What makes the Common rails sound so high pitch and raspy i kind of dont like it.

 

my guess is it has something to do with the efficiency of the motor compared to a 12/24v..

i assume ur talking about exhaust tone, right?

i dont think my truck sounds high pitched at all, but it does rap off real hard on the rollers

 

The way it's injected maybe?

 

yeah maybe

 

valves? air flow?

 

I don't think I have ever heard of a Cummins being called high pitch sounding. I guess compared to the 12V it does. I guess that would bring it down to the injection system and the higher pressure system.

 

Number of injection events up to 3 on the newer ones vs one big squirt on the older iron and exhaust manifold setup doesn't help either.

 

Yea, I swapped my exhaust manifold for a 2nd gen manifold....problem solved.

 

I was always told that the manifold and the way the cam is ground for emissions is the reason for the sound they make. To me they make more of a droning noise than high pitched.

 

Yes you are right...manifold, small turbine housing (back pressure), injection timing, cam etc... basically all the EGR attempts that they made to satisfy the tree huggin hippies is all due in part to the crappy sound.