Alfa Romeo Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
525 Posts
Discussion Starter #1
Hi have noticed recently on my 1.4 ma under hard acceleration as the revs build I can hear a hissing sound from the turbo.

its not especially loud but noticeable with radio off and window open which maybe why I've just noticed it as only got the car last year, doesnt feel any loss of power and the boost gauge fills up ok.

Never had a turbo before and just wondered if they do make this noise normally.

Thanks for any replies

Sent from my D5103 using Tapatalk
 

·
Registered
Joined
·
258 Posts
Hi have noticed recently on my 1.4 ma under hard acceleration as the revs build I can hear a hissing sound from the turbo.

its not especially loud but noticeable with radio off and window open which maybe why I've just noticed it as only got the car last year, doesnt feel any loss of power and the boost gauge fills up ok.

Never had a turbo before and just wondered if they do make this noise normally.

Thanks for any replies

Sent from my D5103 using Tapatalk
Sounds quite normal to me, my 1.4MA G was the same. Noise is only noticeable with the windows down, now I have got a 1.4MA Jeep Renegade & it has the same characteristic.
 

·
Registered
Joined
·
38,703 Posts
Sounds normal to me as well.

I have had this on all of the turbo cars I have owned, including my Diesel G.
 

·
Registered
Joined
·
436 Posts
have this on my qv and thought it was odd.i don't notice when window is open but sounds like air through vents when window is up
 

·
Registered
Joined
·
525 Posts
Discussion Starter #6
I have something similar to that on passenger side, think its wind noise from somewhere, maybe the window seal isn't quite as tight as it should be.

Noise I was referring to is definitely from turbo or at least engine bay somewhere

Sent from my D5103 using Tapatalk
 

·
Registered
Joined
·
38,703 Posts
The turbo whistle should be quite faint. If is is loud or if you get other noises such as screeching then you have issues.
 

·
Registered
Joined
·
36,851 Posts
My AC is noisier than I remember it. Had it regassed and apparently no signs of leak when pressure tested.
 

·
Registered
Joined
·
8,786 Posts
vacuum tested or pressure tested? AC should operate in complete silence.

Anyway, leaks don't always show like that unless they used nitrogen laced with hydrogen. H2 being the smallest molecule on earth, it needs only avery small leak to escape, and the technician has about 15 minutes to find it with an H2 detector.

UV dye is often the most reliable way to locate a slow leak. 9 times out of 10 it's the condensor though.
 

·
Registered
Joined
·
38,703 Posts
Actually Helium molecules are smaller than hydrogen. :p

Hydrogen is a diatomic molecule hence H2, and these are larger than Helium molecules.

At work we use Helium detection to find leaks for this reason. Another good reason is that it is inert and much safer to use.

Checking the AC shouldn't be too difficult with a leak detector and a bottle of helium. (The same stuff used for baloons will be fine), all you would need to do is pressurise the system slightly with it and then use a sniffer probe to go around the system to find a leak.

You can rent helium leak detetors from places like this West Technology UK custom vacuum engineers, high vacuum,rough vacuum,leak detection,leak detectors
 

·
Registered
Joined
·
464 Posts
Same in my industry for things like holed foils in the contamination monitor arrays, when I used to work in Instrumentation.

On my 156 years ago (soon after its remap) I once blow the inlet hose that connects to manifold after some spirited driving.
Easy to tell the difference as you accelerate with the turbo whoosh between gear changes especially.
Perhaps made that bit more audible with the remapped engine!!!
Still plenty of duck tape over the inch long split and light footed accelerator use until the new hose arrived. No problems encountered since.
 

·
Registered
Joined
·
464 Posts
Hopefully nothing for yours but if you want to try checking this was how I found the split hose.

I just squeezed along the hoses on inspection until split found.
Undoing the more easy to reach jubilee clips helps until found; which happened to be out of sight, but going by feel pick up easily.
 

·
Registered
Joined
·
525 Posts
Discussion Starter #13
Had another listen to mine this morning it isnt very loud, the wastegate when you lift off is louder just as an example. and seems to do it between 2500-3500 revs then cant hear it at higher revs

Sent from my D5103 using Tapatalk
 

·
Registered
Joined
·
8,786 Posts
Actually Helium molecules are smaller than hydrogen. :p

Hydrogen is a diatomic molecule hence H2, and these are larger than Helium molecules.

At work we use Helium detection to find leaks for this reason. Another good reason is that it is inert and much safer to use.

Checking the AC shouldn't be too difficult with a leak detector and a bottle of helium. (The same stuff used for baloons will be fine), all you would need to do is pressurise the system slightly with it and then use a sniffer probe to go around the system to find a leak.

You can rent helium leak detetors from places like this West Technology UK custom vacuum engineers, high vacuum,rough vacuum,leak detection,leak detectors
Helium is getting rare, there's advisories against unnecessary use. but you're right.

R-134a detectors also exist, so as long as the ac still works you could use them aswell.
 

·
Registered
Joined
·
38,703 Posts
When I used to work in the superconduction magnet industry we used to quench Magnets to atmosphere, and tonnes of the stuff would be lost.

It was an expensive waste, but they didn't seem to care. :rolleyes:


It makes me laugh that helium is so rare on earth yet it is the second most common element in the universe.

At my current work we do residual gas analysis, and to be honest you could use pretty much anything to leak test things with it. Of course the smaller the molecules the smaller the leak rates you will be able to detect.
 
1 - 16 of 16 Posts
Top