Exhaust flap Audi S3

prt57

Registered User
Hi,
Just thinking about all the different aftermarket exhaust options at the moment. My son has a Milltek non resonated cat back on his Golf 7R. It makes some good noises in sport mode but it is annoying on the motorway. Put your foot down at motorway speeds and you get a very loud drone.
The standard S3 exhaust has the flap that opens at approx. 3000 rpm. Is the flap operated electrically or via vacuum?
Cheers,
Peter
 

leshkin

Hold my beer...
VCDS Map User
On S3s, it's an electrical solenoid that operates it at 3k rpm, if my memory serves me right. The only vacuum system that I know of, and have been using myself for well over a year now, is the BCS Powervalve system. This taps the vacuum line in the engine bay and a pipe is then run to the rear silencer.

In terms of performance, the stock S3 setup is done purely for sound and has little to none performance benefit as it sits after the backbox. BCS system on the other hand is a full 3" form turbo to the the end, with a 3" valve that will bypass the backbox completely once you are on boost.

If you are interested in performance and sound, then BCS is the way to go - just search here for more info. If you just want a mroe agressive sound from a stock pipe, then see here: http://www.audi-sport.net/xf/threads/how-to-s3-exhaust-flap-mod.64998/
 

prt57

Registered User
Hi Leshkin,
Thank you for your reply and information.
Thinking of the BCS , is the sound progressive once the valve opens or is it just off then on.
What does it sound like when slowing down? Does it burble or pop at all?
I have watched as many power valve videos as possible but you cannot gauge exactly what it is like compared to Being there.
What is it like at 70mph on the motor way. Will it drone when putting your foot down like the non res cat back on my son's golf7R?
All thoughts welcomed.

Peter
 

leshkin

Hold my beer...
VCDS Map User
OK, so it does not drone whatever the speed. BCS make a big point about that - it's tuned correctly.

As far as the valve goes, then it is a bit of an on/off when it comes to sound. There is a little collar that can be put on it that will stop the valve from closing completely and that will give you the pops and burbles. I like the way it works out of the box personally - use my car for school runs, grocery shopping as well as spirited Sunday morning drives, so having a stock-sounding option is nice :)

Edit: When the valve is open, the sound is very nice, but again, it doesn't drone - once up to cruising speed it goes pretty quiet.
 

prt57

Registered User
Thanks for the update. I may go up to BCS in a couple of weeks as I would like to hear a Power Valve exhaust before I order. I will call to see if they have a demo car.
In the mean time, I am having an APR 1+ on Thursday and so looking forward to that!

Peter
 

leshkin

Hold my beer...
VCDS Map User
Thanks for the update. I may go up to BCS in a couple of weeks as I would like to hear a Power Valve exhaust before I order. I will call to see if they have a demo car.
In the mean time, I am having an APR 1+ on Thursday and so looking forward to that!

Peter
If you want to hear what BCS pipe sounds like, you might be better off speaking to someone local who has it or meet up at a show... I'm in West London if that helps.

The exhaust farts on WOT and DSG are epic! :)
 

prt57

Registered User
Thank you for your kind offer Leshkin but I am in the Midlands. I have some business up in Lancashire which is why I can pop into St Helens.
However, I will keep my eyes open for someone based near here.
My car is a manual, will it still fart!?
On my son's Golf7R it really cracks with quite a loud bang going up the gears in Sport mode.

Peter
 

Smirky

Registered User
You won't get a fart from it in a manual just can't shift quick enough ,
 

drunknspikes3

Member
VCDS Map User
Hi,
Just thinking about all the different aftermarket exhaust options at the moment. My son has a Milltek non resonated cat back on his Golf 7R. It makes some good noises in sport mode but it is annoying on the motorway. Put your foot down at motorway speeds and you get a very loud drone.
The standard S3 exhaust has the flap that opens at approx. 3000 rpm. Is the flap operated electrically or via vacuum?
Cheers,
Peter
what year is your s3 ? didnt know they had an exhaust flap ? mines a 2007
 

HHS3

Phantom Black S3 - R-Tech Stage 2+
2007 S3 has the exhaust flap.

