K&N air filters create a whining noise?

[Pitts Pilot]

I have just fitted a pair of K&N air filters to my SL350. They were a straight swap for the standard filters.

Apart from hearing more easily the engine change down gears with the auto box there is a high pitched whine, almost like you hear went the wind blows very hard, when I accelerate.

At first I thought it might be the road surface and tyres, but after several miles it’s not.

Any ideas what this whining noise is, it’s quite disconcerting?

Also the exhaust has a tad more 'growl' to it, together with a little more bass.

All I did was change the blinking filters, now the car sounds very different.

Can anyone explain?

Many thanks
Rob

 

[Bobby Dazzler]

Maybe the much referred to "induction noise".

If it sounds different then it's probably OK.

If it sounds disconcerting then it suggests another problem. Are the covers seated correctly?

 

[Pitts Pilot]

I took time to seat the covers, but I think I'll have the filters out and re-seat them again, just to see if that makes a difference.

Thanks for the pointer

Rob

 

[martyz]

Your engine is now breathing more air,and it's normal to hear the difference.
Hows the performance?

 

[John]

You could try the old ones again, see if the noise goes.

Chances are it is the induction noise as suggested.

 

[Sp!ke]

Your engine is now breathing more air,and it's normal to hear the difference.

It won't be breathing more air - it will just be filtering it less.

 

[flango]

If its not induction noise which is normally a roar then it sounds as though you have trapped one of the outer edges of the filter in the housing, saw this on an MG and it was whining its head off

 

[Pitts Pilot]

Maybe the much referred to "induction noise".

If it sounds different then it's probably OK.

If it sounds disconcerting then it suggests another problem. Are the covers seated correctly?

If its not induction noise which is normally a roar then it sounds as though you have trapped one of the outer edges of the filter in the housing, saw this on an MG and it was whining its head off

A very big THANK YOU to evryone, particuarly Bobby D and flango - you guys hit the nail on the head!

I took the air box/es off and sure enough one of the filters was poorly seated and there was a small gap showing that accounted for the 'sounds like a gale whining'.

Have just re-seated the filters and done a test drive, and the whin is gone!

Still not sure whether I like the noticeable increase in exhaust growl/bass, but I live with it for now. I still have the OEM filters at hand.

As for performance, my understanding is that the ECU has to 're-learn' the airflow, so any increase will happen gradually.

Many thanks guys J

Robert

 

[flango]

Glad you sorted it there's nothing worse than unexplained noises

 

[Bobby Dazzler]

Good to hear it's sorted.

This evening I've been bugged by a whining noise too.

I've tried reseating, but it hasn't worked so far.

She just follows me!!