Stage X Group N Twin Scroll Baffled Oil Sump Pan

Track days and the search for ever higher power figures have exposed some serious shortcomings in the standard Impreza sump. The sump collects and stores the engine oil before it is distributed around the engine to lubricate and cool it. On track, hard cornering quickly causes oil surge: lateral forces push the oil to one side of the sump. Because the Impreza's oil pick-up pipe sits in the centre, it can be starved of oil under these conditions. The engine then loses oil pressure, which puts extreme load on the bottom-end components and often ends in major engine failure.

This baffled sump is a modified version of the standard sump pan that counters oil surge with a specially constructed insert (baffle) fixed inside it. By restricting the lateral movement of oil, the insert greatly improves the sump's ability to keep oil around the pick-up pipe, even under extreme cornering. The top deck of the baffle has four one-way valves that let returning oil pass into the sump but stop it flowing back out as it moves around. The baffle also helps reduce unwanted pooling of oil in the cylinder heads, which can happen under high cornering loads because of the flat boxer layout.

It starts as a genuine Subaru oil pan to ensure perfect fitment. Much of the relatively ineffective standard internal shelving is removed, and the pan is re-manufactured to accept the removable Group N aluminium baffle insert. The insert has 4 heat- and oil-resistant nitrile one-way valve flaps that keep the oil where it needs to be during hard cornering on track or in competition.

• Additional -8 boss for a return-to-sump hose from an oil catch tank system
• 14 × genuine Subaru sump bolts
• Stage X magnetic sump plug, pre-lock-wired
• Full installation instructions