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      03-13-2019, 10:41 AM   #1
LOW4LYF
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Question CG Precision Variable Sound Controller (VSC-2) Questions

Question. Does it hurts having the flaps most time in closed position? Just moved in a gated community and cutting my commute time, so don’t really need that much sound specially in the morning. Means I would like to drive with closed flaps.
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      03-13-2019, 11:02 AM   #2
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absolutely not.
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      03-13-2019, 11:30 AM   #3
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If you're just in the housing community and not driving at high rpms it wont hurt anything
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      03-13-2019, 11:32 AM   #4
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Definitely no harm. Dont even need a valve controller for this, just keep it in efficient setting where the valves are closed except heavy throttle and high rpm applications.
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      03-13-2019, 12:19 PM   #5
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Okay, thanks!
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      03-13-2019, 06:17 PM   #6
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In other cars you would see a difference in blackening of the tailpipes depending on the position of the flaps but not with the design in this car according to BMW. I drive with my flaps open constantly and I need to clean the two outer tailpipes more. If you keep them constantly closed you will notice the same for the two inner tailpipes.

In theory: with the flaps closed you might loose very little power at high RPM because of the increased backpressure. With the flaps open you might loose a little bit of power at low RPM because of the decreased backpressure. This has to do with the valve overlap. We are probably talking about 1 kW of power and 1 Nm of torque in difference.

In practice: in all honestly you will not notice and I doubt that this is measurable thanks to the turbos and the catalytic converters. The flaps are there primarily for the exhaust note and at low RPM they remain closed to prevent drone as well.

I keep them open and I never shift to below 2000 RPM because of the exhaust drone in the range of 1300 RPM to 2000 RPM. Instead of keeping them closed constantly you could stick to the OEM mode and have the DME activate them. Like gatorfast mentioned in Efficient mode they remain closed.

Last edited by G4BR13L; 03-13-2019 at 06:49 PM..
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      03-14-2019, 09:40 PM   #7
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Quote:
Originally Posted by LOW4LYF View Post
Question. Does it hurts having the flaps most time in closed position? Just moved in a gated community and cutting my commute time, so don’t really need that much sound specially in the morning. Means I would like to drive with closed flaps.
Let me know if you decide to get this part
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      03-14-2019, 10:27 PM   #8
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Quote:
Originally Posted by mike@x-ph.com View Post
Let me know if you decide to get this part
I’ll let you know when I’m ready Mike. I don’t think my BMS can flap will work with Electronic Steering Wheel
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      03-15-2019, 12:19 AM   #9
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I love mine!
The integration with homelink sealed the deal for me!
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      03-15-2019, 10:41 AM   #10
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Quote:
Originally Posted by aBMWfan View Post
I’ll let you know when I’m ready Mike. I don’t think my BMS can flap will work with Electronic Steering Wheel
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      03-18-2019, 10:05 AM   #11
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Quote:
Originally Posted by Railgun View Post
Not in a turbo'd car. Backpressure is the enemy in all cases. While exhaust scavenging is important, it's not as important as a N/A car manifold/rest of exhaust design.
That's why I added:

"In practice: in all honestly you will not notice and I doubt that this is measurable thanks to the turbos and the catalytic converters. The flaps are there primarily for the exhaust note and at low RPM they remain closed to prevent drone as well."
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