03-14-2013, 12:14 PM | #23 |
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Ok so hopefully this one we can pu to rest
Here's some background info on how the magic exhaust valve works The exhaust flap reduces the noise level when the engine is idle and when the engine speed is close to idle. This reduces the outlet noise to improve comfort for the customer. The reduction in outlet noise is appr 8db . The engine control activates the exhaust valve. The degree of opening depends on gear, engine load and engine speed (see chart below). Only two conditions , open and closed, occur while driving. Index 1 Gear Engaged 2 Exhaust flap , closed 3 Exhaust flap, closed 4 Data point for engine speed If the exhaust flap is faulty (or tempered with) the exhaust system will emit a hissing noise at high engine speeds when it's closed. If the exhaust flap is defective and partially open a humming noise will be generated at idle. Case closed
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03-14-2013, 12:17 PM | #24 |
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Well that puts a decisive end to that!
Just making sure this is read correctly...To clarify (and correct me if I am wrong) the exhaust valves being wired open has no side effects other than louder note (slightly). That was my experience. There si no hissing or humming whatsoever. Now having modified OEM without valves and different piping it sounds fantastic. |
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03-14-2013, 12:41 PM | #25 | |
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Correct (on the side effects) I think the hissing/humming is something some very sensitive drivers might hear. Probably not folks looking for a more pronounced exhaust note
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03-14-2013, 01:10 PM | #26 | |
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03-16-2013, 03:50 AM | #27 | |
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03-16-2013, 06:34 PM | #28 |
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Guys, I just completed the valve opening mod and it's a nice improvement in sound. It took me about 30 minutes all in and I can notice the difference, especially at lower RPMs. If I can swing another 8-10db via some other mod, the exhaust would be perfect! My butt dyno also noticed a slight increase in response at lower RPMs, but that could be in my head...or butt.
Thanks for the detailed explanation!!
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03-17-2013, 06:38 AM | #29 | |
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I didn't notice any change in response. |
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03-18-2013, 07:36 PM | #30 | |
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03-19-2013, 04:14 AM | #31 | |
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What does Ron actually do to the rear silencers ?. Does he open them up, and cover up the holes in the baffles, just like the E92 M3 mod ?, thankyou, regards, SIMON. |
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03-19-2013, 06:05 AM | #33 | |
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03-19-2013, 06:58 AM | #34 | |
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Yes, it makes sense. They will be removing the very short baffled pipes inside the rear silencers, effectively, making the exhaust a straight through version, so more noise. I bet it sounds very good, and not a £million to do, regards, SIMON. |
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03-20-2013, 07:06 PM | #35 |
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Yep. It sounds like a deeper throaty V8. Very nice.
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04-20-2013, 02:21 AM | #36 |
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Btw you can also modify the vacuum setup so the exhaust valves are ALWAYS open , no need to use chicken/barb wire at all. Looks OEM and works perfectly. Over night the valves will close (loosing vacuum) but as soon as you start the engine they'll be open again.
I will take some detailed pictures/info when I get back from my trip next weekend.
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04-20-2013, 11:04 AM | #37 | |
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04-21-2013, 04:38 PM | #38 | ||
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05-11-2013, 02:44 AM | #39 | |
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05-11-2013, 03:17 AM | #40 | |
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05-11-2013, 06:11 AM | #41 |
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Ive watched these valves, over the couple of months ive owned the car, and all i can see, is that the valves are closed, for a couple of minutes, during warm up, and then open from then onwards. So, all i can see these valves are used for, is for helping the cats, and the engine to warm up quicker ?. They are open all the time when the car is up to temp. So i dont really see the point of wiring them open, because they are always open anyway, when warm, regards, SIMON.
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05-11-2013, 09:54 AM | #42 | |
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05-11-2013, 10:34 AM | #43 | |
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If you're worried about the engine warming up, touch the steel lines on top of the engine after it's been running for a minute....
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05-11-2013, 10:41 AM | #44 | |
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Because if so why bother strapping them open.
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