The engines all sound different, cr being the quietest, then ve, then p-7100, then vp-44. I think the exhaust tone of a 24 valve sounds the best though. AND LOUDER! Can't beat em.

 

I believe a lot of this is subjective, but injection pressure, style of combustion chamber and timing variances play a large role in the engine sound. Box-stock vs. box-stock, the VP-44 equipped 24 valve engine wins the maximum audible sound contest. The single-shot, high pressure injection shot combined with the signature 24 valve style tumble chamber pistons make these the loudest beasts! If the common-rail engines took away all of them pilot shots and did it with one single blast, this would be a healthy step up again with noise output.. VP44s use approx 18,000 psi, the CP3 on the common-rails are pushing 26,000 psi to inject the fuel. P-7100s are in the 12,000 range, and VEs are less yet! Obviously, injection pressure works with emissions output as well.. but that is another discussion. Ever heard a common rail engine with failing injector(s), they make quite the clatter!

All 12 valves with their swirl-style pistons have a more subtle sound output, but jack the timing on a p pump north of 25 degrees and they start to sound pretty wicked on the revs! Let the timing slip below the 12.5 degree OEM threshold and they start sounding rather mellow and lame. My '96 has marine pistons (tumble chamber) and has quite a unique sound.

The above video with the rapping VP-44 monster pump, I'm not sure i would spend money on one of them pumps when we see smooth running SO VP-44 getting into the 700 horse range.. But i prefer the sleeper look appearance and think a high performance diesel should run nice and smooth, like a wolf in sheep's clothing. The common rail engines pushing 700-800-900 hp run as smooth as any of them..

Exhaust tone?? I always thought the first gens had the deepest tone as well.. but i always attributed that to the larger hot side on the turbo; 18.5 or 21 cm housing vs. 12 cm found on the 2nd gen trucks.. 12 sounds more raspy.

 

I think 24 valves are the loudest and sound the best, they just have that deep sound if they are straight piped that i like and i can tell if its a 24 or 12 from miles away.

12 valves sound good but aren't as loud.

CRs just sound like a wob wob all the time to me, just like a constant deep drone, but i like the sounds of them too.