Exhaust closes in sport mode - Maserati Ghibli Forum
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post #1 of 9 (permalink) Old 03-07-2017, 01:59 AM Thread Starter
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Exhaust closes in sport mode

So I noticed that in sport mode, the exhaust flaps stay open at idle, then close between 1k-3k rpm (unless it's a cold start, then they are open for first minute or so) and seem to fully open at 4k. Is there any way to keep the flaps open in sport throughout the entire rpm range or do you have to disconnect the vacuum lines, leaving them open in normal mode?
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post #2 of 9 (permalink) Old 03-08-2017, 04:03 PM
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yes, you need to disconnect the vacuum lines in order for them to remain open during the whole RPM range
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post #3 of 9 (permalink) Old 03-18-2017, 04:19 PM Thread Starter
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Originally Posted by paulserati View Post
yes, you need to disconnect the vacuum lines in order for them to remain open during the whole RPM range
Do you disconnect it from the muffler side or toward the engine? The one on the muffler seems hard to get to with your hands. Where is the other side located? Anybody have a picture?
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post #4 of 9 (permalink) Old 03-19-2017, 04:37 AM
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Do you disconnect it from the muffler side or toward the engine? The one on the muffler seems hard to get to with your hands. Where is the other side located? Anybody have a picture?
I disconnected on the muffler...just pulled up on the hose until it came off. I then put a vacuum hose cap on both the vacuum hose and the nipple on the muffler. it is pretty tight in there though. if you need more room, you can remove the black plastic "diffuser" portion of the rear bumper.
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post #5 of 9 (permalink) Old 04-13-2017, 06:35 PM
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Does anyone know the rationale behind the fact that the flaps close? Why don't they stay open permanently, since they aren't that loud to begin with?
Or, are there any downsides or negative results for plugging the vacuum tubes and therefor forcing the flaps to remain open at all times?
In the spirit of full disclosure I just this afternoon used another method of keeping the flaps open, that being wiring them open utilizing the small hole in the bracket and shaping the very stiff wire so as to prevent the vacuum from pulling the plunger that activates the flap mechanism. I'll observe the sound and engine performance for the next few days for any changes.

Last edited by ghiblihater; 04-14-2017 at 04:01 PM.
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post #6 of 9 (permalink) Old 04-14-2017, 04:05 PM
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Update of exhaust flap being wired open.
There was no noticeable change in the performance of the vehicle; there was, however, the presence of the same exhaust sound regardless of driving mode (sport, normal or ICE). Also the exhaust sound did not change with engine RPM. So, now the car's exhaust sounds like a gerbil farting all the time.
Why Mas. didn't engineer the thing to allow for selection of enhanced exhaust sounds at the touch of a switch is a mystery to me.
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post #7 of 9 (permalink) Old 04-16-2017, 07:33 PM
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Typically, exhaust flaps remain closed at low rpm to provide back pressure which allows the engine to make more low rpm torque.

2014 Ghibli SQ4
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post #8 of 9 (permalink) Old 04-19-2017, 08:51 AM Thread Starter
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Typically, exhaust flaps remain closed at low rpm to provide back pressure which allows the engine to make more low rpm torque.
On a turbo engine, you want the least restriction possible, no matter the rpm range. Only on N/A cars do you want backpressure, and even thats iffy. They probably closed the flaps at idle and up to 3k RPM for comfort/to reduce drone at cruising speeds.
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post #9 of 9 (permalink) Old 04-19-2017, 09:29 AM
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Legacy, I notice the drone you mentioned at what might be described as lugging conditions. I find that the drone can be nearly eliminated by a lighter touch on the accelerator, which probably also results in slightly improved fuel efficiency (not that that matters.) The drone can be quite resonant and may be irritating to some, but it nearly disappears once an even cruising speed is reached.
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