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General Information => Troubleshooting => Topic started by: Smokey Eddy on March 03, 2009, 03:33:40 am
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When you're boosting in excess of 15psi and you release your foot off the smoke pedal and you hear that incredible WOOOOOOOOOSSSSSSSSSH sound, is that compressor "surge"? and can it be harmful? what exactly is making this enormous sound?
with just a 2.5" down pipe that ends at the shifter its a super loud wooo-er-ing sound.
There is a bloke on here who has a video of his turbo making the sound in the distance. Mine is way way louder than that. I hope i'm not breaking things?
its t3 and it hit 25+ psi a couple times and that's when the surging sound was loudest (which makes sense)
i have an aaz head on a 1.6td MF bottom end everything attached to the head (except the block) has been ported and polished.
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I think turbo surge is more of a barking sound and yes it is very bad. I'm pretty sure the sound you hear is normal as mine makes it too.
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omg my turbo is blowing up cause it makes noise, turbo bark, better take turbo off, throw away, turbo bad :wink:
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omg my turbo is blowing up cause it makes noise, turbo bark, better take turbo off, throw away, turbo bad :wink:
RACIST!!!!!
I love being random... lmao ED your car is gooood :P Run It HARD lol
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sooooooo
it has nothing to do with this oil leak i have? I thought it was from the oil pan but now (removing the exhaust) I see an oily mist all over everrytthingg...
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an oily mist!? like.. is it coming from .... where is it coming from? have you narrowed it down yet?
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I just found it this evening =)
It was coming from the oil cooler sandwich plate sensor. I tightened it a bit (its a 24mm for reference) but i think it's stripped out.
Good thing i have a sandwich plate for an oil cooler! Phew. Just gotta drill and tap it PRE cooling.
it would dribble down the block and disperse because of the flow of the wind from moving. And it would just mist off of everything.
I'm still having turbo issues though but its boost related not necessarily turbo related. I'm glad the WWWWWWHIIIIIIIERRRRRRRRR sound is okay :P
definitely doesn't sound alarming like barking.
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I think the sound your talking about is the backfire when you let the pedal go.The pressure built up has nowhere to go so it tries to escape out the compressor.
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now THAT makes sense...
does one want to avoid this? I would imagine so...
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where are you Tom when we need you
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compressor surge is a big problem with gasser motors, when the throttle is closed quickly there is a huge spike in pressure as there is nowhere for the air to go, this causes the turbo compressor to try to drive backwards, very bad for the turbo it can break the shaft.
that is why gassers have blow off valves or diverter valves, to relieve this pressure before it breaks something.
on a diesel letting off the throttle changes nothing about where the air can go, there is still an unobstructed path into the cylinders.
the noise you hear is the compressor de-accelerating because the exhaust turbine is not driving as hard due to less exhaust gasses.
don't worry about it, surge is not a big issue in diesels.
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don't worry about it, surge is not a big issue in diesels.
Really?
I have a couple turbos that would disagree.. Snapped shafts, ground down compressors etc etc.
Where I do agree it's not as a big of a deal on diesels it's still a issue and it's an issue that can destroy your turbo.
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how much boost were you running?
diesels don't have the inherent tendency to deadhead the turbo the way a gasser does when the throttle plate closes so it should be much less of an issue.
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if your boosting 20psi the cylinder may not inhale all the pressure left therefore it tries to escape out the inducer.
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how much boost were you running?
Just a coulpe lbs :twisted: :twisted: :twisted:
Well ok maybe a tad more than that but as dillenger1 pointed out throttle plate or no if that suka is pushing 20 psi and you let off the fuel its still pushing 20 psi for a sec. That air has to go somewhere and back past the compressor is the sound you hear. Not good for the turbo either way
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thanks for all the discussion Fellas! I'll be sure to "ease" off the throttle from now on =)
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how much boost were you running?
Just a coulpe lbs :twisted: :twisted: :twisted:
Well ok maybe a tad more than that but as dillenger1 pointed out throttle plate or no if that suka is pushing 20 psi and you let off the fuel its still pushing 20 psi for a sec. That air has to go somewhere and back past the compressor is the sound you hear. Not good for the turbo either way
I still don't quite understand why the pressure would back up into the turbo tough because the pressure is a straight shot into the combustion chamber through the intake valves which are still working and the exhaust valves also just no fuel being injected. I am new to turbos though but I just don't understand that part.
