Was looking around to find fuel consumption #'s for a comparable engine to ours to evaluate lift pump requirements.

All I could find was a 450HP John Deere marine turbo diesel. This is equivalent to about a 400rwhp Duramax.

The numbers were actually lower than I expected:

21.2 gallons/hour for peak sustained 450HP consumption.
36 gallons/hour "total flow", which is the bypass + 450HP consumption.

Even the smallest lift pumps sold should meet our needs. Certainly a 100g/h pump SHOULD suffice. I guess that leads to the question of why we see pressure drop in Duramaxes with big tunes with lift pumps that should have nearly twice the flow required.

Is it because quick changes in demand require far greater flow?
Is it because of large amounts of restriction in the stock feed system?

Hmmm...

Get the popcorn this is going to be a long thread

I don't doubt that a 50g/hr pump won't cut it. But it sure sounds like it is not the pump that is the problem.

The CP3 Pump becomes the restriction.

I second the fact that there is some restriction in the engine compartment somewhere causing these fuel starvation issues you guys see. You are demanding way too much fuel in a short burst that the bottleneck cannot be overcome. You push fuel as fast as possible from the tank, but there is still a bottleneck somewhere.

I would suggest taking as much of the stock plumbing out of the equation and just see what happens. Take your output from the liftpump at the tank and plumb it directly into the engine inlet line over the driver side head. Wouldn't take much to try the theory.... If it is not the lines, then you know that it is indeed the CP3 or more engine side.

So, are you saying that a lift pump/elimination of the fuel flow bottleneck will decrease fuel consumption? In other words, give us better MPG?

It would allow actually you to flow MORE fuel. This is for those guys that have a twitch to go fast and need more fuel to do so...

Remeber we arnt just sucking fuel to be burnt. ;)

Shouldnt this be in the fuel and air section??? ;)

Shouldnt this be in the fuel and air section??? ;)

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