stop the boom!

[peter]

recently had a complete system done at longlife,they have done a superb job and could'nt be more helpful,but the system is really boomy at mid range.the system is sport cat into 3" tube with a large centre box and round rear box with twin exit.has anyone had a similar problem and managed to get it sorted?the boys are more than happy to try anything to help but would appreciate some comments.many thanks.

[s2avant95M]

I have an almost identical setup from longlife. Mine is slightly boomy between 2500 - 3000 RPM, but to be honest its not that bad that i would worry about it. I think this is difficult to get away from with a 3" system. They did ask me how i wanted it to sound before they installed it and said somewhere between OEM and sporty. I believe they can pack the silencers more to reduce the volume but you would need to speak to them about it i guess. HTH

[Greg_S]

yeah thats about all they can do, otherwise if you are cruising along just keep the revs out of the boomy area.

Bit of a nightmare if I tow though because it sits there the whole time and your ears are ringing after a couple of hours of it.

[Fat Audi 80]

I heard you the first time!

[Ski]

You got a 3" sports exhaust fitting and wondering why its loud? lol

[stevieyid]

Mine was the same when i first got it but to be honest it does get better after a few hundred miles.

[Ski]

dont they get louder once they wear in?

[peter]

what kind of rear box have you got?mine is round with twin exit but i have seen an oval rear box with single into twin(on this site) wondered if this would make a difference.

[mastermind]

If you reduce the inlet pipe of the rear silencer (from your 3" to maybe 2.75") you will cause the sound wave to distort, cancelling some of the sound. This enables you to still run a free flow silencer but much quieter.

[Jamo]

what kind of rear box have you got?mine is round with twin exit but i have seen an oval rear box with single into twin(on this site) wondered if this would make a difference.

Do you mean you have a jap style back box?

If so no wonder it's noisy!!

[Ross]

Sounds like you've got a very similar setup to mine - you will find it quietens down a little after a while, either that or I'm just used to it now, because it doesn't bother me any more. I think with a 3" performace exhaust there's always gonna be a bit of boom... Cruising speeds of around 50-70 are worst with mine, at 80+ the tone raises enough to not really be noticably loud.

[peter]

longlife replaced my rear box this week,making it longer but this has only made the tone deeper and lower down!i think as someone mentioned earlier the next step is to reduce the bore size of the system from the centre box to the rear,longlife think this may do the trick without affecting flow to much as the gases have cooled down a bit by this point!does anyone know the diameter of the original audi pipework?

[Jamo]

2.5"

But Rotoryboy has done what you want to do 3" down to 2.75" in the rear and it's still fecking loud

[S2 PTH]

After a noisy Clio, I don't really want to make my Coupe louder! Mine was really bad at about 70/75mph (Made worse by the 3" stainless airfilter system under the bonnet!)

On the Audi, the exhaust is rusting a bit on the backbox, and I think I'll wait till It starts blowing till I get a new system, but really don't want to go loud. I supose thats what happens when you fit a relatively cheap (and un-tested) system to your car, it resonates at a particular frequency, which audi engineers would have designed out of the original system!

Does anyone have a system whereby its slightly louder throughout the rev range, but not overpowering at any one point? My Dads just had a pair of silencers taken off his XJS 4.0, and I don't think hes that pleased with the result (Too boomy midrange, not enough fizz at redline). It seems you have to spend alot of money to have a quality sounding system!

[Fat Audi 80]

Milltek, it supposed to be slightly louder than stock and where I will probably go if I need to replace the Exhaust...

Cheers,

Steve.