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the impeller no longer has that force (energy) coming from the compressor side of the turbo and just milliseconds ago it DID have LOTS of energy pushing 20psi of boost (or what ever it is) towards the valves. So, when that force goes away. It's the path of least resistance in comparisson to closed intake valves (or say even just 1 intake valve being open?).
So, it equalizes and escapes.
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i myself wouldn't be too concerned unless running more than 20 psi. things that i would do to minimize this, is just completely letting off the throttle after the hard acceleration, unless in an emergency braking situation. leaving the engine in gear will also help reduce the stress because the engine will be consuming more air.
running 30 psi might pose some issues though... then you might want a BOV.
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I know what compressor surge/stall sounds like in a turbine engine it sounds like a series of loud bangs.
Radialcompressors as whe have in our turbo´s is not so prone to do this, but when running high boost you might get the problem when letting off the throttle however I think it is only for maybe a 100/second or so until the pressure has decreased.
Best regards / Tommy
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I'm not at all convinced that the sound described has anything at all to do with residual pressure in the intake, in fact I don't believe it has anything to do with the intake side of the turbo at all. The pressure on both sides of the turbo will drop at virtually the same time due to the unthrottled nature of the engine and the fact that the engine is ingesting the same amount of air as before. I am convinced that the noise described is simply the effect of the turbo basically being on overrun. When the pressure on both sides of the turbo dissipates faster than the turbo slows down, the fins are then pushing the air in the turbo rather than the other way around and the noise results. This is especially apparent with an exhaust that has no back pressure. Add even a small amount of restriction and the noise goes away.
Andrew
those were my thoughts exactly!
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Ahhhhhhhhhhh!!!
YES!
Because it only happens with BIG wide open exhaust! with my ressonator and muffler it didn't do it at all. (it also didn't make any boost though :evil: )
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with a restrictive exhaust it is still happening, you just cant hear it.
I wouldn't worry about it, I know I dont
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I know I dont
Lolz! :lol:
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the impeller no longer has that force (energy) coming from the compressor side of the turbo and just milliseconds ago it DID have LOTS of energy pushing 20psi of boost (or what ever it is) towards the valves. So, when that force goes away. It's the path of least resistance in comparisson to closed intake valves (or say even just 1 intake valve being open?).
So, it equalizes and escapes.
Thanks for the answer, that does make sense and I can see that happening now.
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on another note im almost done changing all my HUD lights to 48k millicandela red LED's i found on Ebay. Did that over the weekend :P
Here is the thread for the OP but im changing it so you can do the job with just a rotary tool (dremel) and some LED's, glue, wire, solding iron, and a couple resistors.
IE. you don't have to get that special plastic machined or laser cut.
http://forums.vwvortex.com/zerothread?id=4206297
You can follow the OP's post there but instead of ordering your own pieces you can just paint the backing black. Anyways, my post will be up shortly. Hopefully after tomorrow in the DIY (monday, march 10th. Wed at the latest, i need to put that dash back together! I also finally got a fuse box for my GP's Vince style. Yay! Exciting.)
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where are you Tom when we need you
Sorry was at the autorama all weekend and haven't been on here. I agree with andrew its the exhaust side making the noise. Its the turbo changing speed quickly. Surge normaly happens at low rpm under high load.
http://www.youtube.com/watch?v=mHmdO350xcY&feature=PlayList&p=ECAD9EEDD2186EA0&index=0&playnext=1
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That dog barking sound is NOT what im trying to describe... I'll look for the post... I can't believe he hasn't posted his video yet. He's a really turbo/exhaust noise savy guy...
http://www.youtube.com/watch?v=JP67FLK-xBM
0:22-0:24
THERE IT IS!!!!!!!!!!!
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@ 0.30 or this. To me that is an awesome sound but not bad.
http://www.youtube.com/watch?v=Vzm-j4k9tNI&feature=related
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yeah, 0.32 too.
So that sound isn't ... harm being done to the turbo? phew. It was deafening inside the car.