S8 D3 'Flapper mod'
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S8 D3 'Flapper mod'
Hi all,
I've been researching doing the exhaust 'flapper mod' to my S8, for the uninitiated this basically means forcing (or tricking) the two flaps in either muffler to stay open all the time. From what I've read all I (should) need to do is block the vacuum pipe which feeds the piston valve on each of the mufflers, I'm thinking of doing this with a small clamp. Has anyone else successfully achieved this on an S8?
Thanks in advance!
I've been researching doing the exhaust 'flapper mod' to my S8, for the uninitiated this basically means forcing (or tricking) the two flaps in either muffler to stay open all the time. From what I've read all I (should) need to do is block the vacuum pipe which feeds the piston valve on each of the mufflers, I'm thinking of doing this with a small clamp. Has anyone else successfully achieved this on an S8?
Thanks in advance!
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Joined: Oct 2001
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From: SF Bay Area, CA
Same as W12 set up; net you can just pull the vacuum lines
The valves "fail" to the open position without vacuum. Thus just pulling the hoses opens the valves permanently. The hoses don't seem to be tied to any CEL warning issue either, though it's simple just to plug the hose end.
I tried this on the W12 and it did increase the exhaust noise a bit, and w/ out other issues of any note. But, I ended up putting it back to stock, figuring on an NA engine, greater back pressure (ie. flaps closed in lower RPM range) typically increases torque. Presumably among the reasons the factory set it up that way.
I tried this on the W12 and it did increase the exhaust noise a bit, and w/ out other issues of any note. But, I ended up putting it back to stock, figuring on an NA engine, greater back pressure (ie. flaps closed in lower RPM range) typically increases torque. Presumably among the reasons the factory set it up that way.
AudiWorld Member
Joined: Nov 2010
Posts: 403
Likes: 3
From: MHT, HYA
The valves "fail" to the open position without vacuum. Thus just pulling the hoses opens the valves permanently. The hoses don't seem to be tied to any CEL warning issue either, though it's simple just to plug the hose end.
I tried this on the W12 and it did increase the exhaust noise a bit, and w/ out other issues of any note. But, I ended up putting it back to stock, figuring on an NA engine, greater back pressure (ie. flaps closed in lower RPM range) typically increases torque. Presumably among the reasons the factory set it up that way.
I tried this on the W12 and it did increase the exhaust noise a bit, and w/ out other issues of any note. But, I ended up putting it back to stock, figuring on an NA engine, greater back pressure (ie. flaps closed in lower RPM range) typically increases torque. Presumably among the reasons the factory set it up that way.
I toyed with the idea of installing a switch that I could use to toggle the opening, but ended up cutting eyelet brackets into more of a C shape, and pinned the valve arm to the open position by bolting the machine threaded end through a hole in a nearby bracket.
I'll add a picture tomorrow.
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