Stock S4 Exhaust Valving?

[Cargo8]

I was wondering if anyone knew if there is any sort of valve on the stock B7 S4 exhaust.

It seems to me that at around 3000 rpm the exhaust sound richens up a lot, more so than a consistent exhaust system which is standard all through the rev range would.

It could be in my head though. Anyone know for certain?

[ps. I searched and read a thread which discussed how the B6 exhaust before 2004 was actually reduced in sound by the mufflers above 1700 rpm, but I think that is something different entirely]

[V8weight]

don't quote me on this, I think there is a vacuum solenoid on each muffler that opens up an additional exhaust passage before the tip around 3000rpm. your higher vacuum between idle to 3000rpm holds the valve shut, than as rpm increases, the valve opens up. Its not in your head, the volume should increase at 3000 rpm. I'm trying to figure out if I was to add a vacuum limiter inline before each solenoid, if the valve will open at a lower rpm. anybody feel free to chime in with opinions. I know the reasoning is to build low end torque.

[fitzS4]

yes there is a vacume line...i unplugged mine and it sounds nice for 2 minutes of work........i believe it is for "drone" affect so you dont get drowned with that los sound.....if i remember correctly

[Cargo8]

DIY to unplug? And easy to undo (replug)?

[V8weight]

if you roll under your rear bumper and look behind the exhaust tips, the vacuum lines are easy to see. just pull them off, and FIND SOMETHING TO PLUG THEM WITH. a small bolt would work. But if you don't plug them, you will have a vacuum leak. Easy DIY.

[Justincredible]

you will see the valve. Just look at the mufflers from behind the car. The valve open and closes to keep the exhaust tone in check down low. Once you see it the whole thing is kinda cut and dry easy. But if you still have questions post them up.

IMHO leave the valve in until you replace the exhaust. Its not like it is robing the car of any REAL power.

[Samster]

So basically unplugging that vac lines will make the sound louder without doing any damage to the exhaust system? If so, sounds good. lol

[Justincredible]

So basically unplugging that vac lines will make the sound louder without doing any damage to the exhaust system? If so, sounds good. lol

Yes just make sure to tend to the Vac lines

[boravr6]

any before and after sound clips?

[Cargo8]

I'd love to hear an open valved video if anyone does it

[J.the W.]

Can someone please post a pic of the valve. I know the RS4 has an exhaust valve but I don't think the B7 S4 has one. I looked on my car and could not find any kind of valve under there.

[EnjoyIncs]

here is the valve on a B6

http://cgi.ebay.com/ebaymotors/AUDI-...Q5fAccessories

I know the bmw 335 has a valve and it makes a huge diff in the sound when it is always open. Normally it would only open at full throttle. All you have to do is put a small hose clamp on the vacuum line and it will stay open all the time.

[hayasa]

Just replaced my cat-back on my B7 S4. No valve at all (external) unless something else is going on in the muffler that I can't see. (BTW, I installed the Corsa exhaust one of the members here was selling. Sounds *mean*.)

[...Mark...]

here is the valve on a B6

Post a bigger version of the bottom pic please.

[J.the W.]

The B7 exhaust is different. I looked at the Ebay pics and saw the valve.

[MOFSTEEL]

The B7 exhaust is different. I looked at the Ebay pics and saw the valve.

+1 No valves on the B7

[EnjoyIncs]

Post a bigger version of the bottom pic please.

That pic is of a VW. I was just using it as an example. And I don't have a bigger one.

[...Mark...]

I was being lazy.. I went outside and saw what you are taking about.. Looks like i'm stopping by H.D. tonight on my way home to get something to clamp those up.

[EnjoyIncs]

I hope it wont throw a CEL. Also the bmw guys say it takes longer for their cars to warm up due to less back pressure when the valves are open.

[Cargo8]

The golf tee mod you are talking about (for hte 335i) is not exactly what you say (unless you're speaking of something else). The golftee mod as they call it makes the exhaust come out both piipes all the time, whereas usually it only comes out hte left on the 335i until about 3000 rpm or something

[EnjoyIncs]

The golf tee mod you are talking about (for hte 335i) is not exactly what you say (unless you're speaking of something else). The golftee mod as they call it makes the exhaust come out both piipes all the time, whereas usually it only comes out hte left on the 335i until about 3000 rpm or something

Could you please explain? I thought the way it worked on the B6 was very similar.

Valves are closed until a certain rpm / blocking the vacuum line lets them stay open all the time.

[fitzS4]

i dont know specifics but they give more raspy sound when under hard throttle...it will not throw a CEL because one of my plugs fell off for like a month and nothing happend so it will not do anything to the car....this is very common in the R32's

[EnjoyIncs]

I was being lazy.. I went outside and saw what you are taking about.. Looks like i'm stopping by H.D. tonight on my way home to get something to clamp those up.

Did you stop at the store? Could you do a before and after sound/video clip?

[...Mark...]

Did you stop at the store? Could you do a before and after sound/video clip?

I did, and no i can't because i don't have a video cam. Sorry..

Like others said, its noticable under throttle, but to be honest if i didn't know what it sounded like before i may have thought it was stock especially at idle. Its just a little more audible, kinda like the 350Z/G35 cars when they are under a load but w/ a V8 grunt to it rather than the Nissan raspy sound. Its louder than stock but not by much.

Try it out, its a free mod, and if you don't like it its easy enought to switch back.. It takes 15 minutes.

[GotRS?]

If this is like the R32 you will lose a load of low end torque. It's not just a noise thing.
Suck it and see.

[EnjoyIncs]

I did, and no i can't because i don't have a video cam. Sorry..

Like others said, its noticable under throttle, but to be honest if i didn't know what it sounded like before i may have thought it was stock especially at idle. Its just a little more audible, kinda like the 350Z/G35 cars when they are under a load but w/ a V8 grunt to it rather than the Nissan raspy sound. Its louder than stock but not by much.

Try it out, its a free mod, and if you don't like it its easy enought to switch back.. It takes 15 minutes.

What type of clamp did you use?

[...Mark...]

What type of clamp did you use?

I had a wooden dowel laying aroung the garage. I just cut it to the length that i needed which was about an inch long, grabbed the hose w/ one set up pliers and pushed the cut piece of the dowel in with another. I took a blade to one end of the dowel to make a little of a point w/ it so that it was easier going in.

[sakimano]

what a funny thread

[momoney]

+1 No valves on the B7

+2 I dont have a valve on my exhaust unless i am not looking at the right spot

[BsixSfour]

+2 I dont have a valve on my exhaust unless i am not looking at the right spot

Either I'm blind, or the B6's don't have it either