Exhaust drone noise

Exhaust drone noise

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Discussion

Aldhun

Original Poster:

179 posts

90 months

Thursday 5th September
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I have recently purchased a 2018 Vaquish S with very low milage from new. In vehicle settings; Sports mode had been set as the default.

In 30mph; 40mph; 50 mph; 60 mph speed limits on the motorways with lots of slowing down and speeding up in heavy trafiic, there is a constant drone from the exhaust which is very tiring.

Switching between Sports mode and Normal mode seems to make little difference. Could the exhaust valves be stuck in the open position? If so, is this an easy fix?

bogie

16,613 posts

279 months

Thursday 5th September
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Could be the valves are stuck, you should be able to tell quite easily though as there should be a step change in noise from 3500 to 4000 revs upwards. If little difference It could be the valves stuck.



Simpo Two

87,078 posts

272 months

Thursday 5th September
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Missing fuse?

LooneyTunes

7,584 posts

165 months

Friday 6th September
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They’re not the quietest exhausts, but as someone else has said there is a real step change in the noise levels at 3500-4000 rpm. When cruising or under moderate acceleration you’re likely to be above that point, at which it’s pretty intense, (I don’t think most people would describe it as a “drone”).

IIRC, the valves don’t open as freely in normal (sport mode off) driving and it takes a firmer, more prolonged, press of the accelerator to get them to do so.

Take it for a run in both sport and standard, give the accelerator a good stab, and see if the valves are opening/closing. Hopefully there’s something wrong and it isn’t the case that you just don’t like the exhaust note.

Btw, coupe or Volante? I find there’s more exhaust resonance especially in sport in the cabin of my Vantage coupe (dealer decatted) than the Vanquish Volante, even though the latter is probably actually louder externally, which usually results in me dropping the former in standard mode when cruising.

If it turns out that Sport mode is the problem, in the Vanquish there’s a menu option “sport hold” which remembers the last settings. Turn it off and it’ll default to standard.

DB9S Paul

136 posts

39 months

Friday 6th September
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I have a DB9 although it has had a secondary decat and has a Vanquish S rear box. I installed a switch to move between standard Auto Exhaust valve, permanently open and permanently closed.

I love the sound it makes when open, but it is loud and very droney when cruising at 50-60 as you describe.

I would buy a cheap Vacuum tester (example in link below) and get under the car, disconnect the vacuum line from each valve and test if they open and close, if not use some WD-40 or similar to loosen them off and when freed lubricate the valves with a copper based grease.

https://amzn.eu/d/gdQVA10

Calinours

1,328 posts

57 months

Friday 6th September
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Have you got underneath and checked the silencer box is OEM? Lots of people get tempted to mess with exhausts in pursuit of more noise or power - but there are often drawbacks and resonance (droning) at certain vehicle/engine speeds is certainly one.

I spent ages messing with everything from headers to back box on my V8S but ultimately discovered that the best compromise was exactly as the factory indended and in the end returned it all to standard.

On all VH cars you should be able to hear the vacuum pump at the rear running periodically with the car at idle, this holds the valves closed. If the pump, the pipes, or either of the actuator diaphragms fail the valves will remain open. A tell (of any failing components) is that the pump starts to operate more frequently at idle.

You should also be able to get underneath and see the actuator rods opening and closing the valves. Typically they are open on startup/idle, close after 5mins at idle or above 1000rpm then open again around 4000rpm, with sport mode maybe leaving the valves open at idle (but still typically closing them at 1000rpm), maybe opening them earlier or even just leaving them open at any rpm, model and year dependent.

Aldhun

Original Poster:

179 posts

90 months

Friday 6th September
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Thanks for the advice folks, I have booked the car in with Quantum Works next week. I will report back after they have had a good look at the car.

AstonV

1,617 posts

113 months

Saturday 7th September
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Maybe you have secondary cat delete. On the Vantage that makes a HUGE difference.

LooneyTunes

7,584 posts

165 months

Saturday 7th September
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AstonV said:
Maybe you have secondary cat delete. On the Vantage that makes a HUGE difference.
I am pretty sure they aren’t there in the first place on the Vanquish S.