Russ,

There you go, I learn something every day. Nice write up.

More injection pressure is better in terms of extracting power from Diesel fuel. I can see how minimizing the high pressure fuel rail length by putting the high pressure pump near the injector would be helpful. Ford (Fix or Repair Daily) had a cam driven injection system on their previous PowerStroke V8 Diesels, but I heard less than glowing things about it. Feedback I got was that if you weren't religious about oil changes, the cam fuel pump system would wear prematurely and cause a loss of injection pressure. This in turn would lead to "cackle" at idle and loss of power.

I'd also be curious as to how the VW PD system keeps the pressure constant over the injection period and constant with engine RPM. A cam system pushes the injection pump at a rate that is proportional to engine RPM. This is one of the advantages to the CDI system is that the pump squeezes fuel into a rail which has a fuel pressure regulator installed at the end. The fuel pressure regulator ensures that the design pressure is present in the rail at all times--it just bypasses whatever fuel the engine doesn't use.

I'm also curious as to how VW controls injection timing. The simplest method would be CDI: Since full pressure is available at all times, the millisecond you turn on the injector you have injection.

Wished there was a website showing these parts.

Thanks much,

webcentre (and pentoman), Tell me more about the E320CDI. What type of mileage are you seeing? I've heard 20 - 30% improvement over the gas version. What's the difference in get-up-and-go-ability from the 320D to the 220D. Driving a 190D 2.2 nonturbo 5 speed, I'm not too concerned about drag racing much. But, I think most people here in the U.S. would really prefer the larger engine. Gas and Diesel is pretty cheap here ($1.35 - 1.50/US gal).

Sholin

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What else, '73 MB 280 SEL (Lt Blue)
Daily driver: '84 190D 2.2 5 spd.