Quieter 2nd Gen.

[joecool911]

Has there been any advances in injector quietness over the ears for VP pump style injectors? In the same topic, do tuners that adjust timing help with engine noise?

[MnTom]

The only way to quiet the VP trucks to the level of a CR is by turning the key off. What you are hearing is the sudden rise of cylinder pressure due to the injector putting fuel into the cylinder. The CR trucks have 'multi-shot' injections to make the cylinder pressure rise more gradually. As far as timing on a VP pumped (along with the P-pumped and VE pumped) engine the more retarded the timing is the more subdued the sound is and the more advanced it is the more harsh the sound is.

[dripley]

"Turn the key off". Thats a funny one right there. True, but funny. 

[mopartechnician]

2-stroke oil helps a little

[Mopar1973Man]

MPG fooler and/or warm air intakes help too. This tend to retard the timing. IAT temps of 100-140*F will bring the timing down and make them quieter.

 

Tighter valve lash 0.008 on intake and 0.018 on exhaust.

 

Lower cetane fuels. (~40 cetane)

 

2 Cycle Oil (128:1 ratio)

[ISX]

I have a bosch book and it showed a graph of the pressure spike of injection and VP trucks are the most rapid of all.  It explained that the rapid pressure rise and the resulting injection of a ton of fuel made the thing knock very loud.  The P-pump trucks have a slower pressure rise and the CR trucks use a preinjection to soften it.  If the CR didn't use a pre injection, they would be worse than the VP.  

 

There is no real solution since it is just the nature of design.  Now that I think about it, 2 stroke oil probably lowers the cetane a little and gives the injection a smoother ignition since lower cetane doesn't ignite as quick or violently.  High RPM diesels (like in some diesel race cars), use very high cetane because it needs to burn more like gasoline, rather than slowly burn like regular diesel.  

 

My theory anyways.  

[rancherman]

2-stroke oil helps a little

 

X2.   It  does  help  soften the 'blow'  a  bit!

 

Turn the radio UP!

Edited April 16, 2014 by rancherman