Thorny

iTrader: (14)

Earlier this week I was searching for a suspected vacuum leak that I couldn't ever find. I could hear hissing under the hood, but it was faint and I couldn't locate it. Today I greased my idler pulleys which made things quiet enough that I could hear it better. It turns out it is coming from the TB at the hole in the blade. I've had a port and polish done already, but is there anything I can do about that whistle? I know it's coming from that hole, all the noise stops when I put my finger over it, (and not because the engine dies smartass :p)

I don't have a cam yet, but will this winter. Is drilling it out a little an option to quiet it down? I've got a tune scheduled in 2 weeks, so they could tweak the idle then. Right now it's pretty annoying, especially when I turn the engine off and it keeps whistling for a couple seconds.

Black Z/28

I had a similar problem with my BBK, although not the hole. The whistling was cause by air rushing over a sharp edge (in my case the gasket extended a little into the neck of the manifold opening). I cut away the gasket until it was smooth and flush all the way around the neck. I would try to sand down the edges of the drill hole- both sides- create a smooth transition edge (do not enlarge it though). This should help a little (or maybe a lot).

Starion

iTrader: (5)

I had mine ported and polished recently and I can tell it makes more of a whistle sound now when I rev the engine. Nothing real noticeable unless you rev it a little with the hood open. No whistling at idle though. I wouldn't think the porting would be modifying that hole at all but maybe I'm wrong.

I'm assuming that you're removing the entire airbox assembly and maf to isolate the noise while running the motor? damn!

I wouldn't drill it out that's for sure. You might want to ask whoever did your porting what they would recommend if the sound is bothering you.

Thorny

iTrader: (14)

I only notice mine at idle, but I don't think the port had anything to do with it. Bo did it and did a very fine job, I just never noticed it before because of the idler being so loud. It's more noticeable when killing the motor, because it keeps sucking for a sec after everyting else is quiet.

I did turn of the motor before removing the bellows btw

Bo White

iTrader: (59)

You can take the TB off and get a large drill bit and chamfer the hole on both sides and that will smooth out the air flow some. You can do it by hand, dont even need a drill- all your doing is takin the edge off the corners of the hole.