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MkV Exhaust resonance ?


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Hi all

For those of you that have resisted going the Miltek route with about 4 miles on the clock grin.gif

Mine at 2.5k miles now seems to have a slight exhaust resonance at about 2-2.5k revs. It's no way really bad but wasn't there before (pretty sure) you can feel it more than hear it and is mildly anyoing hope it clears up as the miles go on

Anyone else on the oem exhaust (or am I the only one left ! grin.gif) noticed this at all. I believe the Mk4 had a similar 'feature'

Cheers 169144-ok.gif

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Urgghhhhh yep, same problem. Milltek amplifies it and remap amplifies it again.

2400rpm is the magic number.

I'm not bright enought to work out how to link to a thread but check out my experiences in Milltek / remap / haldex.

I can assure you that the OEM resonance really is not that bad at all - certainly now I'm back to it.

rs32, Milltek fitted an alternate centre box and rear pipe baffles on mine. Didn't help. I'm reliably informed that it is a DSG specific problem.

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this gets interesting Ian - your situation and my recent noticing of the "feature" on mine seems to suggest that the Milltek cat-back behaves differently if the car is remapped.

I can live with the sound of mine - normally fantastic. After driving it hard for an extended period though I get the severe boominess resonating through the transmission tunnel.

Milltek called me back within 2 hours to offer to take the car in - can't say fairer than that and they were very interested in the fact it's a manual

SA - I rememember saying to you at Castle Combe how good the exhaust upgrade is - this opinion hasn't changed and I will be happy for Milltek to resolve the problems slowly if necessary - like RR I don't work for them but it is a very good quality aftermarket part IMO

Make the dealer aware of the problem with yours SA - and see how it develops between now and 10k - not worth losing the car for time spent in the garage IMHO 169144-ok.gif

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If you think of the exhaust system as a single piece of pipe, it will vibrate at a natural frequency depending upon its length (like a slide whistle changes note when lengthend). When noise (vibration) from the engine occurs at the same (or multiple of) frequency as the exhausts natural (resonant) frequency, the pipe will resonate and cause a low frequency tone to be produced (drone) which causes vibration through the chassis.

The length of the exhaust is usually tuned so that the resonant frequency is outwith the normal rpm range of the car.

Could it be that VW may have miscalculated (or not considered) the length of the system, and miltek followed suit???

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Resonance - an intense sound produced by sympathetic vibration. This exactly describes the effect I was getting, peaking at 2400rpm.

I had the Milltek fitted first, bad, followed by a remap with a full refit of the Milltek a week later, worse. 2400rpm is exactly where the remap put maximum torque (rolling road results)

RS32 - I'm not surprised Milltek called you in, it was their people who informed me that it is DSG related - I don't really believe that.

I half suspect there is a fitting issue here as AMD checked out my whole exhaust system when it went back to OEM and I think it is better than before... mind you I could well have lost some hearing from the experience fekr.gif.

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