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Intake Noise Reduction - XFlow


jonboylaw

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Ok, managed to sort the Silencer to get it quiet enough to hear the carb noise now and boy is it loud !

 

Just a general question to those X-flow-ers out there, do your ears ring after a blat ?? Coz mine most certainly do.

 

Is it normal for intake noise to drown exhaust noise?

 

At about 3500 rpm onwards the intake noise is very loud, with a noise that I can only describe are "cracking" (and not in the "excellent" sense).

 

Is this par for the course or is there anything I can do to quieten down the high frequencies a bit.

 

I am running an 1800 xflow with twin 40 DCOE webbers and standard K&N filters, no trumpets etc....

 

Would changing the filters and adding trumpets quiten down things at high revs (Am thinking better flow may cut down the HF contributions).

 

I really like the sound but it is incredibly loud and my ears are ringing after a blat.

 

😬

 

Jonathan

 

-----------------------------------

1db too loud ! ☹️

Got the Raceco, just need a Gasket fix !

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Trouble is that the local track has 101db limit and I think the intake noise is really close to that.

 

Will be putting the plugs in and smiling at the marshals.

 

I love the sound, so raw, almost primeval, leaves me with as buzz for about an hour after driving.... 😬

 

I guess if I wanted it to sound quiet (soft???) I would have bought a "K" 😬

 

Jon

 

-----------------------------------

1db too loud ?

Got the Raceco, fixed the gasket *thumbup* *thumbup*

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I feel the noise is a safety feature.

 

You are a speck in the blind spot of any car bigger than a nissan micra. Appart from fitting a big flag to you rollbar or a flasing orange light there is not much you can do.

 

But the noise, that rumble it get mistaken for a V8 by those who don't know and think everything without a roof if a cobra. ( it happens alot down here,mainly when filling up. I think the correct frase is " Hey Bru is vat a cobra." )

 

Back to my point.

Sound travels around corners and allow people to hear you and have some sence that there is something they can't see. Often they will look around to see what they are missing. or simply take note that there is someting there.

 

The noise is the best part about this car, Along with the handling, acceleration etc etc.

 

Birkin S3 Installing a Toyota 20v 4AGE motor.

I must, I must, improve my thrust !

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My induction noise definitely seems to drown out the exhaust. And there are also various phases of noise. The one that used to disturb me was the "lightish throttle 60-70mph phase" - the induction turns to a sort of hammering! I've got used to it all now but used to worry about all sorts of diabolical things happening with my internal parts......

 

I feel it's one of the great things about the X-flows that give it character - but it does wear it bit thin if you are going a long way. The ideal thing would be to have 2 Caterhams.

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Ithink that by adding trumpets, you will alter the whole feel of the car, long trumpets are better I believe for top end and short for bottom end. The trumpet must also be 25mm below the outer plate of the filter or less to work properly.

 

 

X/FLOW 1700 DD 1990

ROAD USE ONLY..SO FAR

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Jonathon, I also suffer from loud induction roar, X-Flows, ain't they great ! !,

 

I have fabricated an ali box over the trumpets, (long ones) and the noise is slightly attenuated, this perhaps could be reduced further if I install the air filter in a different position.

 

Whether this would suffice for the man with the sound meter at the side of the track I don't know, but the noise whilst driving is now less, more screaming from the gearbox now.

 

Post back if you want some piccies,

 

Regards Nigel.

 

1982. 5 speed, clamshells. B.R.G / Ali. The True Colours.

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Having been congratulated by the noise police at having the loudest car at castle combe a few yrs back and having to buy a new system from Merlin to pass the test, when i bought my caterham i borrowed my friends noiseometer and discovered that my nice new expensive caterham supplied box emmitted 96db and the webbers 98db! at 4500 rpm.

 

It is still too loud for shmbo and i cannot afford to change it (the wife) so i am working on an intake silencer to remove those nasty mid range decibels by masking the frequency and not the air flow.

 

If i manage it i will post.

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