recently my turbos have started to"whistle"(for want of a better word)on acceleration I think I read somewhere that this could be an air leak..?? can anyone shed any light please I recently fitted a new intake could this be related?

Thanks paulr

 

 

 

Paul, if you mean the noise that sounds a bit like the horn/whistle of a boat and occurs only around 0 bar/psi, then it's probably the intake.

This sound is also known as 'the goose-honk' and is nothing to be worried about.

 

Airleaks sound more like a 'whooosh'-sound and you won't get full boost

 

If the sound is more like a whining whistling, then it could be there is something wrong with the turbos itself.

 

-Eric

 

Paul,

 

Check for Vacuum leaks especially on the intake hard pipe that go to the turbo, Vacuum line nipples on these hard pipes are prone to leakage and splitting, If poorly installed (like mine were - Electrical tape, now there is a insulating medium for ya) the nipples can get sheared off.

 

If you fail to track down the leak in the vacuum system, then you could be looking at slight damage to a compressor wheel in one of your turbos. The Sound could be the turbulance being caused by a damaged fin.

This is usually the sound associated as whistling but without hearing the sound myself i would be highly cautious about jumping to this conclusion. As repair will be costly.

 

Check for secondry signs, such as fluctuating waste gate operation, loss of boost etc to help in your search for any leak.

 

Good Luck

 

Z ya

 

Nico91TT

 

 

Nico,

i'm curious ;) how do you check for fluctuating waste gate operation ?

Craig

 

checking for waste gate fluctuations?

in answer to how you check ? it simple, you do it carefully lol.

 

here is a pretty good article on turbos and troubleshooting, good luck

 

http://www.avweb.com/articles/turbosys.html

 

Wastegate problems by warren sheehan (lol)

The other most common cause of turbo-system problems, besides induction leaks, are problems with the wastegate and wastegate actuator. It makes perfect sense that the wastegate would be one of the most problematic parts of the turbocharging system, because it performs such an unenviable job: regulating the flow of incredibly hot and corrosive exhaust gases.

 

Most wastegate problems are of the "sticky wastegate" variety in which the shaft on which the wastegate butterfly pivots gets "coked up" with byproducts of combustion (a nasty concoction of lead, carbon and sulfur) to the point that it no longer opens and closes smoothly when commanded to do so by the wastegate actuator. Another somewhat less common cause of "sticky wastegate syndrome" occurs when the wastegate actuator itself starts to bind as a result of the accumulation of oil-borne deposits, O-ring deterioration, and/or scoring of the actuator cylinder.

 

Whatever the exact cause of the sticky wastegate, the result is that the constant series adjustments commanded by the turbo controller-which are normally executed so rapidly and smoothly that they are unnoticeable to the pilot-become jerky and erratic. The result shows up as abnormal MP fluctuations, especially during periods of constant wastegate movement such as climb, descent, and flight in turbulent air.

 

It's easy to confuse the erratic MP fluctuations caused by a sticky wastegate with the unregulated MP fluctuations caused by bootstrapping, but they're really quite different if you know what you're looking for. Bootstrapping (due to a fully-closed wastegate) is a condition that predictably occurs at high altitude and low engine RPM, and which can be made to disappear at will by increasing RPM a bit or descending a bit. On the other hand, erratic MP fluctuations due to a sticky wastegate generally occur at various altitudes and RPM settings, and are most obvious during changes in altitude, power settings, and airspeed (all times when wastegate adjustments are most likely to be commanded by the controller).

 

If you suspect you might have a sticky wastegate, it's easy to check in the shop. Simply remove the oil line that runs from the engine oil pump to the wastegate actuator. Hook a source of adjustable air pressure to the oil inlet port of the actuator-an ordinary cylinder compression tester is ideal for this purpose. Now simply watch the wastegate assembly as you slowly and repeatedly vary the air pressure from zero to 50 PSI and back. As air pressure reaches 15 PSI or so, the wastegate should start to close smoothly, reaching its fully-closed position when the pressure reaches around 50 PSI. As you back the pressure down towards zero, the wastegate should open smoothly. Watch for any signs of jerkiness or binding as you exercise the wastegate in this fashion. Any tendency to stick should be obvious during this test. Also make sure the wastegate butterfly opens and closes fully, a total movement of approximately 90 degrees of shaft rotation.

 

 

 

I was gonna say just check for rough turbo boost curves and also check for excessive over boost or choppyness at Max Boost.

 

However Warren's Fighter Pilot thing was more ammusing.

 

Altho i would like to see someone attach a air line to the waste gate actuators with the engine in the car. It is a good way to test tho, if you can get to them .

 

Z ya

 

Nico91TT

 

 

 

 

 

Last time my turbo's started to whistle I thought it sound great!!

 

One of the damn things seized a week later.

 

:-(

 

Steve

 

as always thanks for your replies ,very helpful..

paulr