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How ever having said what I said in post #14 the pics look odd as there appears a valve in each pipe .
Inner is open , outer closed , which is normal if the engine is off .
So for the “ sport “ / loud sound to seemingly be there all the time there must be a fault that opens the outer ( and the inner in this case ) all the time .
So no vacuum or insufficient vacuum is eaching the outer valve to suck it close and it’s prematurely opening = loud noise .......This needs investigating.
On warm idle the flap is closed, and the other pipe looks "closed" just like when the engine is off so I am not sure if this is fixed like that or not.
Basically I really need the car to be quieter on normal mode
Ah, OK - so there is not a dedicated switch to open/close them. But switching to Sport Mode - i'e' setting the suspension to sport height = opens them?
Originally Posted by John Fiammetta
Vacuum .
They are spring loaded open Vac closes them .
All quad pipe high end set up the outside pair of the quad is vacuum valved . It’s a generic exhaust system not Bentley specific .
Ferrari , Maserati , Aston , Alfa , M series BMW , Merc AMG etc etc .Bentleys quad are disguised by the oval tail pipe trim .
To permanently keep the outer pair open + associated noise if you wish , you pull off the Vac pipe and block it off .....self taper or golf T .This fools the engine management and no CEL s .
So when you initially start when cold , it’s open hence the growl until there’s sufficient Vac to pull it shut .
Sport mode or hard acceleration cuts the Vac .....it springs open = the noise .
Ah, OK - so there is not a dedicated switch to open/close them. But switching to Sport Mode - i'e' setting the suspension to sport height = opens them?
Yes as said it’s most likely to be a solinoid somewhere controlling the Vac .Hence investigation is needed ,
It was my bad saying "one is close, one is open". There is only one flap on each side of the car.
At warm idle, the flap is close. It opens when the engine is off. I haven't had chance to see its position on acceleration.
So what do you think the reason causing loud pipe sound on normal mode? Or it is designed like that?
How is everyone car sound on normal driving mode?
Can you get some pictures of the underside of the vehicle showing the complete exhaust system, is it possible that a previous owner removed some other parts, ie secondary cars, resonators, ect.
Can you get some pictures of the underside of the vehicle showing the complete exhaust system, is it possible that a previous owner removed some other parts, ie secondary cars, resonators, ect.
Thanks for your help. I will take detail photo of the exhaust system and post here soon
I don't believe the suspension setting has anything to do with the exhaust flaps. When you put the gear lever into S (one notch past D), that opens up the valves. You are correct that there isn't a dedicated switch to open the valves like most other cars have. With mine, sitting at a stop light in D sounds quiet, when I pull the lever back in to S it gets louder.
I don't believe the suspension setting has anything to do with the exhaust flaps. When you put the gear lever into S (one notch past D), that opens up the valves. You are correct that there isn't a dedicated switch to open the valves like most other cars have. With mine, sitting at a stop light in D sounds quiet, when I pull the lever back in to S it gets louder.
I really love that, in D it's quiet and sounds loud on S mode. Mine are loud on both 😥😥😥
I don't believe the suspension setting has anything to do with the exhaust flaps. When you put the gear lever into S (one notch past D), that opens up the valves. You are correct that there isn't a dedicated switch to open the valves like most other cars have. With mine, sitting at a stop light in D sounds quiet, when I pull the lever back in to S it gets louder.
Can you get some pictures of the underside of the vehicle showing the complete exhaust system, is it possible that a previous owner removed some other parts, ie secondary cars, resonators, ect.
Hi Johnny,
Hope you are doing fine and safe.
Today I had a chance to take photos of the exhaust system, please check below photos. I see that the drone sound is very loud at low RPM ~ 1000 to 1500 rpm, when the speed at ~ 20 - 30 km/h. It's quite annoying at low speed.
Hello @TungNguyen ,
It would be interesting to see the under side of your friend's "Speed" version exhaust, as I would think the pictures you post of your vehicle to be the Speed exhaust system, as it is missing the mufflers after the secondary cats, or if someone else here can share a photo of their Flying Spur exhaust setup to compare, but we would need both the Speed and non Speed to see the difference, my GT came with the mufflers after the secondary cats, but no "H" pipe as yours has.
Is it possible that someone gutted your secondary cats for more free flow or sound, your setup does not at all look like someone cut out the mufflers, as the are no welds visible, or did someone swap out the center section for the non muffler setup ?
This is interesting, according to Scuderia's website the FS has two setups, but its one or the other, not both combined like my GT setup, #20 with the secondary cats only is for North America and Japan, whereas the #12 with the mufflers only and no secondary cats is for the rest of the world.
And just for comparison and knowledge of the GT setup, straight pipes (no secondary cats no center mufflers) for the ROW, secondary cats only for NA and Japan, and then the secondary cats and mufflers for looks to be only NA.
Johnny
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Last edited by Johnny Hotspur GT; May 14, 2020 at 10:43 AM.
