Owl noise

[JaamesVRS]

I know this had been covered so many times with no real answer

 

I've been told it's only the Miltek that makes the noise due to the downpipe design however some people say it's due to decat and back box delete, I have both to go on the car and want to know if it should make the noise...

 

some hate it some love it but it's the closest we're going to get to turbo chatter on a diesel.. apart from the VKLR boys

[sepulchrave]

Only turbos with a wastegate can make the chatter, which means no VNT's, you can make the noises with your mouth, no-one will think it's silly, practice makes perfect, it's kinda like beatboxing 

 

https://www.youtube.com/watch?v=9IkzY0JUo_M

Edited 31 May, 2017 by sepulchrave

[JaamesVRS]

Yeah sorry I meant the VNTs lol, curious to why apparently only certain exhausts make the cooooo... how true that is or not?...

[sepulchrave]

It's more to do with how quickly your VNT feathers (Owl, feathers, geddit), the sound is produced by the exducer cavitating as the vanes open up to prevent the turbo overspeeding.

I believe a plain pipe from the turbo back would be noisiest, no-one who's spunked hundreds on an aftermarket exhaust will ever admit that they've just wasted their money, but...

[JaamesVRS]

So if the car makes the infamous noise does that mean the turbo is healthy? Unhealthy? Or either? 

 

Fired the car car up earlier with down pipe and centre section fitted, rear section wasn't on at this point as still need to get the old backbox off over the axle! (Ball ache) and couldn't hear the noise, personally I like it, others don't I know. Is it more when the car is under load opposed to stationary? 

[sepulchrave]

1 minute ago, JaamesVRS said:

So if the car makes the infamous noise does that mean the turbo is healthy? Unhealthy? Or either? 

 

Fired the car car up earlier with down pipe and centre section fitted, rear section wasn't on at this point as still need to get the old backbox off over the axle! (Ball ache) and couldn't hear the noise, personally I like it, others don't I know. Is it more when the car is under load opposed to stationary? 

 

Yes, engine must be loaded up, it'll happen when you come off the loud pedal to change gear or just coast down.

[JaamesVRS]

Ahhh okay that will be why then 

 

so so if the car does owl, is it a good thing or a bad thing? Or neither? 

[sepulchrave]

You're just hearing a noise that would normally be silenced in a standard system, so neither.

[JaamesVRS]

Oh okay cool! Just read on another page that when 95% of people replaced their turbos after they went pop the noise stopped so I wondered if the noise was a sign of a failing turbo possibly 

[JaamesVRS]

Decat and straight pipe with a tip fitted, no coo! Must depend on the car or exhaust type surely 

[Xoij]

I have a full piper system, 2.5" downpipe, decat 0 boxes.. You don't get a mega COOOOOOO but you can hear a muffled coo, I guess it's down to turbo setup. I think the miltek downpipe reason is a myth imho.

[JaamesVRS]

I've read on a few other forums Turno condition plays a big part, some people said that they're car used to Cooooo like mad, changed turbo to a new/recon and it stopped.. apparently if your car doesn't Coo the turbo is in good condition, mine at 1800rpm goes coooo very slightly have to listen out for it, others I've heard really go COOOOOOOOOO for ages and really loud too... guess it's a good thing it doesn't coo! But I do love the noise 

[Citigouk]

22 hours ago, sepulchrave said:

Only turbos with a wastegate can make the chatter,

 

 

Something like this? Yes in a smart

 

 

[JaamesVRS]

This is the noise I'm after!

 

 

[Titanium_Man]

Sorry, but it's chavvy. Don't waste your time or money sounding like a burk, spend your dosh on something useful like decent suspension or brakes. 

[JaamesVRS]

One mans junk and all that. 

 

Just changes the the sound up a bit from Fairground generator mode  

 

decent suspension and brakes are in the pipe line, don't need the best in the world, it's a daily.. got the Race car for that, thrown enough money over the years into it! 

[Minjukas]

On 5/31/2017 at 18:36, JaamesVRS said:

I know this had been covered so many times with no real answer

 

I've been told it's only the Miltek that makes the noise due to the downpipe design however some people say it's due to decat and back box delete, I have both to go on the car and want to know if it should make the noise...

 

some hate it some love it but it's the closest we're going to get to turbo chatter on a diesel.. apart from the VKLR boys

My vRS with back box delete (mufflerectomy) does make the owl noise at around 2000-2300 RPM probably when it builds up the pressure. You can hear it, but it is muffled my guess is by a cat

[JaamesVRS]

See mine is straight through just a tip, and decat too. Got the system silly cheap for brand new! Got a 600 quid stainless cat back on the race car, wasn't interested in spending silly money on one for the daily derv. My only other guess is possibly back pressure? As the straight pipes lack back pressure may stop the Cooooo, where as systems with a box/restriction generate more back pressure thus making the noise. Mufflerectomy still uses the box/cat, miltek also has a box in the system, both of these generate the Coo so it seems 

[stevobeavo]

I have the miltek system with a de-cat. No coooing noise at all. Just a nice quiet exhaust when round town and a roar when full throttle with a bit of a rasp at the last 500rpm or so.

[JaamesVRS]

Sounds just like mine then to be honest... must be to do with the condition of the turbos/if the veins are sticking creating the Cooooo or if they snap shut then no coo, all I can think of anyway

[Minjukas]

2 minutes ago, JaamesVRS said:

See mine is straight through just a tip, and decat too. Got the system silly cheap for brand new! Got a 600 quid stainless cat back on the race car, wasn't interested in spending silly money on one for the daily derv. My only other guess is possibly back pressure? As the straight pipes lack back pressure may stop the Cooooo, where as systems with a box/restriction generate more back pressure thus making the noise. Mufflerectomy still uses the box/cat, miltek also has a box in the system, both of these generate the Coo so it seems 

 

I don't know much about exhausts (or cars themselves) but this is what I did to mine and it Coo's quietly at around 2000-2300 rpm.

[JaamesVRS]

This is the system I have on mine, should coo if anything! However it doesn't must be due to turbo