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[Frank Lee]

Originally Posted by cRiPpLe_rOoStEr

Actually I still didn't do such mod, but I am considering to do it into a Volkswagen air-cooled engine. But I have already seen a few "Millerized" engines in leisure boats.

All you have to do is find a cam that says Miller on it and slap it in, right?

[cRiPpLe_rOoStEr]

Just regrinding the cams and increasing the static compression ratio wouldn't make it operate in the Miller cycle, would only make it operate like a Prius engine, emulating the Atkinson effect. The supercharger is also required for the Miller cycle in order to overcome the discompression provided for the longer intake valve timing.

Originally Posted by TruckFan

I've read some about the Miller cycle, but what really makes it more efficient? If you have to use a supercharger to get the same power out of the same engine then it seems that it would be less efficient per cubic inch or cc.

Since the engine operating in the Miller cycle would still have less of the so-called "pumping losses", because its effect makes the power stroke longer than the compression stroke, the engine is, in fact, more efficient.

[Frank Lee]

Oh, I see. So we add supercharging and a different cam and we have a Miller engine. Who hasn't done that?

[cRiPpLe_rOoStEr]

Originally Posted by Frank Lee

Oh, I see. So we add supercharging and a different cam and we have a Miller engine. Who hasn't done that?

Only Mazda and Nissan have done it for automobile engines, but in the 40s and 50s it was more common in marine and stationary engines. I must admit I'd rather get a Diesel swap instead of keeping a V8, but it's still an option...

[Frank Lee]

I thought it was a simple weekend project?

[cRiPpLe_rOoStEr]

Originally Posted by Frank Lee

I thought it was a simple weekend project?

Does it look really so complex?

[Frank Lee]

Have you done it? No.

Have I done it? No.

Has anyone here done it? I doubt it.

Would it be a significant R&D effort to make it work? I think so.

Do you glibly suggest the home mechanic take on projects you yourself wouldn't, haven't, or can't do? All the time.

[cRiPpLe_rOoStEr]

Originally Posted by Frank Lee

Would it be a significant R&D effort to make it work? I think so.

Not so much R&D needed. Street-racers have been regrinding cams for years...

[TruckFan]

Sounds like a diesel swap would be much easier and you'd come out with much better MPGs, more torque, and an engine that will last longer.

[cRiPpLe_rOoStEr]

Originally Posted by TruckFan

Sounds like a diesel swap would be much easier and you'd come out with much better MPGs, more torque, and an engine that will last longer.

Diesel engines are always the best option for a truck, but it would be quite obvious if I were the one advocating for that

After looking at what a modern 4-cyl turbodiesel is capable in a medium-duty truck I could consider a 4HK1 from the NPR or a J05E from the Hino 195 among the best options, but considering availability and emissions classes seems like the 6BT Cummins is the easier to register legally. I would recommend a Powerstroke only for an enemy.