FF exhaust drone in stop/start traffic

Today was my first longish trip in my recently acquired 2014 FF. Unfortunately it took 3.5 hrs to do a 2hr journey due to heavy traffic.

The car is a joy to drive on the move, but by the time I reached my destination I just couldn't wait to get out of it.

When sat in traffic the car idles at a level which is tolerable. I have a non HELE car. However at between 1200 & 1500 rpm just as you're creeping forward there is a frequency drone that goes right through me to the core. I had a splitting headache and was absolutely drained from it once I reached my destination.

Unfortunately in heavy traffic you hit this spot almost constantly. The moment you're through 1500rpm and driving/accelerating, it's gone.

Anyone else experienced this?

The car is standard.

I've ordered some Dynamat and will line the boot floor to see if that helps.

It's not loud as such, it's just a specific frequency drone at low revs.

 

Sorry to hear, I've definitely never experienced this. It might be worth checking that your exhaust valves are still plugged in and operational. I have a novitec but even still, with vales closed its nice and quiet.

 

Lift up the car with engine running and look for an exhaust leak before Dynamat. Like suggested above, check the valves too. Make sure the valve isn't seized.

 

Just done a long journey in our 2011 FF.
I was listening out for drone in any traffic we encountered and there was nothing.

The only intrusive sound I could hear at low RPM was transmission whine in 1st and 2nd gear. That’s it.

 

Stock exhaust? My FF was droning at stop lights because it was low on coolant and the valves opened up to prevent overheating I guess. Check your coolant level, once I got mine refilled the drone went away.

 

Ok so I've done 1000 miles over the last couple of weeks and I've tied the drone down to a very specific rev range.

At 1300-1500rpm there is a resonance that making the shell of the car vibrate, the moment you go over that the valves open and it all stops. So the resonance appears to be in a tiny window just before the valves open. Would 1500 rpm be about the right range for the valves to open or should it be somewhere else?

I've found driving in sport/bumpy road keeps me out of this rev range so I'm currently driving around the problem, quite successfully. I really need to sit in another standard car and see if this is a car issue or an issue with me as noises and sounds can be very personal.

I find there's a lot of ambient road noise, tyre roar in particular, this may be amplified by the awful concrete surfaces of British Roads. Yesterday though I was cruising at 70-80mph and the road noise was almost drowning out the sat nav instructions it was that loud. Car is running new PS4S's

 

The car had a major service two weeks ago and all is well mechanically.

I'm now starting to wonder if a previous owner has somehow tinkered with the standard exhaust.

 

Loud is the wrong word for the problem I'm getting. It's not loud as in noisy, it's a very low frequency resonance that seems to be completely in tune with the bodyshell of the car in a small rev band. The moment you squeeze the throttle everything seems to breath freely and the resonance is eliminated.

Rather than stab in the dark I think my first action is to find a simlar standard car and see if I find it occuring on another vehicle.

 

Exhaust valves open much further up the rev range than 1500rpm. The revs at which they open depend on manettino setting and throttle opening.

It’s possible that a previous owner had pinned the valves open by disconnecting the vacuum lines and plugging them. A simple way to check would be a static rev of a warm engine. if it’s muted, the valves are closed. If it roars then the valves are open. Check out the Novitec FF video to see the difference in sound between valves opened and closed.

 

I think I need to get someone who knows what they're looking at to just check my car over.

This is pointing towards some sort of modifcation, the car roars.

 

Could you please verify that the hydraulic lines from the PTU pump is not touching the body. The PTU pump is located on left side just in front of left front wheel arch. I know this is a possible thing since I had it on my car. The solution is simple, just make the hydraulic line not vibrating. And yes it might very well be in 1300-1500 band. It could also be triggered by enabling the engine brake, say you are using cruise control, and disengage, then the same vibrating sound might be noticed also.

 

Image Unavailable, Please Login

It should be one of the hydraulic lines in the picture above that goes between the PTU (center part) and pump (right side on the picture). One of them can sometimes brake loose and then starts vibrating against the surrounding parts and well I could easily see someone take that for droning.

 

So to update this thread. We've found a solution.

I haven't stopped the "Drone" (which of course could be a very personal frequency thing) but we have stopped the vibration and discomfort, in the process making the car a lot more comfortable at lower revs.

We fitted Dynamat to the boot, fuel tank and rear seat area. What we did notice when doing so is this car had obviously had a stereo install that had been removed and not much thought had been put into reassembly, so there were vibrating fittings which have been all dealt with.

What the Dynamat did was remove the "drumming" vibration from the cars bodyshell by quite a degree.

Oh and if anyone knows what the blue plug is for on the right hand side of the boot we're all ears.

Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Image Unavailable, Please Login

 

Wow, you did a great job on that! I’m sure it will make quite the difference.

 

The difference is huge. I've driven the car into central London a couple of times and sitting in traffic is actually now quite normal.

I have no doubt some of the noise I was initially struggling with was due to lazy reassembly by a previous owner/workshop.

However adding dynamat has reduced this further and made the FF a comfortable place to sit in stop start traffic. It has actually reduced the drone to a level that its simply not noticeable.

This is a genuinely inexpensive mod that improves the interior comfort of the car enormously.