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I have had my RS4 for just over a week now and 1000 miles and it was back at the dealer for the last few days having its seat reskinned. Meanwhile I had an Audi S5 as a replacement and unlike the two other S5s I had driven in the past this was much better. Most worrying was the fact that it felt more torquey than my RS4 and generally quicker, until I used all of the revs in the RS4.

For anyone who hasn't driven an S5, it is a lovely place to sit, has these great LED DRLs and draws plenty of attention on the road. Downsides are a sloppy gearchange, driveline shunt, inconsistently weighted power steering and an engine that (in my past experience) usually runs out of power beyond mid-range.

This one didn't. It made a great noise, pulled with real urgency and authority in 5th and 6th gears and made me feel rather doubtful of the wisdom in choosing an RS4. Thankfully it undermined this indomitable display as soon as I tacked a twisty back road. That's the time when the S5 shows most clearly that it is a GT car and not a sports car, but I still came away dissapointed that it could make me doubt my RS4.

So I fiddled around last night and decided to disconnect the exhaust valves and see what difference that made. Oh my! What the hell are Audi doing with those exhaust valves.

I had been wondering why the EVO long-termer that I drove to Spain had felt different to my RS4 Avant, and now I know why. It must have had its exhaust valves similarly disconnected. It's like removing a banana that some kid had stuck there as a prank, now the engine breathes, revs cleanly through the gears, sounds the same as the EVO long-termer and behaves identically by triggering TC when changing up from 1st to 2nd at high revs.

It's now a whole different car, noticeably quicker, much easier to drive, louder (in a good way) and a whole lot more appealing. And clearly better than the S5 I had been driving these past few days.

I'm glad I did this, and if anyone else like me was wondering if it was worth doing then wonder no more.

Your so damm right..........

Dont know what it is, but after disconnecting the actuator pipes and plugging all holes, there is something different about it. The sligh noise increase is good, bt it feels more than that.....

J

Quite tempted to do this on my car - but didnt the Evo longtermer have a miltek exhaust ?

Do the rs4 flaps with s button pressed mean that they are open all the time or is the rs4 system like porsches in that they open initially and close when the revs rise? If this is the case then I pressume that clamping the hoses makes it louder on the move. Anyone know?

b7sedan wrote:Do the rs4 flaps with s button pressed mean that they are open all the time or is the rs4 system like porsches in that they open initially and close when the revs rise? If this is the case then I pressume that clamping the hoses makes it louder on the move. Anyone know?

Unlike the PSE, with "S" pressed they're open all the time. DoctorD how is this done and can it cause long term damage to the valves?

LE

also interested to hear how this is achieved.

In that case its pointless disconncting the valves then surely, unless you cant be arsed to press teh s button, or is dr d saying that you actually remove something else. Confused

LegalEagle wrote:

b7sedan wrote:Do the rs4 flaps with s button pressed mean that they are open all the time or is the rs4 system like porsches in that they open initially and close when the revs rise? If this is the case then I pressume that clamping the hoses makes it louder on the move. Anyone know?

Unlike the PSE, with "S" pressed they're open all the time. DoctorD how is this done and can it cause long term damage to the valves?

LE

LegalEagle,
Even with the sport button on, the valves are not open all the time.They are open at tick over, then shut at around 1100rpm, then re-open at around 3700rpm.As with the PSE, its something to do with noise limits at around 30 -40 mph.All you have to do is to pull the vacuum pipes off the vacuum units on the tail pipes, and then clamp the hoses, and cover the vacuum units intakes, to stop any muck entering.Regards, SIMON.

Thanks Simon, any idiot proof photos/links?

LE

Cheers Simon, you beat me to it. I was just searching for this...

RSjd wrote:Non Sport mode:
exhaust flaps stay shut until 5,000k rpm in 1st, 2nd, 3rd gear.
exhaust flaps stay shut until 4,500k rpm in 4th, 5th, 6st gear.
throttle 50-60 % open till 5,500 rpm in 1st, 2nd, 3rd
throttle 100% open 0-8,250 rpm in 4th, 5th, 6th

Sport mode:
exhaust flaps open at idling 760rpm
exhaust flaps shut from 1,000k rpm until 3,700k rpm in 1st, 2nd, 3rd
exhaust flaps open ALL the time from 0-8250rpm in 4th, 5th, 6st gear.
throttle 50-60 % open till 5,500 rpm in 1st, 2nd, 3rd
throttle 100% open 0-8,250 rpm in 4th, 5th, 6th


So throttle is the same in both modes !

Holy Sh!t.

This is very interesting. This makes sense to me as I see my car having a "surge" of power up the gears at around 5,500 rpm all the way to 8,000rpm - that must be the valves opening?

At idle I could see them open, but had no idea they closed again. So I assume that the hose disconnected leaves the valves open all the time, rather than shut, or is there a procedure to ensure you disconnect the pipe when the valve is open etc etc?

So it seems bullet proof for an idoit like me PippyRips, if you do it can you reply with your thoughts? Might give this a go at the weekend. Any things to be careful of rather than clamping and covering? Again, longer term effects?

Cheers!!
Ró

Will do Ro - as i will be trying it out for myself.

DoctorD - what did you use for clamps and also to block the value feed into the exhaust?

What my mate done was cut the pipe in half and then got 2 small bolts for each side, put them up the pipes and used 2 little clamps that he got from a VW dealer that are used as the fix for the rear window washer pipe comming apart from where it conects to the washer nozzel in the hatch.

pippyrips wrote:also interested to hear how this is achieved.

See here;-
http://www.rs246.com/index.php?name=PNp ... 98&start=0

If you have to block off the pipe and you have to cover where the pipe sits then instead of thinking of using a clamp and other complicated ways why not tie the pipe in a knot and re attach. Or is that not going to work.