Between about 45mph and 60mph, if I take my foot off the gas I can hear a slight low pitch whistle that lowers in pitch as speed decreases. If i put my foot back on the gas even a little (so not coasting) then it goes away. Foot off - comes back. Only audible in that speed range. It's louder at beginning of drive, and softer (but still there) after say 20 mins of driving. Happens in any gear. I have exhaust on quiet mode when testing this, obviously. Anyone else experience this? 15 R, 18,000k miles. I've owned it since 16,200 and it has done that since I got it. I'm a few months away from end of factory warranty.

 

Never noticed that on mine, and I'm pretty good at noticing strange noises.

 

It could be supercharger whine/whistle.
Even on a stock untuned F-Type, both V6 and V8, some can hear a fairly faint supercharger whine at small throttle openings, I know I could before I put the VAP pulley & tune on. Then as soon as I opened the throttle a little more it either disappeared or was wiped out by the exhaust noise.

 

That's what I thought too, but then there is this from the XKR forum https://www.jaguarforums.com/forum/x...hine-c-165711/

 

I would say it's not supercharger whine.

Like I said: proportional to vehicle speed. doesn't matter what gear I'm in (thus not related to engine speed). happens only when my foot is off the gas. I was thinking something in the rearend?

 

Got the same sound at the same speed on my car . It comes from the rear diff when
the bevel gear tooth flank change their contact surface from load to push side.
Only can hear it with the roof closed . Started at about 10'km and remains the same
until now (30'km). Changed the diff oil at 20'km to see if there is a lot of wear debris
but there wasn't much although the oil was pretty dark. No change in sound level after the oil change . Hopefully the diff remains calm during acceleration and keeps its sound level on deceleration for a long time. Fingers crossed.


Regards
Ulrich

 

Doppler Effect - the change in pitch of the 'wows' from the admirers as you glide past. Once you put your foot on the throttle, the exhaust note drowns them out. Over 60 mph, you can no longer hear them.

Perfect scientific logic but there could just conceivably be an alternative mechanical explanation.

Graham

 

Exactly my thoughts, and we have the same symptom as you describe it. I think I will not worry about this, but I will mention it when I bring it in for oil change.