Exhaust noise
#1
09-23-2017, 04:16 PM
Join Date: Jun 2017
Location: ann arbor, michigan
Age: 77
Posts: 34
Rep Power: 0 
Exhaust noise
I've always thought that my 2007 Bentley Continental GT has a louder exhaust note than it should.
Upon closer inspection, I discovered that the inner outlet of each muffler had a flapper valve. This valve was wide open. There appeared to be a vacuum actuator for each flapper. It further appeared that the actuator did not move the flapper whether the engine was running or not. Wiring the flappers closed reduced engine noise considerably.
I measured vacuum at the actuator, and it was about 5-7 in. Putting my vacuum pump on the actuator, and increasing the vacuum to 10-12 in made the actuator move and close the flapper.
I measured the vacuum at the hose that comes from the front of the car, and got only 5-6 in vacuum, engine idling.
I would have expected more vacuum at this hose. Is this normal for this engine?
Does it sound like there might be a leak somewhere along the line? The engine runs fine, no indicator lights.
Thanks for your help.
Bob
Upon closer inspection, I discovered that the inner outlet of each muffler had a flapper valve. This valve was wide open. There appeared to be a vacuum actuator for each flapper. It further appeared that the actuator did not move the flapper whether the engine was running or not. Wiring the flappers closed reduced engine noise considerably.
I measured vacuum at the actuator, and it was about 5-7 in. Putting my vacuum pump on the actuator, and increasing the vacuum to 10-12 in made the actuator move and close the flapper.
I measured the vacuum at the hose that comes from the front of the car, and got only 5-6 in vacuum, engine idling.
I would have expected more vacuum at this hose. Is this normal for this engine?
Does it sound like there might be a leak somewhere along the line? The engine runs fine, no indicator lights.
Thanks for your help.
Bob