Log Splitter Mods: Combining a GX390 with a 28 GPM Pump

Log Splitter Mods: Combining a GX390 with a 28 GPM Pump
May 9, 2024

This video is the fourth in a series in which we're modifying a RuggedMade 300-Series log splitter in search of a 5-second cycle time. So far, we have:

We achieved our 5-second goal, and now it's time to see how changing the engine affects the cycle time.

How Does Hydraulic Pump Size Affect Cycle Time?

The hydraulic pump's size sets the volume of fluid flow in gallons per minute (GPM). A 28 GPM pump displaces more volume than a 22 GPM pump, providing more force, and it should result in a faster cycle time. However, if the size of the pump and the size of the engine are mismatched, it could result in damage to the hydraulic system. Upgrading to a larger pump typically means upgrading to a larger engine.

In this test, changing the engine size from 420cc to 390cc did not make a huge difference in cycle time or bog down the engine, so we decided to run a second test with the smaller engine and a smaller pump to see how that changed the cycle time. As expected, the smaller pump produced less force, slowing it by about half a second

Modifications We"ve Made So Far

  • Engine: We initially replaced the standard 212cc (6.5hp) engine with a 420cc (15hp) engine. For this video, we downsized from the 420cc engine to a 390cc engine.
  • Hydraulic Pump: We replaced the standard 13 GPM pump with a 28 GPM pump, and to further test the 390cc engine for this video, we replaced that 28 GPM pump with a 22 GPM pump.
  • Hydraulic Hoses: We made sure the sizes of the fittings and the hoses matched the 28 GPM pump.
  • Cylinder Rod: We upgraded from a 2.25" rod outer diameter to a 3" rod OD.
  • Tank: We switched from an 8-gallon tank to a 12-gallon tank.