Turbo flutter/chatter
07 July 2009, 11:30 PM
#1
Scooby Regular
Thread Starter
Join Date: Apr 2009
Posts: 38
Likes: 0
Received 0 Likes
on
0 Posts
Turbo flutter/chatter
Guys,
Forgive me, being a newbie i'm absolutely confused!
I've read 100's of posts up here on SN and I cant seem to get a solid answer!
Basically, the turbo flutter/chatter sund is something my heart has taken a likening too and all i want to know is on my MY99 UK T2000 (TD04 turbo PPP panel filter tmic 3" ZS decat exhaust) would it be possible to get this sound?
I have the standard recirc DV on but I just need a solid answer perhaps from someone well experienced or who has tried it themselves that is it possible to get this sound with this set up without causing any damage?
I'm sure theres quite a few newbies that would really like to know!
Thanks guys!
Forgive me, being a newbie i'm absolutely confused!
I've read 100's of posts up here on SN and I cant seem to get a solid answer!
Basically, the turbo flutter/chatter sund is something my heart has taken a likening too and all i want to know is on my MY99 UK T2000 (TD04 turbo PPP panel filter tmic 3" ZS decat exhaust) would it be possible to get this sound?
I have the standard recirc DV on but I just need a solid answer perhaps from someone well experienced or who has tried it themselves that is it possible to get this sound with this set up without causing any damage?
I'm sure theres quite a few newbies that would really like to know!
Thanks guys!
08 July 2009, 06:27 AM
#3
Scooby Regular
Join Date: Jan 2006
Posts: 3,695
Likes: 0
Received 0 Likes
on
0 Posts
and all i want to know is on my MY99 UK T2000 (TD04 turbo PPP panel filter tmic 3" ZS decat exhaust) would it be possible to get this sound?
I have the standard recirc DV on but I just need a solid answer perhaps from someone well experienced or who has tried it themselves that is it possible to get this sound with this set up without causing any damage?
Creating the conditions to generate that noise isn't that difficult. You remove the dumpvalve completely and block off the resultant holes. Then, when you lift off the throttle under boost, instead of the excess air being dumped out the valve, it has nowhere to go and is forced back into the turbocharger compressor and past the blades. This is where the "chatter" noise comes from.
Some will tell you that you can get close by fitting an aftermarket dumpvalve with a very stiff spring. They have a point. However, the point is that you have to use a spring stiff enough to stop the DV from dumping - so the net effect is the same as removing it.
The upside is that, aside from the noise, you will get fractionally better throttle response. The downside is that the noise will be nowhere near as pronounced as it is on the rally cars. They run bigger turbos and about four times more boost (and the more air, the louder the chirping) while the standard induction tract you have quietens things down a lot. As has been said, fitting an induction kit will make it louder, but fitting an induction kit is likely to damage your MAF, (see below), sooner or later.
The big downside, though, is reliability. Removing the dumpvalve will stress your turbo out due to the increased shock loading on the compressor and bearings. The TD04 will cope better with this than some, and they're cheap to replace, but the bigger concern is the risk of damage to the mass airflow sensor.
The reverse air pressure waves travelling through the turbo, up the induction tract and into legendarily fragile MY99-00 MAF will subject it transient shock loading which, after "a period of time", begin to b*gg*r it up.
This causes underreading, underreading leads to underfuelling, and underfuelling leads to overheating and knock, and, if left to fester, an engine that will soon demonstrate its discomfort in a depressing and expensive manner.
You can get around all that by shelling out on a MAP-based ECU, but by that time you have to ask yourself why you spent all that money trying to get your car to make an odd noise. As I've said more than once in the past, if that's what you want, the best way for your car is a sound effects CD and link between the stereo and throttle pedal.
Some run with it without any problems, but doing it on an MY99-00 is inherently riskier than any other model year due to the inherent fragility of the airflow sensor.
08 July 2009, 04:14 PM
#5
Scooby Regular
Thread Starter
Join Date: Apr 2009
Posts: 38
Likes: 0
Received 0 Likes
on
0 Posts
Guys,
Thanks for all your help!
Splitpin - amazing answer, thank you for your help and committment on this issue. It seems best to stay away from this considering the car's 10 years old anyway!
:luxhello :
I found out all i needed to know from your answer, very helpful mate!
Thanks
PS How do I know if my MAF sensors gone?
Thanks for all your help!
Splitpin - amazing answer, thank you for your help and committment on this issue. It seems best to stay away from this considering the car's 10 years old anyway!
