11 replies to this topic

[Skortchio]

Coming home tonight from a BBQ I noticed that my mini, Ogy was making a high pitched whistling noise while traveling at speed (around 70).

It's definitely not a squeal but a whistle and only presented over a small rpm range (about 70% throttle), any more or less and it would stop.
It wasn't obtrusive, just odd and I hate random noises.

Anyone else encountered this or similar?

[thebullet]

Me! I put it down to my K&N filter? just a certain amount of acceleration and it would whistle.

[Skortchio]

Oh right, that would make sense that it only started the time I went for a long higher speed drive, without the stereo blasting due to a passenger, that I notice it, right after fitting a K&N cone!

I guessed it was carb ended, suspected something chokey. K&N sounds good though as long as nothing is 'up'

[charie t]

Oh right, that would make sense that it only started the time I went for a long higher speed drive, without the stereo blasting due to a passenger, that I notice it, right after fitting a K&N cone!

I guessed it was carb ended, suspected something chokey. K&N sounds good though as long as nothing is 'up'

I wouldn't go around blissfully unaware. The air filter shouldn't make noises, get it checked out properly

[Skortchio]

If it's the same sound bullet experienced with a K&N cone then it could simply be sympathetic resonance at certain air speeds / throttle opening.

Checking out curious noises is of course best practice, hence first port of call being here to find out similar cases.

[tiger99]

Crudely speaking, the more easily the filter allows air to flow, the less silencing it provides. I think the carburettor whistles at certain conditions of flow rate and piston position, and you hear it because of the reduced silencing. Even fixed jet carburettors have some resonances at certain engine revs.

I really don't think anything is abnormal, unless you have an air leak.

[thebullet]

K&N cone here too. I am about to fit two of the things web I get my twin cabs on.

[stickycreambun]

Everytime I have fitted a air filter that was not the standard airbox I have had some whistling at some certain points through the rev range. How about put the airbox back on and go see if its still there?

[Skortchio]

Hey Sticky,
It only manifest after changing the filter, it's been on a week or so but last night was the only time I've driven at motorway speeds without the stereo up as there was a passenger.

It would seem a fair bet that I'm hitting that 'not so sweet' spot and hearing the whistle. But yeah 5mins to swap the filters and blast up the A13 wil confirm :)

[rickthirteen]

just had a replacement engine - with a K&N fitted - in my mini and noticed a whistle on accelerating, seems to stop furter up the revs or i cant hear it anymore over normal road noise - any one else had this...is it common for Kand N filters to whistle like this..?

[Skortchio]

That's pretty much what mine does, mostly noticible at a certain point in the rev range but with the window open you can hear it while on the gas.
General concensous is that it's just resonance, I've had nothing go bang, pop, or shudder since fitting it and the noise starting. It also went away when I put the normal filter and box back on.

Enjoy the whistle of more induction :)

[rickthirteen]

thanks Boss