Didn't realise this existed so thank you for bringing it to my attention as I'll be doing the mod soon (thanks @leshkin for the link) to keep the flap permanently open . When I go stage 2+ I won't be able to afford a turbo back exhaust and so I'll just be getting the BCS Powervalve downpipe & decat at first as this is the most restrictive section, the cat back can wait till a later date as it doesn't make much of a difference compared to getting the downpipe done.

I am having an APR 1+ on Thursday and so looking forward to that!

Let us know your thoughts on the APR stage 1+ remap after some usage, I haven't seen or read of anyone else doing this so will be interesting to see the difference.
 

prt57

Registered User
APR 1+ being fitted as I type this!!

I hope that it goes well. The guys at VRS are certainly taking care of my car. Lots of protective paper mats and plastic seat covers in evidence.
 

HHS3

Phantom Black S3 - R-Tech Stage 2+
APR 1+ being fitted as I type this!!

I hope that it goes well. The guys at VRS are certainly taking care of my car. Lots of protective paper mats and plastic seat covers in evidence.

Sounds good mate, are you getting anything else done or just the remap and HPFP for now?

I'm happy with my Revo stage 1 remap and Revo CAI (Camcoated) so I'm sure you'll enjoy the extra power as well.

I was having a look on another forum about remaps of which I came across an interesting read from an APR employee:

Stage 1: Remap only.
Stage 1+: Remap + fuelling system component change (injectors or High Pressure Fuel Pump). All "plus" stages indicate a change to the fuelling components.
Stage 2: "Testpipe file." Requires remap + sports catalyst or decatted downpipe at minimum. Also includes turboback exhaust.
Stage 2+: "Testpipe file." Requires remap + sport/decat downpipe + fuelling component change.
K04: Software for K04 upgrades on transverse 1.8t/2.0t solutions. We sell this separately but only if the auxillary components match those of our K04 kits.
Stage 3: Big turbo software. Requires APR turbo kit. APR stage 3 software is only provided with the purchase of an APR stage 3 turbo kit.
Stage 3+: Big turbo software. Requires APR turbo kit and additional APR-supplied components.
Stage 4: Complete APR-built and modified engine + Big turbo kit/software.

NOTE: Induction Kits, Diverter Valves, Clutches, Upgraded Hoses, Front Mount Intercoolers and Cat-back exhaust systems do not affect the calibration of our stages above as their benefits are automatically calculated and adjusted by the ECU. These components can be present at any level without changing the name of the stage.
 

prt57

Registered User
Hi,
At the same time as the 1+ the pcv valve is being changed along with a new set of plugs. I already have a DV+. It was running a Superchips stage 1 map which I took off before my trip to Northampton. Definitely felt more sluggish back at stock. As I am keen to maintain the OE appearance I am having a VWR panel filter. Maybe a CAI later if needed. To try and improve flow in the OE air box I have smoothed as much as possible to remove as many bits of unnessary plastic supports or sticking up parts. Probably a waste of time but as least it kept me busy for a couple of hours!!
 

prt57

Registered User
Bearing in mind standard exhaust and OE intake it made
324.4 Hp and 342.6 ft.lbs.
Driving home soon - getting quite excited!
 

HHS3

Phantom Black S3 - R-Tech Stage 2+
Hi,
At the same time as the 1+ the pcv valve is being changed along with a new set of plugs. I already have a DV+.

Bearing in mind standard exhaust and OE intake it made
324.4 Hp and 342.6 ft.lbs.
Driving home soon - getting quite excited!

That's good you've got the revised PCV valve done as well, my old one went last year and it was embarrassing sitting in traffic with the engine revving when idle! Nice that you've got the GFB DV+ already, I'll definitely be getting that when I go Stage 2+.

You've got some good results there mate, not bad at all considering stage 2 barely makes anymore than that, upload a pic of the RR graph if you can. Torque is where you can really tell the difference, just wait for the drive home haha!
 

