Dry Sump Pump performance curves 1

[Ashman2k2]

I am working on a dry sump retrofit project for the VG30DETT engine in a Nissan. I have machined a piece of aluminum to drive the oem oil pump to get an idea of the flow rate vs RPM and head in order to size the dry sump pump accordingly. I will be testing it sometime this week.

I thought that aftermarket dry sump pump performance curves would be readily available for proper sizing of the drive ratio..but I guess I am wrong. I called Moroso inquiring about this, and they say that it is internal information...
Anyone have any recommendations or data on any popular or applicable multi-stage dry sump pumps? Doesn't make sense to me to just run the pump at half engine speed blindly..

 

[tbuelna]

Ashman2k2,

With dry sump scavenge pumps, the scavenge volume flow should be anywhere from 2 to 4 times the pressure pump volume flow.

Gear type pressure pump drive speeds are usually based on a max inlet flow velocity of 6 ft/sec or less to prevent cavitation. Gerotor type pumps use lower inlet flow velocities, since the inlet flow must turn a corner.

You can calculate the flow velocity if you know the inlet port area and the displaced volume per rev of the pump section. Select a pulley ratio that gives you a safe inlet flow velocity at max engine speed.

Here's a gerotor pump reference:

http://www.vianenterprises.com/Sizing.htm

Hope that helps.
Terry

 

[patprimmer]

A real rough way to calculate displacement per revolution of the pump is to fill a section of the rotor between two teeth on the gear with plasticine then see how much water the plasticine displaces, then multiply by the total number of between teeth gaps on both rotors. This will over estimate slightly as it will measure 100% of the volume carried toward the pump outlet, but will not subtract the small volume carried back between the meshed gears or the leakage between the rotors and the housing and end plates.

The leakage on the scavenge side will be lower than the leakage on the pressure side as the pressures are a lot lower, like almost zero.

Regards
Pat
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