:luxhello :I found out all i needed to know from your answer, very helpful mate!
Thanks
PS How do I know if my MAF sensors gone?
08 July 2009, 04:44 PM
#6
Scooby Regular
Join Date: Jan 2006
Posts: 3,695
Likes: 0
Received 0 Likes
on
0 Posts
PS How do I know if my MAF sensors gone?
Any of those will give you advance warning of the underfuelling that hallmarks a degrading MAF before it becomes critical. Monitoring knock is a good idea in general because it can pick up other issues on the engine that can, if left, get nasty.
Trending Topics
08 July 2009, 04:53 PM
#8
Scooby Regular
Join Date: Jan 2006
Posts: 3,695
Likes: 0
Received 0 Likes
on
0 Posts
I'd also ask anyone suggesting this method how a test done at idle can validate (or otherwise) a sensor's accuracy under high engine speed and boost?
Last edited by Splitpin; 08 July 2009 at 05:31 PM.
08 July 2009, 05:46 PM
#10
Scooby Regular
iTrader: (33)
Join Date: Jul 2007
Location: E Yorks
Posts: 4,791
Likes: 0
Received 0 Likes
on
0 Posts
[QUOTE=Splitpin;8810236]Rubbish. Anyone else reading this thread, please feel free to ignore the above (and stop repeating it). If you'd like an explanation of why it's rubbish, please feel free to ask[QUOTE]
crack on then cocker because it worked fine when i did it
crack on then cocker because it worked fine when i did it
08 July 2009, 06:41 PM
#13
Scooby Regular
Join Date: Jan 2006
Posts: 3,695
Likes: 0
Received 0 Likes
on
0 Posts
Tell us all what you mean by "worked fine"? You mean the engine stalled, or the engine didn't stall? How do you know what this proved?
Okay, let's try and put this to bed once and for all. Hope you're sitting comfortably.
Firstly let's look at logic behind your "test". The idea is that you unplug the airflow sensor with the engine running. Then, supposedly, if the engine stalls the sensor should be considered "good". If the engine doesn't stall the sensor should be considered "broken", yes?
So, the internal logic behind this is that, if we assume a "good" sensor, unplugging it with the engine running will remove the airflow voltage from the ECU's sensor input, the ECU will immediately know something is up and cut the engine.
Conversely, if the sensor has "gone bad", there is an inherent assumption that it is sending little or no voltage into the ECU. Therefore when you unplug, the ECU simply doesn't notice and carries on regardless, yes?
The first problem with this test is that, because you're doing it at idle, it has no relevance at all to the performance of the sensor when you really need it to be accurate - during the times when your engine is not idling. Your test is not able, for example, to detect a sensor that under-reads at high airflow levels but is still within the ballpark at idle - which is the failure mode that can damage an engine before the driver becomes aware of it.
Your test could therefore give false confidence that a failing sensor is good, while it proceeds to allow your engine to run lean under boost. Big problem
I've just tested this in practice by plugging in a sensor I know to be totally (and dangerously) b*gg*r*d and disconnecting it while the engine was idling. The engine immediately stalled. Reset the ECU, plugged the duff sensor back in, tried it again. Engine stalled. Ooops. There's one reason why this test is completely useless - it can, and does, pass knackered sensors as good. Major fail.
The second problem with your test is that the sensor is a heated metal film. It measures airflow by determining the amount the film is cooled for a specific amount of heating. The colder the element becomes, the more air is flowing over it (and the hotter it gets, the less air).
The film is connected to the signal processing circuit by minute, very fragile wires. These wires can be damaged by a number of things, primarily vibration. However, removing the electrical supply to the heater while air is flowing over the element will cause sudden cooling and contraction of very small and fragile parts. So, you can inadvertently create a situation where you can damage a perfectly good sensor. Strike 2.
The next problem with your test is the blind assumption you make that the ECU will stall if you unplug a "good" sensor and will not stall if you unplug a "bad" one. Where did you get that idea? Do you know what the ECU is programmed to do under any specific set of circumstances? Do you know what its ability to learn round degraded sensors is? Have you tried repeating the test, say, 10 times with the same sensor, just to see if the result is consistent and repeatable?
No? Strike 3.
Bottom line: This test cannot, with authority, determine the difference between a sensor that is 100% accurate, 80% accurate or 20% accurate, or indeed one that suffers intermittent drop-outs. These sensors become dangerous to the engine if they are under-reading by little more than 5% under boost, and given that your test can "pass" sensors that are degraded beyond this level, as well as "fail" brand new ones, it simply doesn't work.
