yeah, the whistle comes around 1/3-1/2 throttle. s2 emailed me back today and said this,

So I read through some of those forums and the first two are from 2003 & 2004, which means those were the obsolete batch of manifolds, not the Pro Series, and the last 2 aren’t even about Skunk2 intake manifolds.
Unfortunately it is very difficult to trouble shoot a noise over the phone so my suggestion to you would be to either take the manifold to a professional and have them look at it, or double check all the vacuum lines because that’s what it sounds like to me. We have sold thousands of intake manifolds and have had no complaints about a whistling noise.

I then said this

Yeah, you probably wont hear any complaints due to the fact that people tend to either be quiet about these sorts of things or they live with it. From what I have gathered from a post I posted here, https://www.tamparacing.com/forums/h...whistling.html , people for some reason like the sound, they say it sounds like a blow off valve. I would just like to know if you all could test one or two out and find out where the whistle is coming from because would it not only make me happy, but it would probably make you all a little profit due to the ability to say "improved intake manifold; whistle free". Not only do I see your wholesale sales rising due to it, but bringing something up like this to your boss or something could throw you a few bills as well. The way these things sell and with the new competition from Edelbrock, fixing this problem will give you an upper hand. Or you all could not admit that there is a problem and when people like me come around, we can go and buy brand x that doesn't whistle and make our car look like a rice box. I know for sure the vacuum lines are all good and connected, they are all brand new. All seals are good and everything. The sound is coming from inside the plenum somewhere or the runners; I am not quite sure. But I would at least bring it up to your higher ups because I am sure they are all about business growth, no matter how they get there. Believe me, I am no retard and by the way the economy looks, I am sure your company is looking to get ahead. - Nick

Yeah, we'll see what they do about it. lol

 

It's not a bad thing. With a little practice on your throttle foot, you actually can play some tunes. Here is a link to recording I made of my s2 intake
http://www.fishyphotos.com/skunk2-whistle.mp3

 

^ Lmao

 

lol, nice. but no, the more unwanted noise my car makes, the madder I get!

 

lol, nice. but no, the more unwanted noise my car makes, the madder I get!

TRUE TO THAT!!!...mine makes more of a louder sucking sound because of the larger runners but I really don't get a whistling sound...my damn exhaust however is quite annoying around 3k rpm +/- 300 rpm which may overcome the sound from the manifold.

 

when i put the S2K tb on my H motor it wistled with smaller piping, when i went to 3" piping the whistle pretty much stopped

so...man up on your intake piping

 

The whistling is created by one of the runners flowing more or less than the other runners around it. You can also get whistling from a poorly ported head where the flow from cylinder to cylinder isn't close to being equal. Unless you want to rework the manifold on a flow bench you will have to live with the whistle.

 

you think that is where it is coming from? it makes sense but if my head is stock and untouched, then the manifold is where the problem lies?

 

Yes it is the manifold. The skunk2 is known for this.

 

It's not only a Skunk2 that does this, I have experience of an Edelbrock doing the same. It's not a problem, just a rush of air, you could always use a different intake (Read: tube) setup and eliminate it.