turbo/intake whine..?

[08_MS3_GT]

i get the familiar turbo whistle when spooling, but, upon hitting full boost, i occasionally hear a whine. similar to a sort of whine/moan sound that the walls of a house when it is really windy.

i don't mind it, i've just ridden in/driven turbo cars and have only heard it once before, in a stage 3 early 90's audi s4. should i be concerned about turbo failure? i didn't find any threads that discussed this sort of issue.

 

[F430TECH]

How many miles does your Car have? Not many since you are an 08.

I could be your wastgate actuator, the Speed Proteges were notorious for this. I also had a crack in my manifold on the Speed Protege one time that gave off that sound. Funny thing was, I found it, took it to the dealership and said there is a crack in the header, two days later, "we coudn't find a crack", I had to go in ther and physically point it out to them. Instead of removing the heat shield completely they had only pulled it back and inspected the top of the exhaust manifold. Idiots.

It could also be you bearings in your turbo not receiving enough lubrication. Sometimes this causes them to gall which can also result in whine.

Boost leaks could be another source. A crack or leak in the piping that only makes itself apparent when on full boost i.e. fully expanded.

 

[08_MS3_GT]

Thanks for the reply, F430Tech.

My car has nearly 6k miles on it now - essentially brand new.

Maybe I'll have to look it over in an effort to find a boost leak or crack. I don't really suspect lubrication issues, although I should confirm the oil level - the oil itself is Amsoil 5W-30.

Funny thing is, now that you mention the manifold crack, I have noticed that I can sometimes smell exhaust fumes when running at higher throttle for extended periods (windows open). I just figured it was some sort of air circulating from the rear of the car (somehow..), but perhaps it's a cracked manifold?

One other thing - I have an HKS SRI - could it simply be the sound of the intake?

And just to reiterate, it definitely sounds like a stream of air. I had a boost leak on my old car which sounded like a vacuum gone wild; the noise I've observed is very consistent.

How would a failed actuator work? Leak off too much boost? I haven't noticed power loss.

 

[F430TECH]

Failed actuator would yes leak off too much boost as the boost begins to rise. Which essentially is at higher revs. On the old speeds it was a problem with the diaphragm I believe although I could be wrong. Its overcoming the wastegate early and allowing boost to slip by which may cause a whining sound.

But honestly symtoms so far iw oudl say crasked manifold. You havenet washed the car right after driving a long way or sprayed water under the hood to clean the engine bay after a hot drive have you? Thats what caused the protege manifold to crack. It had the cleanest engine bay when I bought it (from a friend no less) but when she had been wasking under the hood with water she had done it while hot and the sudden cooling of the cast iron has caused it to crack.

Whats mods do you have?

My mom and stepdad live in Lake Nebagamon WI (by duluth MN) by the way, I should be up that way over Christmas.

 

[08_MS3_GT]

i haven't sprayed cold water into the engine bay when the engine's hot... though, with engineering a mass-produced car, i would expect mazda to account for thermal expansion/contraction when building parts. yes, cracking can occur, but a lot can be accomplished with proper engineering.

the intake is the only modification on the car; i actually took it out for a 'spirited' drive and found that the noise seems more like intake than a failed part. the car's performance is certainly there - i would expect more turbo lag if my exhaust manifold were leaking off pressure. i'll have to get under the car sometime soon and have a look around.

i'm more in southeastern wisconsin- my job, home, and girlfriend mean that i basically cover a 200mi stretch of freeway down there.

 

[RichB]

I have noticed this whine sometimes too. Do you have a stock BPV? When I installed a Forge BPV the noise went away.

Could a leaking BPV cause this noise?

 

[john blutarski]

I have the same spooling whine too but not at full boost only at partial... maybe holding 5 psi or so.

 

[zaka]

I've also this turbo spooling whine between 2000-2500rpm especially when the engine is still cold! I havn't seen the issue yet
Is it normal or not?!

 

[RichB]

Now that I think about it, I heard the whine especially when the engine was cold as well. Our cars make a lot of weird noises when cold but are smooth as butter when warmed up.

 

[zaka]

Now that I think about it, I heard the whine especially when the engine was cold as well. Our cars make a lot of weird noises when cold but are smooth as butter when warmed up.

Yes, when warmed up, I couldn't hear it! Do you think is because of the cold weather? Or may be because of my ETS TMIC? Because I've installed a the ETS few weeks ago, and I've already checked all clamps!

