Looking for help - annoying metallic whine at 2000 RPM

[trojannemo]

I posted this on the Facebook S550 group, and got very little traction. Some suggested that "it's normal" but I've never heard it on any other S550 i've ridden or owned. Even if it's really "normal" - it's also "annoying" and I would like to find a solution. Let me know if you have any ideas please. Message below is what I posted on Facebook.

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I know there are some knowledgeable people in here, hopefully one of you can help me out.

2017 GT, convertible, auto. Installed Solo Performance Mach Thunder 3" catback exhaust and JLT intake at the same time. Initially nothing wrong, then I started to notice a high pitched sound like if my brake pads were bad, but coming from the intake area. Here are my observations:

- only happens when on the move, not if I'm parked and revving
- happens between 2,000 RPM and about 2,800 RPM
- happens whether i'm driving slow or breaking the speed limit. if I start to gently push on the accelerator and i'm between 2K-2.8K RPM without pushing the whole way, it happens, consistently, with no fail, regardless of current speed
- if I floor it or push the accelerator more than gently, it's either gone or drowned by the engine noise
- if it's making the noise and I let go of the accelerator the sound immediately stops
- there is absolutely no chance it is from my brake pads or rotors, since it never happens while braking - but it sounds just like metal on metal brake pads...

Since I noticed this sound we replaced the throttle body, which was going bad. Added mak cat delete. Did sound tube delete. Rotated the intake filter. Removed the intake filter for a short test drive.

- no change at all in the behavior. I was hoping that removing the filter would make it go away, and then it's just a defective filter...but nope, same noise.

I have no engine codes or errors. No other apparent issues.
But the sound is irritating and a little embarrassing considering it sounds like something is obviously wrong with the car.

When taking off the intake filter I noticed water collected at the bottom of the intake housing or plastic, whatever it's called. The lip of the intake where the filter attaches was moist. I don't know if this is normal, I thought it was, but figured I would mention it now just in case.

Here's a video clip. Best times to hear it is at 0:50, but it can be heard a few times throughout. Adobe Audition says the noise is between 16kHz and 19.5Khz.



Any ideas what to look into?

Thank you.

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[ChiTownStang26]

Kind of hard to hear the sound cause of the wind but I do hear it.

First I'd put the stock airbox on since you can do that quick then see if it's still happening.

Second I'd make sure all the bolts/hangers are right and tight on the catback (I'm thinking the exhaust could be rubbing)

Third and what I really think it is, is a defective muffler. Had that happen on my old v6 with the roush AB and that's the almost exact noise it made. See if you can make that noise by throwing revs at it while parked (easier if you do it in a garage so the sound bounces off)

Lastly if your catback isn't welded unbolt it and throw the stock on and see if it's still there.

If you eliminate everything you've done to the car then it's safe to say it's a new unrelated issue. Hope this helps.

 

[trojannemo]

Thanks for the response. I'll respond to each thing below.

Kind of hard to hear the sound cause of the wind but I do hear it.

First I'd put the stock airbox on since you can do that quick then see if it's still happening. - NO LONGER HAVE IT :-(

Second I'd make sure all the bolts/hangers are right and tight on the catback (I'm thinking the exhaust could be rubbing) - WILL CHECK

Third and what I really think it is, is a defective muffler. Had that happen on my old v6 with the roush AB and that's the almost exact noise it made. See if you can make that noise by throwing revs at it while parked (easier if you do it in a garage so the sound bounces off) - DOESN'T MAKE THE NOISE WHILE PARKED. NO MUFFLERS THOUGH, THIS EXHAUST USES HELMHOLTZ RESONATORS

Lastly if your catback isn't welded unbolt it and throw the stock on and see if it's still there. - DON'T HAVE THE OEM EXHAUST :-(

If you eliminate everything you've done to the car then it's safe to say it's a new unrelated issue. Hope this helps.

 

[ChiTownStang26]

Well that puts us in a difficult diagnostic challenge...

Is the catback welded? You can always drive it around the block without the catback, it'll sound like shit but you'll be able to hear the sound still if it's not the exhaust. Idk why but my money's on a defective part in the exhaust, even a bad weld can do it. Had a shitty welded hpipe that was leaky and sounded like a diesel truck.

 

[trojannemo]

My understanding is that it is not welded but bolted on. I have no way to remove it myself, but I'll make an appointment with the shop and see if they can check some of the things you're recommending. I am a bit surprised that you think it's from the catback since the sound is most definitely coming from the engine bay.

 

[ChiTownStang26]

Lol I'm not that mechanically inclined when it comes to diagnosing engine sounds. Metal on metal coming from the engine is never a good sign, I'd be gentle on her till this is resolved.

 

[Zelek]

Check the intake itself. Keep things simple with what you changed. Metal on metal from a catback is usually due to a loose clamp. This doesn't sound like that. This sounds like something with the JLT intake if you ask me. If you swap back to your regular stock intake, does it still do the noise? Easiest way to rule it out. You could also check the intake and make sure everything is secure and tight, nothing loose.

 

[Fordever]

2017 GT, convertible, auto. Installed Solo Performance Mach Thunder 3" catback exhaust and JLT intake at the same time. Initially nothing wrong, then I started to notice a high pitched sound like if my brake pads were bad, but coming from the intake area.

Wha'ts the time frame from mods to first noticing this sound?

 

[trojannemo]

I don't know really, i would say a couple to a few weeks?

 

[Fordever]

I don't know really, i would say a couple to a few weeks?

So if you have a clamp issue, as others have suggested, this time frame would be about right.

I know I am not really helping with that answer, but the more info given on the issue, the better and may give others some different ideas.

I am still thinking......

 

[Bluelightning]

The whine/whistle that you hear sounds like air getting sucked through the high volume conical air filter. Sounds like it changes or goes away depending on how far your TB is open and how much air it is sucking in.

 

[trojannemo]

Yes, that is how it all sounds. But when I removed the air filter altogether and drove around the block, the sound was still there. So it's something other than the air filter itself causing the whine.

 

[Fordever]

Did you ever figure out where the whining was coming from???

 

[trojannemo]

Yes. The JLT intake tube. My preferred shop changed me out for a used Airaid closed box and it mostly went away. They all at the shop insist it is a normal sound of intakes and most people like it. I put the JLT back on since it's painted and is newer (and performs better than the no tune required Airaid they had on hand).

JLT is apparently offended that I've "sullied" their name with my concerns. They insist that the sound I'm hearing is either 1) normal or 2) doesn't exist because they can't hear it in the videos I've recorded.


I'm learning to live with the sound. Still annoys me but what can I do.

 

[Fordever]

Yes. The JLT intake tube. My preferred shop changed me out for a used Airaid closed box and it mostly went away. They all at the shop insist it is a normal sound of intakes and most people like it. I put the JLT back on since it's painted and is newer (and performs better than the no tune required Airaid they had on hand).

JLT is apparently offended that I've "sullied" their name with my concerns. They insist that the sound I'm hearing is either 1) normal or 2) doesn't exist because they can't hear it in the videos I've recorded.


I'm learning to live with the sound. Still annoys me but what can I do.

Glad to hear you figured it out. Sorry you have to live with the sound.

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