Resonance at 80mph

Post by **Iain** » Tue Apr 27, 2004 3:05 pm

I am getting what can only be described as a low frequency resonance at 80mph in 6th. Similar sound to when rear window is open at speed. Goes away at 100mph or I turn the stereo up!

More annoying than anything else.

Any ideas?

Post by **Jon** » Tue Apr 27, 2004 3:29 pm

I had something like that on my first rs4, turnout to be a bent propshaft (which bust the diff) hope this helps

Post by **Iain** » Tue Apr 27, 2004 3:49 pm

Thnx Jon, though only just started in last 1500 miles or so; car has only ever been up and down M'ways and A roads. Never kerbed etc etc. Cant think how I might have bent propshaft? - any easy way to tell apart from pulling car apart?

Only happens in 6th gear, no other gear at same revs or speed?

Post by **Jon** » Tue Apr 27, 2004 8:19 pm

It's not the prop shaft the. It would resonate at a given speed, not revs, in any gear. Sorry

Post by **PhilT** » Tue Apr 27, 2004 8:24 pm

Similar sound to when rear window is open at speed

Is the rear window open? Sorry had to ask

Post by **SPS** » Tue Apr 27, 2004 9:57 pm

I had a similar problem. When I changed the airfilter to a K&N unit I got rid of that problem. The engine also runs much better at lower rews and the respons is much better than before.
My RS4 has complete exhaust system with race cats. I have a MTM program (copy). I run a complete H&R adjustable suspension kit including roll bars. (Stiff but I love it!)

Post by **Iain** » Tue Apr 27, 2004 10:17 pm

Phil,

LOL!!!!

Its just weird that car has just started making noise. Jeeesus, I have resonance and the silence of the bloody lambs under the rear wheel arches......where is Clarice!!!!

Wouldnt change her though........

Trying to understand SPS how K&N will help problem as resonance seems to be coming from back of car!!! Had similar noise on wifes touareg (aka combine harvester) but that turned out to be roof bars on the wrong way around.

Ah well, just have to sit on the m'way at a tonne plus!!!

On another note at a tonne plus, on the M'way, why does Mr Menopausal / flat cap in his MG Rover ZT think he is driving an F1 car and NEVER move out of the way, a mesh grill after all does mean a racing pedigree!!!.....answers on a postacrd.......

Post by **SPS** » Tue Apr 27, 2004 10:34 pm

Sorry if my english language isn´t good enough. The resonance problem I had sounded like it came from rear. Like the exhaust system. It dissapered when I changed to the new air filter insert. It is worth trying if you not have a serious mechanical problem. It is sometimes difficult to understand what you talking about for swede.
My wife has a Touareg V8 but fortunately she hasn´t got any roof bars.

Post by **Iain** » Tue Apr 27, 2004 11:04 pm

SPS,

Thnx. I will try a K&N as I used to use them on my previous cars. K&N are located 2 miles from where I live.

In my ideal world, I always wanted a swedish wife.........who used to be a gymnast!!! Instead, I ended up with an English wife who takes teeth out for a living!!! hmmmmm

What do u think of your toe-rag?

Roof bars since I have owned the car have only been used once......for carrying a Xmas tree!!!! dont imagine they will be used for anything else apart from carrying another Xmas tree this year!!!

Post by **Bushy** » Wed Apr 28, 2004 4:59 am

Not something as obvious as a buckled or out of balanced wheel, has been know, or a loose deflector to the rear brakes

Have you looked under the rear of the car for any obvious loose pipe work, or have you picked up an old plastic bag on the exhaust

Not sure just trying a few options

Bushy

Post by **Iain** » Wed Apr 28, 2004 8:34 am

I have caught the exhaust a number of times on speed humps; car is so low, perhaps something is loose underneath. I'll have someone take a look.

Thnx Bushy

Post by **Nige_RS4** » Wed Apr 28, 2004 9:02 am

Iain, think carefully about installing the K&N - the MAF's on S4's & RS4's can get contaminated by oil from the filter - this can lead to lean running and possibly turbo failure if left - usually without any ECL warning lights

Post by **Iain** » Wed Apr 28, 2004 9:16 am

turbo failure.....$$$$$$$$

Cheers N.

Post by **Iain** » Wed Apr 28, 2004 5:05 pm

A visit to Kwik Fit to look underneath the car showed nothing loose.

Checked balancing on wheels all ok.

Went to Hartwell Audi and mentioned the problem. Didnt have a clue.....they did suggest a 4 wheel alignment though at nearly £500!!!!! I always thought Dick Turpin wore a mask not Audi overalls!!

I havent got a clue? Neither have they!

What next? could it be the exhaust?? Car has only covered 8kmiles though ! always garaged!

Any further suggestions?

Thnx Guys.

Post by **DaveP** » Wed Apr 28, 2004 6:59 pm

Loose spoiler perhaps???

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Resonance at 80mph

Resonance at 80mph

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