Will active fuel management work on an FI setup?
Most people opt for the peace of mind with the solid lifters. The limit You run up against w/ the DOD lifters is the maximum spring rate you can use. The spring rate directly opposes the [force created by the] hydraulic pressure in the collapsible lifter.
Higher spring rates are generally recommended when adding boost (the manifold pressure tries to open the valve, the spring keeps it shut). Running a low spring rate reduces the amount of manifold pressure (aka boost) you can run - indirectly affecting power output.
You could probably still convince yourself that
- a collapsed (failed) lifter usually means the valve stays closed (somewhat of a "fail-safe"), although history dictates a stuck lifter usually means metal shavings in the oil pan...
- a higher pressure pump to help increase the likelihood that the lifter will stay up, and pop up after intentionally collapsing,
- manifold pressure will actually help ease the load off the lifter moving the valve off the seat, although once the valve is off the seat it only gets harder and harder to push it down further...
- etc
...but considering guys with stock engines are seeing DOD lifter failures I personally would go for the peace of mind with the solid lifters for forced induction.
Throw a small turbo on some solid lifters (say ~67mm), a long gear ratio (<3:1), tell your tuner you want gas mileage (he'll laugh and shake his head while mumbling something about noobs), and You'll be closer to Your goals. And use your cruise control when you hit the highway.
Regards,
Kurt Betton
Would be interesting to try this, but you might hit some snags.....
Kurt
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It seems like they would just shut down the intake valve, but maybe the ex flows backwards if the cylinders coasting. Boosted lifters are normally damaged on the ex side. Neat idea.....
Kurt
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The dod lifters have alot bigger oil hole to bleed the oil down in the lifter to shut the valves down. Also with that the dod enignes all have high oil volume pumps to speed up the process. So if you put regular lifters in it your engine your going to have 100psi plus oil pressure at idle while cold.
Now with highreving performance enignes the dod lifters wont hold lift like a regular lifter due to the larger pintle holes. Which in returns distroys the internals and cam lobes. This is the understanding i have from what ive seen.
Slop in valvetrain = cam lobe beating on lifter (and pushrod).
Cam lobe beating on lifter = metal shavings in the oil pan (and/or broken cam if you get it just right...)
Regards,
The Other Kurt