[/thread hijack]
Okay, let's try and put this to bed once and for all. Hope you're sitting comfortably.
Firstly let's look at logic behind your "test". The idea is that you unplug the airflow sensor with the engine running. Then, supposedly, if the engine stalls the sensor should be considered "good". If the engine doesn't stall the sensor should be considered "broken", yes?
So, the internal logic behind this is that, if we assume a "good" sensor, unplugging it with the engine running will remove the airflow voltage from the ECU's sensor input, the ECU will immediately know something is up and cut the engine.
Conversely, if the sensor has "gone bad", there is an inherent assumption that it is sending little or no voltage into the ECU. Therefore when you unplug, the ECU simply doesn't notice and carries on regardless, yes?
The first problem with this test is that, because you're doing it at idle, it has no relevance at all to the performance of the sensor when you really need it to be accurate - during the times when your engine is not idling. Your test is not able, for example, to detect a sensor that under-reads at high airflow levels but is still within the ballpark at idle - which is the failure mode that can damage an engine before the driver becomes aware of it.
Your test could therefore give false confidence that a failing sensor is good, while it proceeds to allow your engine to run lean under boost. Big problem
I've just tested this in practice by plugging in a sensor I know to be totally (and dangerously) b*gg*r*d and disconnecting it while the engine was idling. The engine immediately stalled. Reset the ECU, plugged the duff sensor back in, tried it again. Engine stalled. Ooops. There's one reason why this test is completely useless - it can, and does, pass knackered sensors as good. Major fail.
The second problem with your test is that the sensor is a heated metal film. It measures airflow by determining the amount the film is cooled for a specific amount of heating. The colder the element becomes, the more air is flowing over it (and the hotter it gets, the less air).
The film is connected to the signal processing circuit by minute, very fragile wires. These wires can be damaged by a number of things, primarily vibration. However, removing the electrical supply to the heater while air is flowing over the element will cause sudden cooling and contraction of very small and fragile parts. So, you can inadvertently create a situation where you can damage a perfectly good sensor. Strike 2.
The next problem with your test is the blind assumption you make that the ECU will stall if you unplug a "good" sensor and will not stall if you unplug a "bad" one. Where did you get that idea? Do you know what the ECU is programmed to do under any specific set of circumstances? Do you know what its ability to learn round degraded sensors is? Have you tried repeating the test, say, 10 times with the same sensor, just to see if the result is consistent and repeatable?
No? Strike 3.
Bottom line: This test cannot, with authority, determine the difference between a sensor that is 100% accurate, 80% accurate or 20% accurate, or indeed one that suffers intermittent drop-outs. These sensors become dangerous to the engine if they are under-reading by little more than 5% under boost, and given that your test can "pass" sensors that are degraded beyond this level, as well as "fail" brand new ones, it simply doesn't work.
[/thread hijack]
Last edited by Splitpin; 08 July 2009 at 07:02 PM.
08 October 2010, 03:51 PM
#19
Scooby Regular
iTrader: (1)
Join Date: Mar 2009
Location: England
Posts: 195
Likes: 0
Received 0 Likes
on
0 Posts
Tell us all what you mean by "worked fine"? You mean the engine stalled, or the engine didn't stall? How do you know what this proved?
Okay, let's try and put this to bed once and for all. Hope you're sitting comfortably.
Firstly let's look at logic behind your "test". The idea is that you unplug the airflow sensor with the engine running. Then, supposedly, if the engine stalls the sensor should be considered "good". If the engine doesn't stall the sensor should be considered "broken", yes?
So, the internal logic behind this is that, if we assume a "good" sensor, unplugging it with the engine running will remove the airflow voltage from the ECU's sensor input, the ECU will immediately know something is up and cut the engine.
Conversely, if the sensor has "gone bad", there is an inherent assumption that it is sending little or no voltage into the ECU. Therefore when you unplug, the ECU simply doesn't notice and carries on regardless, yes?
The first problem with this test is that, because you're doing it at idle, it has no relevance at all to the performance of the sensor when you really need it to be accurate - during the times when your engine is not idling. Your test is not able, for example, to detect a sensor that under-reads at high airflow levels but is still within the ballpark at idle - which is the failure mode that can damage an engine before the driver becomes aware of it.
