id double check everything just to make sure its ok.

 

when the throttle is only partialy engaged, the butterfly is only partialy opened. that is probably why the whistle goes away with more throttle, the air isnt rushing through a smaller opening like it is with partial throttle. blow across the top of a 20oz bottle and listen. then do the same thing to a vitamin water bottle.

 

very nice way of putting that.
I just wanted to make sure everything was normal; i've never heard of intakes whistling, i've always considered it more of a growl, but i gave the local mustang tuner shop a call and they also said it was normal.

 

yea but at 100 mph, it shouldnt be whistling to where you can hear it. unless you just happend to do a bad install job, no offense.

 

There's a rubber gasket that surrounds the opening of the intake manifold. You may want to unbolt the plenum and make sure it isn't rolled over or crimped.

 

i inspected the gasket on the plenumbefore i put the plenum on. I can't hear the whistle at 100, really i cant even hear it at full throttle, the factory exhaust drowns it out, but a guy that owns a shop and that is into mustangs came over this morning, and he said that the whistling is normal, and that it'll get even louder when i get my throttle body and intake[:@]im sure the flows will drown the whistle out soon enough[8D]

 

you heard a crack and its a whistle not a woosh, you may have cracked something that is not normal... check your intake around where the bolts are, a whistle is not normal it should sound like a woosh not a tea kettle somethings off somewhere...

 

if i cracked the intake where the bolts are, there would be a whistle at IDLE AND full throttle, this only happens at 1/4 throttle or so.

 

i'm not sure but you said that you heard a crack and i'd bet that the plasticintake would crack before the alum. plenum.. i have installed a C&L plenum and i have never heard a whistling other than my supercharger & i had the plenum long before i supercharged. good luck!!

 

I just put my stock piece in..no whistle. then i put my friends BBK piece in..no whistle..trickflow..Whiiiistle!!
the trickflow piece has jagged up edges and stuff, nearly cut me, real real poor cut. I will never buy another trickflow product again. I'm returning this POS, and buying an Accufab product