In a turbocharged car whats causes the chattering noise when the accelerator pedal is released?

 

Also, is the noise a good sign or is it causing damage to something?

 

Cheers guys, Dan

The recircs are either not working or they have been disconnnected.

 

 

Jeff TT

What's the benefits from disconnecting them?

Sometimes they get disconnected to stop the "goose honk" noise which is somtimes audible after an induction kit is fitted, there is no benefit, in fact its not good for the turbo`s.

 

Jeff TT

Sometimes they get disconnected to stop the "goose honk" noise which is somtimes audible after an induction kit is fitted, there is no benefit, in fact its not good for the turbo`s.

 

Jeff TT

 

 

What about seperate wastegates like the Trust?

Seperate waste gates are a different thing, usually they are used with big turbo`s so a bigger valve can be employed or some turbo`s just do not include the waste gate as part of their design so need external one`s.

 

Cheers

 

Jeff TT

Seperate waste gates are a different thing, usually they are used with big turbo`s so a bigger valve can be employed or some turbo`s just do not include the waste gate as part of their design so need external one`s.

 

Cheers

 

Jeff TT

 

MMM thanks Jeff its that i'm fitting Greddy TD05 18G turbos with Trust wastegates,and noticed that Mac 1 had uprated springs fitted,and was wondering if i should do the same before fitting.

In a turbocharged car whats causes the chattering noise when the accelerator pedal is released?

 

Also, is the noise a good sign or is it causing damage to something?

 

Cheers guys, Dan

 

or poorly fitted dump valves

Wastegate chatter is a myth. It is compressor stall. See 'Wastegate chatter myth' here for more details.

or poorly fitted dump valves

 

cant help but wonder what alloys are they on your zx?it looks stunning on them wouldnt mind some for mine:o

Wastegate chatter is a myth. It is compressor stall. See 'Wastegate chatter myth' here for more details.

 

 

Correct, but the noise the Dan asked about is the air hitting a closed throttle and the shock wave going back towards the turbo ( compressor ) his use of the phrase "wastegate chatter" is a common mistake but I knew what he meant.

 

 

Jeff TT

Yeh, it just came across as 'dannyfiveforty' thought it actually had something to do with the wastegate. Just spreading the gift of knowledge my friend ;)

Yeh, it just came across as 'dannyfiveforty' thought it actually had something to do with the wastegate. Just spreading the gift of knowledge my friend ;)

 

Thats cool, easy to forget sometimes when answering post`s that some readers may not be fully up to speed on the terminology etc. so good point.

 

 

Jeff TT

it sound like a big fart

 

and dan, they're BK Racing 333

So, if i was to say my Mercedes Turbo Diesel was sometimes (not all the time) making this noise "wastegate chatter"... what would that point to? It is a completely standard car...

Diesel

:hurl:

...............seriously, don`t know.

 

Jeff TT

I thought it was when not enough air can escape through BOV's or whatever you have, so excess air goes Back through the Turbo (the wrong way) and is obviously uber bad for the Turbo!Caused by too much boost!

Is there a difference between Turbo chatter and Wastegate chatter or is it the same thing just different names for them?? alot of older Saab's have Turbo Chatter by owners cranking up the boost too high! Kills the life of the Turbo!\

 

OR as previously stated BOV or REcircs not working (IE nowhere for air to escape) or could be the wrong type of BOVS

Edited December 3, 200817 yr by Munny975

It only does it sometimes, and there is no pattern (i.e cold weather etc)

 

Mercedes Benz have had the turbo apart and said it is as new with no wear, and there are no boost leaks...

 

The sound itself does NOT bother me, Im just concerned as to whether or not it is going to damage something...

Sometimes they get disconnected to stop the "goose honk" noise which is somtimes audible after an induction kit is fitted, there is no benefit, in fact its not good for the turbo`s.

 

Jeff TT

 

So if goose honk(does this cause damage) is evident at air filter upgrade bov's would cure it?

It only does it sometimes, and there is no pattern (i.e cold weather etc)

 

Mercedes Benz have had the turbo apart and said it is as new with no wear, and there are no boost leaks...

 

The sound itself does NOT bother me, Im just concerned as to whether or not it is going to damage something...

 

How are they checking for wear though? By sight alone? could be that the turbine wheel is unbalanced after reading the posted article? Something is not right as there are no throttle bodies on a derver! maybe the compressor veins are all unbalanced? only needs to be a few thousanths of an inch out and when it's spooling up is when it's noticable...but not by checking for wear by sight alone ;-)

 

from same article;

"Surge can occur on diesels when the turbo is attempting to pressurize the air at a higher pressure ratio than the compressor wheel can flow at a given speed. Diesels have no use for a Blow off Valve as they do not have a throttle plate"

Goose honk doesn't cause damage, it's just bloody annoying.

When people get goose honk they useually fit bovs (dump valves) because the other choice is fitting new recircs which are double the price and will probably give up a few years down the line anyway. Recircs were designed to work with the standard air box. It's like everything with this car, you change one thing, you throw a stone in the pond, you will get ripples.

i love the sound.

 

purposly done it on my car (removed the re-circs)

 

everyone deos it on the S14,

 

 

its the sound of the air blowing back against the fins on the turbo.

(like then you blow into a fan)

 

theory is its not good (aparently)

Trying to stop or slow down something that is naturally rotating is never a good thing.

Thanks for all your help guys, basically what you are saying is its the turbo blades that are taking the stress when I hear this noise...

 

Do you think if I somehow had the boost pressure decreased it would help...?

why dont you like the sound?

 

its a turbo car its all part of it :smash:

omg, why dont you guys get this, that chattering noise is bad, very bad, i dont know about diesel engines so i cant comment on that but on a petrol it doesnt mean you have a boost leak or whatever it means:

 

eigher the recircs are malfuctioning or your bov's are closing too quickly or you have fitted them backwards and blocked off the wrong pipe!

 

when yyou let off the throttle on boost the excess air in the system has to go somewhere. Normally it would go through your standard recircs and back into the intake (recycled if you will). If there is a problem like the ones said above the air doesn't have anywhere to go and will try to escape back through the turbo (which is still spinning one way) and forces it to stop spinning so it can escape, which is the noise you can hear (wastegate chatter/turbo chatter).

It is causing wear on the blades and should be avoided unless you want crappy turbo's.

 

When they say that it is caused when the boost is turned up its because standard recircs can only handle so much air and are usually made from plastic.

The zeds recircs are very good metal items and can handle alot of boost

 

HTH