Your test could therefore give false confidence that a failing sensor is good, while it proceeds to allow your engine to run lean under boost. Big problem
I've just tested this in practice by plugging in a sensor I know to be totally (and dangerously) b*gg*r*d and disconnecting it while the engine was idling. The engine immediately stalled. Reset the ECU, plugged the duff sensor back in, tried it again. Engine stalled. Ooops. There's one reason why this test is completely useless - it can, and does, pass knackered sensors as good. Major fail.
The second problem with your test is that the sensor is a heated metal film. It measures airflow by determining the amount the film is cooled for a specific amount of heating. The colder the element becomes, the more air is flowing over it (and the hotter it gets, the less air).
The film is connected to the signal processing circuit by minute, very fragile wires. These wires can be damaged by a number of things, primarily vibration. However, removing the electrical supply to the heater while air is flowing over the element will cause sudden cooling and contraction of very small and fragile parts. So, you can inadvertently create a situation where you can damage a perfectly good sensor. Strike 2.
The next problem with your test is the blind assumption you make that the ECU will stall if you unplug a "good" sensor and will not stall if you unplug a "bad" one. Where did you get that idea? Do you know what the ECU is programmed to do under any specific set of circumstances? Do you know what its ability to learn round degraded sensors is? Have you tried repeating the test, say, 10 times with the same sensor, just to see if the result is consistent and repeatable?
No? Strike 3.
Bottom line: This test cannot, with authority, determine the difference between a sensor that is 100% accurate, 80% accurate or 20% accurate, or indeed one that suffers intermittent drop-outs. These sensors become dangerous to the engine if they are under-reading by little more than 5% under boost, and given that your test can "pass" sensors that are degraded beyond this level, as well as "fail" brand new ones, it simply doesn't work.
[/thread hijack]
Okay, let's try and put this to bed once and for all. Hope you're sitting comfortably.
Firstly let's look at logic behind your "test". The idea is that you unplug the airflow sensor with the engine running. Then, supposedly, if the engine stalls the sensor should be considered "good". If the engine doesn't stall the sensor should be considered "broken", yes?
So, the internal logic behind this is that, if we assume a "good" sensor, unplugging it with the engine running will remove the airflow voltage from the ECU's sensor input, the ECU will immediately know something is up and cut the engine.
Conversely, if the sensor has "gone bad", there is an inherent assumption that it is sending little or no voltage into the ECU. Therefore when you unplug, the ECU simply doesn't notice and carries on regardless, yes?
The first problem with this test is that, because you're doing it at idle, it has no relevance at all to the performance of the sensor when you really need it to be accurate - during the times when your engine is not idling. Your test is not able, for example, to detect a sensor that under-reads at high airflow levels but is still within the ballpark at idle - which is the failure mode that can damage an engine before the driver becomes aware of it.
Your test could therefore give false confidence that a failing sensor is good, while it proceeds to allow your engine to run lean under boost. Big problem
I've just tested this in practice by plugging in a sensor I know to be totally (and dangerously) b*gg*r*d and disconnecting it while the engine was idling. The engine immediately stalled. Reset the ECU, plugged the duff sensor back in, tried it again. Engine stalled. Ooops. There's one reason why this test is completely useless - it can, and does, pass knackered sensors as good. Major fail.
The second problem with your test is that the sensor is a heated metal film. It measures airflow by determining the amount the film is cooled for a specific amount of heating. The colder the element becomes, the more air is flowing over it (and the hotter it gets, the less air).
The film is connected to the signal processing circuit by minute, very fragile wires. These wires can be damaged by a number of things, primarily vibration. However, removing the electrical supply to the heater while air is flowing over the element will cause sudden cooling and contraction of very small and fragile parts. So, you can inadvertently create a situation where you can damage a perfectly good sensor. Strike 2.
The next problem with your test is the blind assumption you make that the ECU will stall if you unplug a "good" sensor and will not stall if you unplug a "bad" one. Where did you get that idea? Do you know what the ECU is programmed to do under any specific set of circumstances? Do you know what its ability to learn round degraded sensors is? Have you tried repeating the test, say, 10 times with the same sensor, just to see if the result is consistent and repeatable?
No? Strike 3.
Bottom line: This test cannot, with authority, determine the difference between a sensor that is 100% accurate, 80% accurate or 20% accurate, or indeed one that suffers intermittent drop-outs. These sensors become dangerous to the engine if they are under-reading by little more than 5% under boost, and given that your test can "pass" sensors that are degraded beyond this level, as well as "fail" brand new ones, it simply doesn't work.
[/thread hijack]
Thread
Thread Starter
Forum
Replies
Last Post
