of the turbo after having hit the now closed throttle plate. This is also known as Compressor Surge and over time can result in significant damage to the turbocharger. It damages the turbocharger by bringing the compressor blades (which spin in excess of 100,000 RPM) to a near dead stop almost instantaneously. This puts an enormous amount of stress on the blades which causes them to fatigue faster. To avoid this turbocharged cars will use a blowoff valve (BOV), which allows the extra pressurized air in the intake out. However, in some cases, i.e. where it doesn't open fast enough or is setup to only react to high boost, some chatter will remain.
The chatter noise is very noticeable on WRC Rally cars, where no BOV is allowed.
"This has also been known as "Turbo Flutter" and in some cases, adding a BOV can increase the flutter especially if you have an intake system. Once the air hits the closed plate, the only path it has to exit is through the intake."
31 May 2007, 09:05 PM
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depends on the turbo.. if you have the standard TD05 fitted then no bother..
done about 100k miles without a dumpvalve on one.. it is really only the VF turbos on the Scoobs that won't last long without a DV.
Simon
done about 100k miles without a dumpvalve on one.. it is really only the VF turbos on the Scoobs that won't last long without a DV.
Simon
31 May 2007, 09:09 PM
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Note if you have a crap or badly adjust aftermarket DV and a cone filter (or no resonator), you can get chatter noise...another reason to stick with the factory DV 
31 May 2007, 09:50 PM
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what turbo will i have on my 03 wrx 
Love the sound but would hate the expense of a repair , also when you say remove the dv do you need any bungs for the exposed pipes etc ,
A quick discription of what to do would be superb ,
Dave
Love the sound but would hate the expense of a repair , also when you say remove the dv do you need any bungs for the exposed pipes etc ,
A quick discription of what to do would be superb ,
Dave
31 May 2007, 10:51 PM
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jolly green monster - looks like we're on about different things here. The above post is about the wastegate chattering before full boost pressure is achieved, which i think is possible havin read the above, not when lifting off the throttle as you've mentioned above? not an expert or claiming to be one just trying to build up a bit of background knowledge
31 May 2007, 10:56 PM
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31 May 2007, 11:11 PM
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jolly green monster - looks like we're on about different things here. The above post is about the wastegate chattering before full boost pressure is achieved, which i think is possible havin read the above, not when lifting off the throttle as you've mentioned above? not an expert or claiming to be one just trying to build up a bit of background knowledge
01 June 2007, 08:56 AM
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do i? lol! I have a slight flutter/chatter at 2-2.5k just before boost builds which having read some things on other forums, is the wastegate chattering before full boost is achieved or as you suggest compressor surge across it causing the wastegate to chatter slightly. I'm looking to stop this or at least lessen it as its quite annoying on a nearly new car when i've been in loads of others that haven't done it. Dealer changed boost controller to no avail but i now think it could be that the wastegate needs adjusted slightly as its lifting early? Whats your opinion on this? thanks.
01 June 2007, 11:27 AM
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Please, no more, no more...if I find out who popularised the term 'wastegate chatter'...
If only more people knew what a wastegate even looked like or how it functioned they'd know it was ridiculous to expect to hear it making any bloody noise at all.
What you have sounds like compressor surge.
If only more people knew what a wastegate even looked like or how it functioned they'd know it was ridiculous to expect to hear it making any bloody noise at all.
What you have sounds like compressor surge.
01 June 2007, 01:52 PM
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Please, no more, no more...if I find out who popularised the term 'wastegate chatter'...
If only more people knew what a wastegate even looked like or how it functioned they'd know it was ridiculous to expect to hear it making any bloody noise at all.
What you have sounds like compressor surge.
If only more people knew what a wastegate even looked like or how it functioned they'd know it was ridiculous to expect to hear it making any bloody noise at all.
What you have sounds like compressor surge.
01 June 2007, 01:53 PM
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do i? lol! I have a slight flutter/chatter at 2-2.5k just before boost builds which having read some things on other forums, is the wastegate chattering before full boost is achieved or as you suggest compressor surge across it causing the wastegate to chatter slightly. I'm looking to stop this or at least lessen it as its quite annoying on a nearly new car when i've been in loads of others that haven't done it. Dealer changed boost controller to no avail but i now think it could be that the wastegate needs adjusted slightly as its lifting early? Whats your opinion on this? thanks.
01 June 2007, 05:30 PM
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Please, no more, no more...if I find out who popularised the term 'wastegate chatter'...
If only more people knew what a wastegate even looked like or how it functioned they'd know it was ridiculous to expect to hear it making any bloody noise at all.
What you have sounds like compressor surge.
If only more people knew what a wastegate even looked like or how it functioned they'd know it was ridiculous to expect to hear it making any bloody noise at all.
What you have sounds like compressor surge.
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