Smirky

Registered User
Some high numbers there I'm looking forward to seeing what mine puts out on one of these dynos that produce high numbers
 

scotty dugg

Active Member
Silver Supporter
I noticed my S3 (57' Plate) had a solenoid on it the other week, I can hear it close after revving at a standstill.

Think I may give it a go and see if it's any noisier, I can't afford a new exhaust at the moment. If anyone else does it update this thread with your findings please :)
 

HHS3

Phantom Black S3 - R-Tech Stage 2+
I noticed my S3 (57' Plate) had a solenoid on it the other week, I can hear it close after revving at a standstill.

Think I may give it a go and see if it's any noisier, I can't afford a new exhaust at the moment. If anyone else does it update this thread with your findings please :)

Me being impulsive as ever will be popping to Halfords after work today to see if they have any of the locking wire mentioned in another thread and then hopefully give this a go, as long as I can reach the flap without the car being raised that is.

I'll let you know how I get on mate. From what I've read on other threads about this, is that it's not a huge improvement so don't expect it to be burbling and spitting like an aftermarket exhaust, however there is a slightly noticeable difference so you can't complain for a free 5 minute mod I suppose.

Threads:

http://www.audi-sport.net/xf/threads/how-to-s3-exhaust-flap-mod.64998/
http://www.audi-sport.net/xf/threads/exhaust-mod.42546/
 
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prt57

Registered User
Home now and very pleased with the results. I am not a rev the nuts off sort of chap but it really goes well. Rev limit raised to 7100 I believe but I am more than happy up to 6000 rpm. You can really feel the torque accelerating you forward from under 3000 rpm with the peak at 4000 rpm and then onwards.
The Superchips I had before was much better than stock but this is in a different league again. Torque is better than advertised on the APR site but power lower due to having the standard intake.
VWR filter much better than the Pipercross I had in originally. If you could compress all the mesh together on the Pipercross it will take up at least 0.25 of the filter area thus reducing air flow. VWR filter supported by squared metal mesh but much more open.
VRS staff excellent and they really took care of my car, so well done to them!
P.
 

HHS3

Phantom Black S3 - R-Tech Stage 2+
Think I may give it a go and see if it's any noisier, I can't afford a new exhaust at the moment. If anyone else does it update this thread with your findings please :)

I popped to Halfords after work yesterday and bought some 0.6mm wire to do the job which I picked up for £6, I also bought a socket to undo the rear wiper bolt as I wanted to de-wiper my car as well.

Doing the exhaust flap was straight forward using this guide http://www.audi-sport.net/xf/threads/how-to-s3-exhaust-flap-mod.64998/. The only issue I had was that I didn't have a ramp or planks to raise the rear, so it was very awkward trying to work underneath the car with very little room. I used a flat-head screwdriver and long nose pliers to pop the lever out of the actuator arm and pushed the actuator arm so it's in a 5 o clock position, as this is the optimal angle for the valve to be fully open (you can check in the left exhaust pipe). Then just feed the wire through the actuator arm and wrap around the mount a couple of times before feeding back through the actuator arm and finally twist both ends around each other a good few times, cut off any excess wire, job done.

Regarding the difference in sound, it is negligible if I'm being completely honest but there was a couple of times where I did notice it was a tad louder when coming off throttle to be fair, so for an easy, free 10 minute job (quicker if the rear is raised), then you can't complain. I imagine it would probably make a bit more of a difference if you had an aftermarket downpipe with sports/decat done as well.

Home now and very pleased with the results. I am not a rev the nuts off sort of chap but it really goes well. Rev limit raised to 7100 I believe but I am more than happy up to 6000 rpm. You can really feel the torque accelerating you forward from under 3000 rpm with the peak at 4000 rpm and then onwards.
The Superchips I had before was much better than stock but this is in a different league again. Torque is better than advertised on the APR site but power lower due to having the standard intake.
VWR filter much better than the Pipercross I had in originally. If you could compress all the mesh together on the Pipercross it will take up at least 0.25 of the filter area thus reducing air flow. VWR filter supported by squared metal mesh but much more open.
VRS staff excellent and they really took care of my car, so well done to them!
P.

