I have noted some references to some sort of active directing of engine noise to the interior. Anyone know how they do it? I ask because when I get into throttle aggressively there is a distinct volume and tone change beyond that associated with higher RPM. It sounds like a damper of some sort is maybe opening because the growl becomes distinctly and sharply louder. Is it just induction noise or is there more going on?

 

There is an acoustic channel piping engine noise into the interior. This is a "feature" for some people. Supercharged engines can have subdued intake noises, but these are often swamped by the supercharger whine. Jaguar uses a fairly quiet supercharger design.

 

So far i have driven 07 S type R, 2011 XF with the NA 5.0 liter engine and 09 XF supercharged.

I have to say the 5 liter engine sounds the best.

 

Jagular, its not the SC thats quieter. Its the air intake piping and filter boxes. go to open elements like a K&N cone without the boxes and theyll scream just like any other

 

I am comparing the civilized quiet of the Jaguar with the insane whine of say the Ford lightning pickup which uses essentially similar technology.

 

It seems like an abrupt transition. Is there a servo controlled door or something that opens? What are the mechanics of it?

 

You also have to remeber that the XF SC has a double bulkhead between the engine bay and the interior to keep the noises down.

Jimm

 

I sir, tend to disagree...

Jaguar XFR | High Speed Test - YouTube

 

I drove a 2010 5.0L NA for 20,000 miles . Now I have 5,000 miles on my 2011 5.0L S/C. I must say the NA sounded much-much better/sportier/snortier under acceleration. The S/C is very subdued, which actually detracts from the feeling of speed. Outside the car, the S/C exhaust sounds great, but you can not hear it inside. I wonder if the XFR is different than the S/C in this aspect?

 

Superchargers alter intake noise. Supercharger designers spend a lot of engineering time trying to improve efficiency nd reduce noise. Airflow noise can be evidence of flow inefficiency.

As for exhaust noise, Europeans regulate this very tightly. European cars are quieter than North American regulations require.

It is puzzling to me why anyone would want to drive a noisy street car.

 

Jagular,
You are missing my point. It's not the db level of sound, but the quality of the sound. Nobody says the NA is more or less noisier than the SC. It only sounds better, and on this point there seems to be no argument here. The SC is more of a sport-sedan than the NA, so definitely is missing on this aspect of the driving experience.

 

I get the point. I don't understand the point. Car manufacturers go to great lengths to make the car quiet , including intake, combustion and exhaust noise. From inside the car it is desirable and less fatiguing if noise is reduced as much as possible. Brrm brrrm noises are for kids playing with toy cars.

 

^
Not true at all!

On the contrary, you don't think if Jaguar wanted they could have made the XF's quiter.... Of course they could!

I can name quite few manufacturers that go to "great lengths" to actually give their cars a very exotic exhaust note or that baritone intake growl.

And, if you think cars that make brrr brrr noises are for kids, i am sure you would be delighted to drive a electric Prius.

 

Tell me that the sound of the XFR in that vid didn't make you smile....

 

My ride is a 2011 XF Premium with the NA engine and I love the throaty sound under acceleration, however an associate in the office recently got a 2011 XF Supercharged as a loaner (275 miles) and there is a noticeable lack of the same throaty sound under acceleration. Both are extremely quiet yet the SC lacks the muscular sound of the NA.

 

I have had more comments on how good my car sounds on the outside than any other vehicle I have owned (including an AC Cobra with a 350 Windsor with straight pipes). They have done beautiful things with the exhaust tuning of the SC. My question was more about the abrupt transition from quite quiet to growl with aggressive throttle application.

 

"Tell me that the sound of the XFR in that vid didn't make you smile...."

Yes, but this is what you hear outside the car - mostly exhaust. From the inside, it is not very exciting, definitely not as nice as the NA under acceleration. At least it is with my SC.
Maybe the XFR is better in this regard than the SC? but I doubt it.