I must say for a car in this price range there is a lot of road noise from the tyres. I have driven two other XK's before I bought mine and they were all about the same. Mine is a 2006 and the two I drove were 2007 and 2008.
Has anyone used noise reduction material in the car?
Do you have to strip the whole interiour out to get an effect or would it be enough to strip the luggage compartment and spare wheel and cover it and inner fender/arch with noise reduction material?

 

Noise. And to properly use sound deadening, the interior has to come out. Doing half the car is pointless because the other half is going to seem louder. Try different tires first.

 

Get some new tyres first.

 

Or wheel bearings.

 

This car has far more noise dampening than other cars. Just look at your wheel-well covering material.
My car is a proper luxury car on the highway.

You may have bad tires, bent wheel, bad wheel bearing.
Judging by the mickey mouse exhaust that was on there, my suspicion is that things were not properly replaced.

 

Um, not really. Cross between make it quiet and keep it light along with design limits. Rigid monocoque construction is going to transmit road noise into the cabin. There's a little rubber sprayed here and there on the bottom and they stuffed some foam pillows behind the interior panels around the rear quarters. Otherwise not much. My '68 Fairlane is much quieter. With the windows down at 60 mph I can hear crickets and birds chirping on the side of the road. It's surreal compared to the new stuff. My folks have a Rav 4 and it sounds like someone is whacking the roof with a rubber hammer when it goes over frost joints on a concrete road. Absolutely horrible thing to go long distance in.

 

Don't believe it's a wheel bearing, know how that sounds and a bent wheel I would feel some kind of vibration in the car.
Don't know what Queen and Country means with my Mickey Mouse exhaust and things not properly replaced. Just because it had a loud exhaust doesn't mean the car is bad maintenanced/repaired!?
The tires looks to be in good shape, they all wear straight but will check the age of them. Car has only done 38000km and they are maybe older then I think. :-)
Thanks so far!

 

Google tire date codes and see if they have the codes. Also see if they quiet down after a 30 ride at highway speeds.

 

Will do! :-)

 

The person who put this exhaust on a XK was the least bit concerned about highway noise or even preserving the sound dampening measures put in place by the factory. We can say that for a matter of fact and logic.
Now you have to wonder if they put all the braces back the clips back, the materials back on and took all the necessary precautions. In other words, if they were this reckless with the exhaust, what else were they careless about in the rest of the car. When they replaced the air filter, did they care about putting all the screws back.

 

Just replaced the OE Dunlops with Michelin PS 4s and the PS4s run much more quietly.

 

 

There's irony somewhere in this thread related to how many owners would buy a shiny exhaust regardless of looks or performance. Hard to judge a car by it's past.

 

There's something in this.

When I picked up my XKR it had 5 year old Michelin PSS on it that were well worn and rock hard, and the road noise was pretty much unbearable.

Put a set of brand new Michelin PS4's on it and it's so much quieter now...

 

Agreed tyres... I mean tires. Tire noise can masquerade as so many other noise related issues. Almost everytime I thinks its bearings or gear whine, it turns out to be tires.... And as Cambo pointed out above, it's not always the brand, but sometimes just the mileage, wear patterns and even age of the treads.

 

I'm interested in DynoMat deadening myself, and may look at it as a fun project for the rear wheel wells.

It's unfortunate for our lack of production numbers, but my old Lexus IS350 had undercarriage options you could order from Japan that were said to improve sound deadening by a lot.

 

Before one blindly forges ahead and plasters dynamat all over the interior body panels, they should first educate themselves on two items: First what are vibration dampening materials; and how do they perform their task?. Second, what is the difference between sound deadening, vibration dampening, and sound barriers? They are three distinct products with three separate functions.

While you're searching, school up on specialized heat shielding products and how they differ from sound mitigation products.

Dynamat is a vibration dampener and NOT meant to completely cover the interior. It's designed to add enough mass to a panel to cut down on the drum-like effect of that panel vibrating which can transmit and amplify the sound. But there are two other products you should to investigate before using a panel vibration dampener: Sound deadeners and barriers.

To quiet the interiors, specifically designed sound deadening, and sound absorbing, materials like poly fiber mats, and closed cell foam panels, (older cars used horsehair mats) do the job better and are much lighter than self adhesive butyl rubber stick on sheets. Most of the materials in our interiors are sound deadening fabrics and pads. So far the only panel vibration mat I seen is a 2x2 foot mat on the inside top of the coupe. I'm certain there's many more, but my point is that Jaguar did not completely line the inside of the sheet metal cabin with dampener material and neither should you or I.

Sound barriers are usually pretty thick and heavy and I found limited use for them on cars I wished quiet down.

Finally anyone who has plastered dynamat all over their bare interior sheetmetal [me for instance on another car] knows that on hot days in Florida, when the butyl wants to melt, they can bleed and what a mess that makes. So keep it away from exhaust and engine heat sourced areas like over mufflers or near turbo housings. There are much better heat and sound materials out there if you search. DII is great for heat shielding products, and there are lots of Dynamat clones which are much cheaper. gordo

 

I think it is because there is a difference between highway noise and exhaust sound

Similar to some one working on setting up an acoustically quiet room to play music in. Unwanted noise is gotten rid of to focus on the sound you enjoy.

 

I would first focus on tires/wheels/bushings.

A proper sports car is always going to have some noise.

Softer bushings die faster, but can help reduce noise. You may have dead bushings.

Not all tires are created equal, even within the same brand and model:

Person A with tire X switches to tire Y and posts they get less noise with the new tire.

Person B with tire Y switches to tire X and posts they get less noise the new tire.

Sometimes you just got a noisy tire.

Sometimes a better balance job can help.

My XK is a lot quieter ever since I went to new wheels. Its possible the old ones could be in need of straightening.

Several parts of the X150 are extruded shapes and not made from sheet panel. These are not going to see much benefit vibration dampers.

The most noise that I notice in my car is from the rear, the spare tire cover cuts a lot, but if you have it removed you'll find how much is getting generated by whats under neath. (A lot!)

Possibly some of the areas surrounding the rear trunk could use dampening as well.

Overall the vehicle is quite stiff, tires wheels and bushings will have the most effect.

 

Per the dynamat, use your knuckle to rap on the bodywork. You'll hear a hollow sound on the parts that will want to resonate at low frequencies. In my coupes case the worst spot was under the spare tire since it's directly effected by the muffler. I didn't have any matting so I wrapped an old dog blanket up and the tire holds it in place. made a huge difference in interior resonance. Also having the cheap little divider in place made a pretty big difference.