Exhaust flap continually open findings

[Paulm]

I have run around 300 miles with the flaps open.

Sounds much better, you can hear the exhaust all the time but not intrusive. When running around 50 or 60 and it goes into 4 cylinder mode the drone is deffo louder than standard but again nothing bad. Even when standard that noise annoyed me, the tone is different now and weirdly not so annoying on my ears.

The plus side as it gives an easy +2 mpg. I guess the standard pipe is pretty restrictive when the flaps are closed. No real difference when nailing it as the flaps will be open anyway but wafting around (town and rubbish "A" roads) I continually see over 22mpg I used to see 19 ish before.

Pops and bangs on overrun are deffo louder, I wonder if they only open a certain % in standard form. Sound loud and mean now.

anyway not found any downside as yet.

[Lewy]

Paul,

How do you secure the flaps open at all times? Is it a similar trick to the "brown lead on the Porsche PSE" fix?

Cheers
Lewy

[Markp]

10% improvement in economy.
Sorry, don't buy that the improvement is anything to do with the exhaust.
Perhaps you are being gentler with your right foot

[MikeFish]

Paul,

How do you secure the flaps open at all times? Is it a similar trick to the "brown lead on the Porsche PSE" fix?

Cheers
Lewy

Just unplug the electrical connector on each valve. Tape them up to stop them filling with crap.

[Paulm]

10% improvement in economy.
Sorry, don't buy that the improvement is anything to do with the exhaust.
Perhaps you are being gentler with your right foot

yeah I am a habitable liar.

I am not selling anything I just write what I see.

[Paulm]

Paul,

How do you secure the flaps open at all times? Is it a similar trick to the "brown lead on the Porsche PSE" fix?

Cheers
Lewy

What Mike said. pretty strong spring that keeps them open

[Lewy]

Any pictures to guide me gents?

[Markp]

10% improvement in economy.
Sorry, don't buy that the improvement is anything to do with the exhaust.
Perhaps you are being gentler with your right foot

yeah I am a habitable liar.

I am not selling anything I just write what I see.

Not suggesting you are lying - just that I don't think tying back the flaps could possibly boost engine efficiency by that much. Causation versus association.
But didn't mean to upset you so let's leave it there.

[Andy_W]

Certainly sounds better with the valves open. I've not really noticed and difference with cylinder deactivation other than sometimes it doesn't sound as loud. Presume putting it in sports forces all 8 cylinders on anyway. Sport manual is the place to be
I would still like it to be about 15-20% louder but do t really want to go aftermarket unless I've heard and been in one first. Been caught out a few times with the videos sounding better than the real thing

[Paulm]

10% improvement in economy.
Sorry, don't buy that the improvement is anything to do with the exhaust.
Perhaps you are being gentler with your right foot

yeah I am a habitable liar.

I am not selling anything I just write what I see.

Not suggesting you are lying - just that I don't think tying back the flaps could possibly boost engine efficiency by that much. Causation versus association.
But didn't mean to upset you so let's leave it there.

I apologise, my post seems a bit nippy

I will see if I can find some time and do real testing. I will do a run at say 70mph in cruise control, no flaps, then same run with flaps. Not very scientific but will give a good idea. might try 50mpg as well as its mainly town and A road stuff I do. I did 150mile round trip yesterday and got 22.6mpg, rubbish roads (back roads, to Huntley, Banchory, Stonhaven) drove steady there but was in a bit of a hurry the last 40 miles home so tramped on a bit. 22.6 just seems high compared what I am used to.

Opening the flaps will have an effect on ignition timing (it can run more) and the Audi will as much timing as it can (or is mapped to ) I hear what you are saying re my foot and it may well be all in the mind. Will test and see when I get time. if I am speaking rubbish I will be the fist to say!!

[Paulm]

Any pictures to guide me gents?

yes but not very good ones

[MikeFish]

Any pictures to guide me gents?

I dare say photos are not required. There is a plug on each valve. Disconnect it. The valves are at the business end of the exhaust i.e. the tailpipes just behind the rear silencers.
I think there were some photos on here but I doubt it'll help you much. If you know where the valves are then you are almost done.

Edit: I just noticed there are photos in the post above!

[Markp]

I apologise, my post seems a bit nippy

I will see if I can find some time and do real testing. I will do a run at say 70mph in cruise control, no flaps, then same run with flaps. Not very scientific but will give a good idea. might try 50mpg as well as its mainly town and A road stuff I do. I did 150mile round trip yesterday and got 22.6mpg, rubbish roads (back roads, to Huntley, Banchory, Stonhaven) drove steady there but was in a bit of a hurry the last 40 miles home so tramped on a bit. 22.6 just seems high compared what I am used to.

Opening the flaps will have an effect on ignition timing (it can run more) and the Audi will as much timing as it can (or is mapped to ) I hear what you are saying re my foot and it may well be all in the mind. Will test and see when I get time. if I am speaking rubbish I will be the fist to say!![/quote]


All good

[wildbore]

Interesting topic. As with all real-world driving,it is difficult to accurately compare one journey to another in terms of consumption, but I was doing a weekly 400 mile round trip - all motorway and always on ACC at the same set speed - for several months last year. I did the trip several times with the exhaust in dynamic and then several more times with it in Comfort. I found a definite improvement in fuel economy with the exhaust in Comfort. Also, at 85 the exhaust has a constant background rumble in Dynamic, but it's whisper-quiet in Comfort.

[Markp]

Wildbore - so that is the opposite of Paul's experience...