Strange Whistle Noise Non Turbo

[JG911]

Iv got a 1984 carrera and ever time i put my foot down on the throttle i get a strange but quiet whistle for a few seconds has anyone got any ideas of what it could be

[wcc]

Do you have an aftermarket air intake? Leaks around your air intake regardless would be the first thing I'd check.

[DSPTurtle]

Maybe you have a stealth turbo???

I had a whistling in an intake once after I pulled the silencer and went with a K&N.

[Porschephd]

Intake leak!

[JG911]

Yes iv got the standard air box but with a k&n panel filter in it do you think that would be it

[JG911]

Originally Posted by DSPTurtle

Maybe you have a stealth turbo???

I wish it was play with you 930 lads then

[DSPTurtle]

Easy enough to test... pull the K&N filter out and drive the car around the block. If it goes away then great, if not at least you have taken that question out of the loop.

[JG911]

Yes you all was right with reguards the air leak when i put the filter in i only did the clips up on the front of the airbox and not the back ones but now iv clipped the rear ones up the noise has gone.

Thanks everyone

Just wondering with the panel filter in would it make any difference if i drilled the standard airbox to let more air in

[JG911]

Iv put a standard airfilter back in and the noise has stopped so i think it was the K&N filter making the whistle with the air going in which was also making it backfire not sure if that was a good thing or not

So ill stop with the standard filter for now

[JFairman]

Hard to say, but when putting on a K&N air filter and opening up the air silencer box to flow more air you hear more induction noise.
There are large holes or ports in the the throttle body before and after the the butterfly where the cold start auilliary air valve air hose passages come in.
At small throttle openings just above idle these holes which have sharp edges whistle as air whips over them.
At larger throttle openings you don't hear it as all the air isn't going around the outer edges of the butterfly at high speed right up against those holes.

You won't hear it with the stock air cleaner/housing on there, but you do with the K&N and opened up air silencer housing.
On front engined cars running a cold air intake hose from a K&N filter up to behind the headlights or through the front bulkhead to the grill will silence that whistle from the drivers position.

[NathanUK]

I got induction noise when I fitted my K&N element to my 3.2 carrera too.

[JG911]

Originally Posted by NathanUK

I got induction noise when I fitted my K&N element to my 3.2 carrera too.

Did it course it too back fire out the exhaust ?

[NathanUK]

Haha, now you mention I think maybe it did. If I lift off in 3rd gear sometimes it bangs I don't remember it doing this before the K&N.

[JG911]

Yeh mine did when i had my K&N in iv took it out now.

[NathanUK]

You know, I have often wondered if the K&N has done my AFM any harm. Any ideas anyone?