The whistle isn't an issue with the spacer. It's there without the spacer as well. If you are selling it because of the whistle you may want to consider.

 

lol i happen to like the whistle but i there is no noticable gain i had one on my early bronco and noticed a huge diff but it wanst injected but hey if you do want one i wouldnt pay full price it seems to be lots of people have them laying around but hey i dont think ive seen to many in the forsale section hmmmmmmmmmmmm makes you wonder huh............

 

AIRAID Sells the TB spacer saying it whistles. Right on the box it says "If it whistles it's working". It's junk, though. Mine whistled when I was on the throttle, more than just the AIRAID alone. I didn't really care but it didn't do anything and I swear my Jeep ran better without the spacer. Now I don't have either, though.

 

I just wanted to make sure that it's understood that most of the CIA's are whistling even without the spacer.

Since these things have been out, I've always been under the impression that they don't improve horsepower but they do improve torque. I've had a few sports cars and the dyno charts on most of those cars w/spacers has shown improvement with a small amount of low end torque but has also shown a small loss in the amount of horsepower. The only thing a spacer really does is allow a small amount of more air into the intake plenum, which is very minimal. But the corkscrewing of the air is a very good idea for upper horsepower, however, most of the spacers have little effect on channeling the incoming air of the Jeep anyway because of the Jeeps lower RPM nature.

That's all I know about these things. I hope it's helpful.

 

Be careful making blanket statements about turbulent boundary layers and BS. Don't forget the lowly golf ball. Its turbulent boundary layer separates later than if it had a laminar boundary layer, thus reducing drag. I seem to remember VW putting vortex generators on a vehicle roof to create a turbulent boundary layer that kept the airflow directed onto the rear spoiler instead of over it.

Also, proper air/fuel mixing is assisted by turbulence, so laminar flow isn't necessarily always desired in an engine. It may help more air flow into the engine, but it needs to mix with fuel at some point.

Disclaimer: The above statements certainly do not endorse "snake oil" automotive add-ons, however. The OEMs have thousands of engineers working to squeeze every bit of energy out of gasoline, at reasonable cost and within EPA emission requirements. If there were "magic bullets," they certainly would jump on them.