Choo choo

[DeeTurbo]

When I'm changing gear or coming off the gas under load there is now a choo noise that has developed. 

I was thinking it might have been an exhaust leak but now I'm thinking the exhaust system on the car shouldn't be that restrictive as it hasn't got a cat and only two mid boxes. Could there still be enough back pressure to make the leaking exhaust noise audible with a choo noise? 
 
I've got a feeling it's leaking from the wire gauze gasket that's before the down pipe.

[Steve1990]

That cho cho it turbo building up presure then wen you let off the throttle all that boost has no were to go so it goes back through turbo causing that cho choo. Turbo cars normally dont need back pressure you just want as much of the exhaust gasses to go in and out the turbo as fast it can hope this helps

[DeeTurbo]

Yeah it does sound like a very very quiet dump valve.

The thing is it never use to make that noise before and I don't here it on the estate or my girlfriends 206 HDI.

[JTaylor2005]

What steve1990 only applys to petrol cars and very rarely possibly modern diesels that have a throttle plate. These cars dont so it cant be that

[Steve1990]

Have you got a k and n filter exhaust or owt like that does ot do it every gear change or just as boost it gets to its peak before wastegate opens it would do it then. If you suspect exhaust leat get a old rag an hold it over exhaust while a friend listens for the leak

[Seb_Ryan]

What steve1990 only applys to petrol cars and very rarely possibly modern diesels that have a throttle plate. These cars dont so it cant be that

Its a simular noise though, mine used to do it at about 2k if you was on full throttle then pushed clutch in. Im pretty sure its compressor stall? Not good for it either way but sounds funky lol

[Steve1990]

What steve1990 only applys to petrol cars and very rarely possibly modern diesels that have a throttle plate. These cars dont so it cant be that

Its a simular noise though, mine used to do it at about 2k if you was on full throttle then pushed clutch in. Im pretty sure its compressor stall? Not good for it either way but sounds funky lol

Mabey im wrong but my 1.9 dturbo with mfic d filterd ( i know thats not good for it lol) with 30 psi and welded wastegate use to choo choo like f##k

[Piggy]

it will choo choo then go bang bang boom

[pro_steve]

Sounds like compressor stall, basically you're boosting a lot and you let off the power and there's nowhere for the air to go. Have you upped the boost a lot? Does it on my car but I run 1.8 bar of boost.

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Like this noise? https://www.youtube.com/watch?v=_61PN7Y_w1g

[DeeTurbo]

The boost is standard and I'm running one of your maps Steve.

I doubt it's a compressor stall as it's not that loud. I'd say it's barely audible, I'll see if the mic on my phones camera picks it up tomorrow. You hear it most in the drivers seat, if I'm a passenger you can't make it out.

I've got a feeling it's an exhaust leak as it only started happening after I adjusted the back box as the centre part was knocking on the heat shield.

[DeeTurbo]

Not the best video but you can hear it chooing a little.

I think I'll be changing the fire ring, mid section and to a proper back box this weekend. Probable Bosal stuff.

Also the ignore the EML, TPS issue that seems to be sorted now but waiting to see if it reoccurs before clearing the codes.

http://youtu.be/6Sap-wQzQpw

[mr_fish]

can just about make it out on the video.

is it like this?

[silverzx]

Pigeons get the b1tches yo. Chooooo.

[pro_steve]

Doesn't sound great to me, take the turbo inlet pipe off and check the turbo for shaft play, could be on its way out. Also check all the other pipe work is connected properly.

[DeeTurbo]

Cheers, will do.

One question, would the play be in the in and out axis or up and down?

The car does't feel as sprightly as it use to and compared to the two other HDI's I've got access to but it's still boosting up to 15psi.

[Piggy]

Both possibly

[Poodle]

The in and out play is more of a problem, some of the up and down is just tolerances and designed to be taken up by the oil in use.

[pro_steve]

A bit of up and down is ok, but obviously if it's more than a couple of mm there's a problem. It should be quite tight axially, so if you get a lot of play there it's a good indication the bearings are on the way out. Take a look on youtube, there are a few videos showing what is good and bad.

[Toms306]

The YouTube vids aren't really easy to properly see, I was struggling to interpret turbo servicability for a while. Main points I learnt was in and out is always bad. Up and down is normal until its enough to touch the sides. Without having experience of loads of turbos that's about the best way to check imo.

[Alan_M]

My HDi does this, but when I replaced the seal on the turbo intake pipe (NLA by the way) I checked the turbo for play. Tight as a drum.

Only started doing it after the remap.

[toseland]

Sounds like compressor stall, basically you're boosting a lot and you let off the power and there's nowhere for the air to go. Have you upped the boost a lot? Does it on my car but I run 1.8 bar of boost.

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Like this noise? https://www.youtube.com/watch?v=_61PN7Y_w1g

Me and you are going to be having a conversation about making my car sound like that steve haha

[pro_steve]

Just get a really big turbo and try to make it fit on there. GT20 should be good with a massive intercooler. Might stick one on my van soon, plenty of space behind the engine

[toseland]

already in the process haha

[Poodle]

Steve, i need to talk to you about this, i'll call when i get a spare ten minutes.