West Coast Cummins

[ThaddeusW]

I have has a question burning in my head for about a week. At Macungie there was an Autocar (or was it a Brockway) that had the Cummins with the west coast exhaust manifold. What model of engine was that and was it solely found in west coast trucks? Did any ever find their way into Macks? It had one hell of a unique sound, I wish I made a recording.

[Rob]

I have has a question burning in my head for about a week. At Macungie there was an Autocar (or was it a Brockway) that had the Cummins with the west coast exhaust manifold. What model of engine was that and was it solely found in west coast trucks? Did any ever find their way into Macks? It had one hell of a unique sound, I wish I made a recording.

Was a California thing. It caused the emmited exhaust smoke to be an artificial green; much like the tree huggers out there.

Rob

[b61fred]

I think you are talking about a Cummins rear drop manifold with the fin inside, The sound is different because the firing order of the cummins and the way the exhaust ports are. Basicly the front cylinder fires and then the back. The two exhaust pulses hit the rear of the manifold at the same time and then a slight pause. Kinda has a Jake brake sound to it to me.

Morgan

[ThaddeusW]

I think you are talking about a Cummins rear drop manifold with the fin inside, The sound is different because the firing order of the cummins and the way the exhaust ports are. Basicly the front cylinder fires and then the back. The two exhaust pulses hit the rear of the manifold at the same time and then a slight pause. Kinda has a Jake brake sound to it to me.

Morgan

Yes, that is what I am thinking of. Was it a different engine model all together or just a different manifold? Were they turbo charged? It did sound like a jake brake, that interrupted exhaust note is quite unique.

[b61fred]

Well the true sound maker was the 275 cummins with the super charger, The cam is slightly different in the 275 vs. 290,300,320 hp versions. I think it might be reffered to as a thumper cam. The superchaged engines have no restriction on the exhaust, the turbo engines have the turbo to muffle the sound. The 200,220,and 250's can be fitted with a rear drop, and sound very good, but the King is the supercharger engines. The supercharged engines also have a lower compression ratio than that of thier naturaly asperated brotheren, with the efect of the pressure fed intake makes more bark noise.