Unacceptable vibration/rattle @ 13,000 km SOLVED: loose exhaust hanger

[MightyMirageMpg]

I just have a hard time to believe the exhaust hangars have anything to do with harmonic vibrations unless your exhaust tips a tuning fork lol

Did it make Any change for you, ichobod?

[IchabodCrane]

I just have a hard time to believe the exhaust hangars have anything to do with harmonic vibrations unless your exhaust tips a tuning fork lol

Did it make Any change for you, ichobod?

You may be missing the point here.. no one has said the hangars are an issue. What has been said is that the deletion of the flex joint and unified cat/header could make the connection between exhaust and engine too rigid, allowing engine vibration/resonance to travel full length of the car.
..and first drive since adjustment seems to be worse but I'll try again tomorrow.

[MightyMirageMpg]

Theres really no flex joint or spring bolt coupler in the entire 2017 exhaust? I thought this was de-bunked?

If this was the issue (too tight exhaust), there would be hundreds of complaints about this, as ever 17 would have the issue. Or don't you think it's an isolated issue do to a faulty part specific to your exhaust?

With so much going on with the exhaust (wind hitting it, road bumps moving it around, each little puff of exhaust rattling it, and the engine moving it front to back) i find it difficult to believe its causing a "specific RPM based vibration" at anything other than parked

[IchabodCrane]

Theres really no flex joint or spring bolt coupler in the entire 2017 exhaust? I thought this was de-bunked?

If this was the issue (too tight exhaust), there would be hundreds of complaints about this, as ever 17 would have the issue. Or don't you think it's an isolated issue do to a faulty part specific to your exhaust?

With so much going on with the exhaust (wind hitting it, road bumps moving it around, each little puff of exhaust rattling it, and the engine moving it front to back) i find it difficult to believe its causing a "specific RPM based vibration" at anything other than parked

You're right.. there is one spring bolt coupler in the system still. but in a new car every inch of the exhaust from here back is one welded piece. the spring bolt coupler is fine for allowing the tail pipe to rock about in an orbital fashion but without the flex pipe engine vibrations are simply transferred down the entire length of the car. The resonance is causing a secondary vibration/buzz in another component of the car, heat shield, body panel, poorly routed hose or wire...?
This vibration/buzz becomes noticeable at specific rpm under certain load conditions because that's where the cvt holds rpm. it may be just a split second buzz as rpm zips on by in a standard equipped car but as the cvt cruises at much lower rpm and tends to lug a bit before shifting, the issue is more pronounced.
The problem seems most prevalent in the GT trim cvt with 15" wheels.
It may well be that our focus on the exhaust is erroneous as there are other factors in play.

[Fummins]

You're right.. there is one spring bolt coupler in the system still. but in a new car every inch of the exhaust from here back is one welded piece. the spring bolt coupler is fine for allowing the tail pipe to rock about in an orbital fashion but without the flex pipe engine vibrations are simply transferred down the entire length of the car. The resonance is causing a secondary vibration/buzz in another component of the car, heat shield, body panel, poorly routed hose or wire...?
This vibration/buzz becomes noticeable at specific rpm under certain load conditions because that's where the cvt holds rpm. it may be just a split second buzz as rpm zips on by in a standard equipped car but as the cvt cruises at much lower rpm and tends to lug a bit before shifting, the issue is more pronounced.
The problem seems most prevalent in the GT trim cvt with 15" wheels.
It may well be that our focus on the exhaust is erroneous as there are other factors in play.

That doesn't make sense to me how wheels could have an effect on an rpm based vibration? Do you think all cars have this noise and it's just more noticeable on yours? Just a thought, I noticed the air cleaner resonator(silencer) shakes around a lot and can make a noise at idle on a few higher mileage cars, maybe this could be whats rattling around on yours?

[MightyMirageMpg]

Ichobod, in your initial post you said it occurs between 17-2100rpm (or something like that) does it come back at 34-4200rpm? Does it happen EVERY single time?

[IchabodCrane]

It occurs twice... at around 1700 rpm and again around 2100 rpm. this is at 70-80km/hr and 110km/h respectively.
Doesn't happen at higher rpm as far as I know.
The resonance happens every time but the vibration/buzz lessens or disappears the warmer outside temp gets.
Put another 110km on it today since "adjustment" and it's back to pre-adjust annoyance levels.

[Mitz]

It occurs twice... at around 1700 rpm and again around 2100 rpm. this is at 70-80km/hr and 110km/h respectively.
Doesn't happen at higher rpm as far as I know.
The resonance happens every time but the vibration/buzz lessens or disappears the warmer outside temp gets.
Put another 110km on it today since "adjustment" and it's back to pre-adjust annoyance levels.

Do you have some sound clips to share so we can hear it too?

I'm inclined to suspect the rattling is coming from the muffler. I've experienced this selective rattling before which occurs at somewhere between 900 to 1000 RPM and in the range near 3000 RPM. I did not have the opportunity to rip up the muffler as I left it at the shop where I had the muffler replaced. When the muffler is shaken, you can hear something's detached inside that moves causing the rattle.

[IchabodCrane]

I've heard about that from others but if I go under the car and knock the exhaust about with the heel of my hand it doesn't make any noise.

[Mitz]

I did the same before. I had a healthy discussion with the mechanic at the muffler shop and arranged to replace what's necessary to remove the cause of that irksome rattle.

I didn't think it was the muffler until it was removed. When it was removed, I can't believe what I did hear when I shaked it!