Glad you're happy with the result mate, it does make the car a lot more fun to drive! For stage 1 a CAI isn't essential, stage 2 benefits from it and it's a must for stage 2+ onwards. Even if you plan on staying at stage 1 then I still do fully recommend getting a CAI at some point, I've had my Revo CAI (Camcoated) for month now and I absolutely love it, the noise it makes is fantastic and it does give small gains as well.
 
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prt57

Registered User
I can see where the CAI would benefit looking at the graph as the power tails off earlier than expected with it hitting 324.4 bhp at 5600 rpm. Lots of people have said the standard air box holds it back at high revs but I prefer the OEM appearance (at the moment!)
However the torque due to the Loba hpfp is amazing and very useable without thrashing it to death!!
 

HHS3

Phantom Black S3 - R-Tech Stage 2+
I can see where the CAI would benefit looking at the graph as the power tails off earlier than expected with it hitting 324.4 bhp at 5600 rpm. Lots of people have said the standard air box holds it back at high revs but I prefer the OEM appearance (at the moment!)
However the torque due to the Loba hpfp is amazing and very useable without thrashing it to death!!

That's fair enough, I do appreciate the importance of OEM appearance, especially on classy cars as there's nothing worse then a chavved out motor! I can assure you though that there isn't nothing chavvy about a CAI on the S3 as Audi's use a diverter valve rather than a dump valve, the suction noise generated by the CAI is awesome finished off by a sporty sounding svvvvstsh is mint! If the day does come where you decide to get a CAI then go either Revo or ITG as they're the best, owners of the ITG (e.g. S3Alex) say that it doesn't look the prettiest and I personally prefer the appearance of the Revo as well, plus they do a powder coat version or camcoated version for an extra £100.

Sounds good about the Loba HPFP, wish I could have mine done sooner but my clutch is barely coping as it is! So stage 2+ will have to wait until I save up £2K for the essential parts, let alone labour on top of that, then the beneficial parts like coilovers, arb's & alk can come at a later date.
 

scotty dugg

Active Member
Silver Supporter
I popped to Halfords after work yesterday and bought some 0.6mm wire to do the job which I picked up for £6, I also bought a socket to undo the rear wiper bolt as I wanted to de-wiper my car as well.

Doing the exhaust flap was straight forward using this guide http://www.audi-sport.net/xf/threads/how-to-s3-exhaust-flap-mod.64998/. The only issue I had was that I didn't have a ramp or planks to raise the rear, so it was very awkward trying to work underneath the car with very little room. I used a flat-head screwdriver and long nose pliers to pop the lever out of the actuator arm and pushed the actuator arm so it's in a 5 o clock position, as this is the optimal angle for the valve to be fully open (you can check in the left exhaust pipe). Then just feed the wire through the actuator arm and wrap around the mount a couple of times before feeding back through the actuator arm and finally twist both ends around each other a good few times, cut off any excess wire, job done.

Regarding the difference in sound, it is negligible if I'm being completely honest but there was a couple of times where I did notice it was a tad louder when coming off throttle to be fair, so for an easy, free 10 minute job (quicker if the rear is raised), then you can't complain. I imagine it would probably make a bit more of a difference if you had an aftermarket downpipe with sports/decat done as well.

Cheers mate, sounds like a very easy mod, certainly reversible if you end up not liking it. I'll give it a shot next time I have a chance.
 

HHS3

Phantom Black S3 - R-Tech Stage 2+
Cheers mate, sounds like a very easy mod, certainly reversible if you end up not liking it. I'll give it a shot next time I have a chance.

No worries bud, I'm no mechanic by any means but as long as I've got a guide with pictures to follow then I'm ok, I also managed to successfully de-wiper my car as well! Yeah exactly, it's easy to do and even easier to undo so you lose nothing by giving it a go.
 

lincoln_dj

Active Member
VCDS Map User
I went full turbo-back milltek so lost the flap. I went resonated though so rarely get any droning but still sounds nice at low revs. I'm not really interested in how it sounds though tbh, did it purely from a performance point of view. far too old to be driving round setting off alarms now!!
 
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