Airbox whistle

[ChrisC]

Hi All

Anyone come across this?  I am guessing it’s TADTS, but wanted to put it out there just to see.    Car is a standard 360R and I get what I think is an induction whistle or squeal through the standard airbox/filter unit.   It’s only below 2600 in any gear, and only with light to very light throttle openings.  Opening or closing the throttle stops the noise.   I thought it was rear brakes or rear wheel bearings before I realised I could reproduce it at will with the throttle and rpm range, but I have not been able to reproduce it with bonnet off for diagnoses.

Any one else had this with the current air box setup?

Chris.

[Goslima1]

Hi Chris

I have a newly built 420R and have the same issue - its rather annoying !

Going to take it to CC for resolution.

Cheers

Martin

[ChrisC]

Thanks Martin, let me know how you get on.  

[Mucus72]

I have the same issue too, although I quite like this induction noise. 

[ECG1000]

I have the same "quirk" on my 360.
Having just got back from my 1000 mile service at Caterham Donington (where I bombarded Stuart with questions), I'm told it's normal. It's just air whistling past the partially opened butterfly on the throttle body under minor throttle.

Not sure anything can be done to remedy this?

[mike150]

Ditch the air box and fit a cone filter?

[ChrisC]

Thanks all, when I worked out it was induction related I expected it to be a case of TADTS.  I think I am going to change to a k&n panel, but keep the air box for now.  I want to find out what sort of drive by noise it's making before making any significant changes.   I have had a car that was always marginal on induction noise, and that was a real pain in the backside.

[Goslima1]

In my case the noise is not there with the bonnet removed - if it was whistling due to partially opened throttle body why does it disappear ?

Cheers

Martin

 

[SM25T]

Drive above 2600rpm ! :-)

[simon_h]

If it's not there with the bonnet removed then it points to a change there. Does the airbox intake line up properly with the cutout? It may be offset and causing an issue. I have never heard any whistle myself. 

[Goslima1]

It was mentioned in passing at CC that the airbox manufacturing process has been changed and that they had noticed some new 'sounds' but I don't have any further details.

[Goslima1]

I have had some correspondence with CC about the whistle - which they refer to as a 'chirrup'. As mentioned above by others it is 'simply caused by the airflow in the induction system when you open the throttle a certain amount, which effectively causes it to 'whistle'.  It is not a cause for concern'. Earlier cars did not have this as they have an earlier design of plenum which was unsustainable due to manufacturing/QC issues. CC had to be redesign and retool to deliver the current plenum....which has an idiosyncratic whistle. Hope this helps.......sounds like a reason to upgrade to throttle bodies