car making weird noice when driving??

[whatchain]

just drove from chch to piction in my gc8, although im almost deaf from the sound of the exhaust... i notice there was a whistle like sound coming from the car\'s engine bay when i was driving it the whole way. i can only hear it when im driving between 90 to 100k in 5th gear. at first i thought it was the music, but then after listening to it for a while, im sure its the car thats making it. just wondering if any1 knows if it\'s the sound of the turbo or is it something else? the car drove all the way up with no problem at all, apart from the sound. also, since fitted the catless downpipe, when i lift off the throttle at 3000rpm, it makes the same sound as a butterfly bov.. except my bov is not a butterfly bov.. is that normal aswell?

[ADIKT]

whistle sounds will most likely be boost leak somwhere.. it will probably be making same noise in all other gears. you just wont be able to hear it.

Butterfly bov/no such thing.

it is compressor surge. put stock bov on with it plumbed in. it will fix this

[whatchain]

shit, i drove for 4 hours with that.... i will check all the boost lines when i get b home. hope that fixes it. this is the sound my bov makes when i shift at 3k rpm (at 0:06)

, but if i shift say at 5000rpm, it goes back to a loud pssshhhhhh sound.

[Timmah]

 whatchain said:

s***, i drove for 4 hours with that.... i will check all the boost lines when i get b home. hope that fixes it. this is the sound my bov makes when i shift at 3k rpm (at 0:06)

, but if i shift say at 5000rpm, it goes back to a loud pssshhhhhh sound.

Yup compressor surge. BoV is set too hard. Soften it or put the stock back on. When you shift at 3k, there woudn\'t be enough pressure to open the BoV, but at 5k there is.

[whatchain]

 Timmah']

[quote name='whatchain said:

s***, i drove for 4 hours with that.... i will check all the boost lines when i get b home. hope that fixes it. this is the sound my bov makes when i shift at 3k rpm (at 0:06) url]

[/url], but if i shift say at 5000rpm, it goes back to a loud pssshhhhhh sound.

Yup compressor surge. BoV is set too hard. Soften it or put the stock back on.

was looking at putting stock 1 back on but the 2 pipes for it cost around $170 from armstrong! ouchy

[Timmah]

 whatchain']

[quote name='whatchain said:

s***, i drove for 4 hours with that.... i will check all the boost lines when i get b home. hope that fixes it. this is the sound my bov makes when i shift at 3k rpm (at 0:06) url]

[/url], but if i shift say at 5000rpm, it goes back to a loud pssshhhhhh sound.

Yup compressor surge. BoV is set too hard. Soften it or put the stock back on.

was looking at putting stock 1 back on but the 2 pipes for it cost around $170 from armstrong! ouchy

Surely a wrecker will have the pipes for a lot less. If your BoV is adjustable, just soften it up.

[whatchain]

ok, will try that first... any idea how much i need to soften it by??

[Timmah]

 whatchain said:

ok, will try that first... any idea how much i need to soften it by??

Best to just have the car idle, soften, give it some revs to where the BoV goes off, if it surges, soften some more. Repeat until surge is gone.

[hijacka]

Bov with a soft spring can also mimic the surge sound as the air bounces back, I told ya your new catless down pipe may cause surge as i said thats the reason why most turbo cars have a cat located near the turbo back of the turbo (helps slow down spool when closed throttle) As above the whistling sound you hear is 100% vac leak

[whatchain]

thanks for the reply team, im sure i never heard that sound until i got car back from jon from spec performance.... Or maybe i haven been driving it at a high enough speed... Either way, i will try sort those 2 problems tomorrow. Also the horn has stopped working all of a sudden.. Loving the never ending problems with the car...

[whatchain]

got the horn and downpipe gasket sorted. now, still having the surge problem. hopefully will be getting a stock bov for it in the next few days, hope that will fixthe surge problem!? 1 more thing, i can still hear the whistle/ringing sound while driving at 60-70 90-105ks(roughly).. i have checked and changed most of the lines already. it doesn\'t sound like a leak sound and also when im boosting it, the sound goes away. i think i will getting hijack to look at the car for me when i get b to chch but meanwhile, i would like to try and sort as much as i can. if anyone know anything about a ringing sound while driving, can let me know where its coming from and how to fix. my guess its from the turbo since the cat is gone.?

[boon]

The Mrs\' Mistral whistles but only when its on boost, due to the turbo being on its last legs...