How noisy is a non res, non valved miltek?

[Stevec33]

Ive been offerd a non res non valved miltek and considering buying it. However i dont want to spoil the car by putting a very noisy exhaust on it if that makes sense, i want more noise but not so much that is drones all the time and is generally just too loud. Whats peoples opinion who own one? Are they loads louded or just nicely louder? Cheers

[toyneg]

they are quite a bit louder mate, you can learn to drive around the drone but it's much louder than the standard set up, and without the valves you can't shut it up on the occasions you want to. where are you based? ideally you should get someone who has one to show you before you commit. from the outside of the car on full chat it is considerably louder

[HYFR]

You can easily swap out the centre pipe to a res pipe and sell the non res bit

[PetrolDave]

i want more noise but not so much that is drones all the time and is generally just too loud.

I had a non-res valved fitted by MRC and like the increase in volume EXCEPT for the drone between 1000-2200rpm which I found totally unacceptable as I had to completely change my driving style to avoid it. So as soon as this dreadful weather abates I'm off to MRC to have the non-res centre section swapped to a res version.

[C5ARK_RS4]

I'd be interested to know Dave what you think of the difference in sound when you have it done. Please let us know.

Ian

[lengster1]

Non res can be too much,valved system is best but pricey,if running de cat its very LOUD,just pre cats gutted wont be so bad,mine resonates around 2k its fine from 1-2k.

[adsgreen]

I don't think by all accounts the res section kills off all the drone - reduces by 30% or so iirc from what has been posted before.

I do know what people mean about the drone and I drive around it and it's not too much of a bother for me.
That being said I've had 105db cars with no soundproofing and the VXR8 had a switched exhaust that I think was 116db on "loud".

[Awd4]

i want more noise but not so much that is drones all the time and is generally just too loud.

I had a non-res valved fitted by MRC and like the increase in volume EXCEPT for the drone between 1000-2200rpm which I found totally unacceptable as I had to completely change my driving style to avoid it. So as soon as this dreadful weather abates I'm off to MRC to have the non-res centre section swapped to a res version.

Have to agree about the drone at low revs, after 5 tanks and 2 weeks since I had a non res, valved Milltek installed, I find the drone quite intrusive, specially when manoeuvring to park - even with the valves closed the drone is a bit too much for me

When you open up though, or when cruising on the motorway the exhaust sound is simply awesome

Overall happy, but it definitely feels and sounds like a different car

[sync24]

EXCEPT for the drone between 1000-2200rpm which I found totally unacceptable as I had to completely change my driving style to avoid it

Dave - I thought that drone was caused by the removal of the 400CEL precats and not to do with the exhaust silencers. However having said that my Vortex system does drone at between 1800 and 2100 RPM and I have twin mid section 'vortex silencers' as well as twin back boxes. Did Doug say that fitting the mid resonated system would cure the drone? I'd be interested to find out.

Also - If there is anyone else running a bespoke system, say from JCWeldFab. It would be good to hear their opinions. I know NeilParf is off to JCWF in a few weeks - perhaps he can report back on drone after his exhaust is made up for him.

Cheers

[PetrolDave]

EXCEPT for the drone between 1000-2200rpm which I found totally unacceptable as I had to completely change my driving style to avoid it

Dave - I thought that drone was caused by the removal of the 400CEL precats and not to do with the exhaust silencers.

Think again, mine still has the pre-cats as it has a cat-back Milltek.

[sar]

EXCEPT for the drone between 1000-2200rpm which I found totally unacceptable as I had to completely change my driving style to avoid it

Dave - I thought that drone was caused by the removal of the 400CEL precats and not to do with the exhaust silencers.

Think again, mine still has the pre-cats as it has a cat-back Milltek.

yep i run no cats in my JHM system but i do have center resonators and its nowhere near as boomy and droney as my old miltek, which was oem downpipes with precats removed, non res, valved.

[sakimano]

Personally my experience has been that catalysts, resonators and mufflers cause drone. Restrictions.
I have ridden in probably fifteen different rs4s (5 in the past 2 months) and about 20 B67 S4s with aftermarket exhausts and that is where I have come up with this.

I have a couple of friends with straight piped V8 Audis and there is virtually no drone. Absurdly loud, but no drone in cabin.

Adding resonators will certainly clean up some of the crackle at rundown and rasp at high rpms , but won't cure drone.

Audi spent a fortune developing our exhaust to eliminate drone. In the end they couldn't do it and tried to abate it a little by closing those extra flaps at low rpms in sport mode. That's literally the only reason they close from 1000 to 3000 in the lower gears.

Still the mufflers have noise and resonance cancelling properties in their design. I have always wondered what would happen if, instead of you guys spending hundreds of pounds to have extra resonators welded in, you instead used the oem mufflers welded in to an aftermarket exhaust. On a 2.75 system I wonder what you would give up in performance. You'd gain back lots of drone elimination, and the flaps too.

Of course on a milltek it's a waste of money because the rest of the milltek is nearly identical to stock and the mufflers are what you paid thousands of dollars for.

[adsgreen]

Take a stock oem rs4 and unplug the exhaust flaps.
I remember when my exhaust flaps failed due to the one way valve.
There wasn't any extra drone.
Also worth pointing out that the low rpm valve control isn't applied for gears 4-6 so you can easily test it.
I know this has been done to death before but I still believe it's for euro drive by noise regulations.

Drone is just the exhaust resonating due to the exhaust shockwaves. It's a function of exhaust length and number of cylinders/rpm.
You can use a resonator that has a tube with Swiss cheese type holes to break up the wave reducing the drone. It doesn't really get rid of if but reduces it to make it undetectable with all the soundproofing.
The alternative is to use chambers that effectively increase the effective length of the exhaust changing the rpm the drone occurs. Do this properly you can move the drone outside the ussuable rev range

[stealthy]

i want more noise but not so much that is drones all the time and is generally just too loud.

I had a non-res valved fitted by MRC and like the increase in volume EXCEPT for the drone between 1000-2200rpm which I found totally unacceptable as I had to completely change my driving style to avoid it. So as soon as this dreadful weather abates I'm off to MRC to have the non-res centre section swapped to a res version.

Hi dave,
I'm interested in a non-res section at the moment to swap for my res pipe on the milltek.
I see ur looking at this so let me know if you want to do a deal? I'm based in South London so maybe a meet up half way at a garage to swap them over?
Let me know ur thoughts.
Cheers

[sakimano]

Take a stock oem rs4 and unplug the exhaust flaps.
I remember when my exhaust flaps failed due to the one way valve.
There wasn't any extra drone.
Also worth pointing out that the low rpm valve control isn't applied for gears 4-6 so you can easily test it.
I know this has been done to death before but I still believe it's for euro drive by noise regulations.

I'm just going by what audi themselves said. Guess they could be lying to cover up meeting noose laws....but why wouldn't they just say "we did it for noise laws". As they explain other things in the study guide being done for emissions laws etc.