Ya mine makes the same sound when the MDS kicks in.

 

I've only heard of two things causing this, MDS engaging and the sound being amplified by the new intake tube, or too much air reentering the engine through the egr valve. I've only ever heard of the egr problem in pre 06 hemi's, and the fix was to get an egr baffle with a smaller hole.

 

The sound being amplified makes a lot of sense. This might be a stupid question but, what's an EGR valve? Is it easy to change?

 

I found the answer to my question. Exhaust gas recovery valve. I hear it's expensive.

 

It doesn't make a difference if it's a Hemi with MDS or a 4.7. When you put the cai on the truck they all spit the air back out (sound like it's turbo charged)as the rpm's lower. I checked with the dodge mechanic and he said they all do it. He said that they have always done it but with the stock intake you just couldn't hear it. I 've got a 4.7l & mine does it too.

 

So what did he say, nothing to worry about?

 

Yeah, don't worry about it. It's perfectly normal.