flynbludream

iTrader: (1)

Has anyone done FI on an active fuel management 5.3 setup? Will it still work like a stock running engine? The thought of a high MPG engine at normal throttle and then a 20+PSI capable engine intrigues me. Will this work?

flynbludream

iTrader: (1)

Beuller.... Beuller....

minytrker

iTrader: (13)

I wouldnt trust the DOD lifters for any kind of performance build.

bettonracing

iTrader: (3)

No direct experience w/ DOD + FI but may help shed some light why it's not so popular.

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

427

iTrader: (3)

What does the DOD lifter do when the cylinder is shut down? Does it just not open either valve?
Would be interesting to try this, but you might hit some snags.....

Kurt

slow67

iTrader: (2)

Yeah, it lets the intake and exhaust valves bleed down.

denmah

iTrader: (2)

i was making 475rwhp with a maggie and g8gt setup
and the ****** lifters died, the rest of the guys are right about not pushing performance on DOD lifters

427

iTrader: (3)

The weight of the lifter should be bad, that probably causes some issues. When your lifter broke did it fail at the wheel or did the DOD part break and cause the valve to not open? Do you still have the broken parts?
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

BLINGOLE

iTrader: (5)

Recently at my dealership we had a batch of regular lifters mis-boxed with dod lifters and that was a mess! We had about 10 sets that ended up going in 3 trucks and of course two fo the trucks got 2 bad sets. So just think of the labor/parts cost we had to go threw.

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.

bettonracing

iTrader: (3)

Collapsed lifter = significant slop in valvetrain.
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