I did a search , didn't find a thread with this issue. The car sat garaged for 8 years. Noticed a lot of engine noise / vibrations coming through at idle and a noise that sounds like induction noise that is between 1600-200 rpm only and under load that is most noticeable in top gear is actually present in all gears if under accel / load. Replaced engine mounts, sub-frame mounts, control arm bushings. (everything made of rubber I could find) - The only remaining noise if the droning at 1600-2000 under load. (sounds like the air box is loose but it's not) Anyone have any input on this?

TY - Brendan Sexton

 

How many miles? What kind of shape is the air filter in? Is the bellows on the air intake ok??

 

120k - Air filter is new. Intake all looks good. The noise doesn't get louder if I accelerate harder like an intake should, but it sounds just like that. It's a 2000 XJ8 VDP

 

On the 90* turn at the firewall, is the silencer tube on the intake there?

 

I have no clue on the cause and it is not my intent to divert Jaaag00xj8's thread by my lack of knowledge ... but out of curiosity, Jaaag00xj8, does this noise disappear if you engage the transmission "sport mode" button while in that speed range? Does it disappear briefly if you back off the throttle between 50-60, or downshift to 4th? I have no idea the reason, but my '03 VDP has a noise I'd call a low frequency hum at that speed/rpm range. It goes silent or mostly silent if "sport" mode is turned on with the mentioned actions. A few VDP owners I have spoken to over the years have heard the same on their cars and some suspect a harmonic vibration. But I can't figure out if it's a harmonic why it might go quiet(er) engaging sport mode because at that point either way you are in 5th, the TC is allegedly locked up and the RPM input and output is the same.

Again, I don't want to take this off topic. I am not awash in technical knowledge or experience. This just sounds similar to an unsolved mystery on my car.

 

Standard exhaust?

I ask as the stainless one I got made drones around those speeds & goes quiet again when moving faster. It's most vexing.

 

8 cylinder engine has exhaus pulse resonate rpm around 1800rpm. So it drones exactly where Jaag00Xj8 described.

 

factory exhaust. I didn't notice this issue before it was stored so I'm thinking something rubber...? Might just be the pulses like Vauxi said..?

 

Yours is a torque converter clutch noise (shudder), most probable cause is valve body wear and it gonna have to be rebuild either by you or someone else

 

Isn't the humming noise/ compressor like the fuel pump?

 

It is fairly loud and comes from the back of the car. I'm thinking the resonance may be exhaust as the exhaust sounds seems a bit louder than 10 years ago. Going to sport stops the noise without the rpm changing at all. (Converter clutch remains engaged from what I can tell as rpm remains steady and it takes about 2 sec for the noise to stop.) - The noise is a droning / hum , low pitched. No vibrations felt. I have replaced every suspension bushing in the suspension and subframes (not due to the noise , just to freshen up the ride and make it as quiet as new.)
I run a repair shop , my next step is to use a chassis ear to listen to the individual components for a solid diagnosis. I'll update when I get that done.

Still wondering is any one with the standard wheel base has has the same issue....

 

Update: My microphone 'chassis ears' (not that brand) has arrived. It has 6 channels to listen to at the same time. (switch between mics) I'm going to put one on each tailpipe , one on the rear differential , one on the center prop shaft support , one on the transmission output housing. My current working theory is a driveline resonation, I may need a new flex joint. (the only rubber bit I have not replaced as part of the restoration. Since we have not heard from any standard wheel base owners on this noise the issue must lie in the differences in the prop shaft or exhaust. Since 'sport' stops the issue (I'm assuming it unlocks the converter thus smoothing the impulses from the engine firing every 45 degrees of rotation. I'm off to France for 2 weeks so the next update may be a month away.

 

Have fun, and keep us posted upon your return.