 

[08_MS3_GT]

I have noticed this whine sometimes too. Do you have a stock BPV? When I installed a Forge BPV the noise went away.

Could a leaking BPV cause this noise?

a leaking BPV seems like a possibility; not sure how it would relate to the car being warmed up or not. i upgraded the valve on my old car when i upped the boost, so i never had any leak issues to diagnose.

that said, other ppl have noted that the Forge unit itself leaks when not adjusted properly - how do they know when it's leaking?

 

[RichB]

other ppl have noted that the Forge unit itself leaks when not adjusted properly - how do they know when it's leaking?

If you have a boost leak, the first thing to check is the BPV.

 

[08_MS3_GT]

idk if i have an actual leak, tho it seems possible that the BPV is leaking given what i've read.

 

[F430TECH]

Everythign is realted to how warm te car is. When the car gets warmsd everything expands, thus sealing a little bit better...

I would put the Forge BPV on it and see what happens...

 

[RichB]

so if it's not a leak then what?

 

[08_MS3_GT]

forge BPV installed; i'll have to check again for the noise although winter weather has recently arrived in full force and 'spirited' driving is not as straightforward.

 

[F430TECH]

hahah you guys want to hear something funny...

I now have a test pipe and Forge BPV installed about thousand miles ago(only mods so far), and I now have this sound....at 6500 miles...even when warm and mine occurs in the high end of the rev range. My old Mazdaspeed Protege used to make this sound and I suspected bad Wastegate actuator, cracked manifold, or the bearings on the turbo going out. Personally I hope its none of these.

Am going to pull the Forge BPV tonight and examine it for leaks...

Another thing i also suspected is the possibility of when you add just a test pipe or just an intake, you free up one side ofthe turbo. Therefore the other side has to work harder to keep up, if you catch my drift.

IMO this COULD produce some wierd noises. It wants to spool faster on the exhaust side but can't because of the restriction on the intake side...DARN guess I am going to have to buy a Corksport Intake and Turbo Inlet!!

 

[08_MS3_GT]

i'll try to give a listen later today to assess if the sound has been eliminated on my car - if so, then the sound is BPV-related.

there is a part of me that assumes it's just fluid dynamics (for engineers, air is a fluid too ). the boost peaks, tubes adjust to the pressure, etc. i've read that some weaker tubes can balloon under pressure, which could cause strange air noise.

F430TECH - regarding freeing up the turbo via exhaust or intake, i have an intake while you have a test pipe, so we've adjusted opposite sides. i don't really suspect that they're causing the same result. that being said, the mass flowrate of air through both sides can't change appreciably since the air feed goes through both sides of the turbo. yes, there's exhaust fumes added on the exhaust side, but that's going to be held constant by the ECU. removing a restriction in one location simply means that there will still be a bottleneck somewhere else.

back to fluid dynamics.. as i said, the other car i found this noise in was a first-gen Audi S4, which had either a T3 or T4. IIRC, the hot side of the K04 actually has a T25 fitting (?). is it possible that the whine upon full boost is related to the square turbo-to-exhaust connection? the wastegate dumping pressure into the exhaust could be the culprit. perhaps an ms3 with the corkspork downpipe, which isolates the wastegate to downstream of the initial turbo outlet, does not have the whine.

 

[F430TECH]

I too am an engineer 08_MS3 of the mechanical variety.

I agree with what you said but still wonder if by freeing up one side we are not putting a sideways strain on the impeller shaft. Simply because we are able to move air faster through one side than the other it kind of unbalances it. I don't necessarily disagree with the diagnosis on yoru part either, but mine began occuring after I had the BPV on for a little over a thousand miles...maybe I need to check the flange bolts, if they are loose it will be blue loctite time!!

Either way this is proving to be an interesting yet perplexing situation. I think when I fit my Corksport stuff I will be checking for shaft play just incase...

 

[spdjnke]

I too have experienced this, however after about two weeks of diagnosis and ALOT of trial and error, I found out the noise is caused by to much vacuum neg and positive boost pressure caused by the BOV's spring being to tight. Mine stop doing it after I adjusted my turbosmart spring tension to the lowest possible without causing stall, now it runs and sounds sooooo Sweet!! and almost no more strange noises, so give it a shot can't hurt.