Outer Limits 4x4 Board

hey just wondering if anyone knows why my bros 2H turbo cruiser is making blow off valve sounds on gear changes, it doesnt hav a bov and never used to make this sound.

its very wierd and has me stumped



Cheers

So it's turbocharged?

If so maybe a leak in the intake between turbo and butterfly.

Otherwise maybe the clutch linkages need some WD40

wastegate on the turbo?

SCANAS wrote:wastegate on the turbo?

X2

My 1HZ turbo makes a kinda blow off sound on gear changes.

yes its a turbocharged


has a brand new wastegate thou, priity sure it shouldn't b making these sounds

New exhaust too?

You couldnt hear mine till i fitted a straight thru exhaust. The sound doesnt indicate anything wrong, its just the wastegate opening.

Usually your exhaust gases pass through the turbo which quietens the exhaust down significantly. When it goes through the wastegate, it bypasses the turbo and is therefore louder.

Where a BOV releases the fresh clean air (either to atmosphere or back into the system) The wastegate is on the exhaust side.

The wastegate will open when the set boost pressure is reached, it will stop turbo from overboosting. If you drive steep hill and are at max psi, you can hear the wastegate open, and stay open.

All im getting at is, the sound is normal.

Mike

wasfishing wrote:hey just wondering if anyone knows why my bros 2H turbo cruiser is making blow off valve sounds on gear changes, it doesnt hav a bov and never used to make this sound.

its very wierd and has me stumped



Cheers

mate it is compressor strge (like a VL)...it is the air bouncing from the butterfly back to the compressor

http://www.youtube.com/watch?v=JOT-2a8WfRQ

didnt think diesels got compressor surge?

mike_nofx wrote:didnt think diesels got compressor surge?

yep they do

that noise is the air going back through the cooler. a deisel wont do without huge boost cos im pretty sure most dont have a butterfly anyway? And the reason petrol turbos do it is cos the butterfly snaps shut. check if your inlet manifold is tight or maybe leaking. but either way itll make some noise maybe the new wastegate is giving it more boost, do you know what the actuator is set at.

HUSSLN wrote:that noise is the air going back through the cooler. a deisel wont do without huge boost cos im pretty sure most dont have a butterfly anyway? And the reason petrol turbos do it is cos the butterfly snaps shut. check if your inlet manifold is tight or maybe leaking. but either way itll make some noise maybe the new wastegate is giving it more boost, do you know what the actuator is set at.

there is about 2 types of noisey a deisel can make depending on the inlet

noise 1
http://www.youtube.com/watch?v=eYHWCs3W-0U

noise 2
http://www.youtube.com/watch?v=Vs9ERhHTlmU

second one is killer, puts alot of vlt doses to shame. common rails have a butterfly yeah? again 20 psi to do it.

kinda sounds like thefirst youtube link, but it never used to make this sound??? and its not because of the enw actuator we changed that coz it wasnt holding boost

did you add a snorkel recently?

I just did both the snorkel, and 3" exhaust including Dump pipe, and you can hear the same sound your describing i don't think its anything to worry about, it's just your waste gate opening.

nope haven't changed a thing just randomly starteded happening after a hour long drive

wastegate doesnt open on gear changes. it regulates boost by bleeding it off, if anything during a gear change its closing. Dont worry about all this dose/flutter stuff you wont be making that noise without a decent cooler and some intake gear. Air passing back thru the intake on gear changes is nothing to worry about. it has to go somewhere.

at the end of the day its nothing to worrie about all turbos flutter make noises what ever you want to call it if your worried about it take it to a respectable deisel mecanic and see what they say