Brian Crower Mitsubishi 4G63 Eclipse/Evo Single Spring & Titanium Retainer Kit

Brian Crower Single Spring & Titanium Retainer Kit — Mitsubishi 4G63 (BC0100)

A system-matched spring and retainer package for the 4G63, designed to work in unison for better valve control at extended RPM and to support greater lift camshafts.

The retainers are where the gain is. BC titanium retainers are CNC machined from 6AL4V round bar titanium to exacting tolerances and weigh roughly 40% less than the factory steel units. Less reciprocating mass at the top of the valvetrain means the spring has less to control, which raises the RPM where things go unstable.

Springs are designed by PAC Racing for high RPM, wound from the highest grade super clean chrome silicone alloy with proprietary processing for consistent pressures. Quality springs prevent premature valve float, and float is what puts a valve into a piston.

Spring specs: 1.879" free length, 84 lbs at 1.550" seat, 235 lbs at 1.000" open, 0.935" coil bind. Uses the OEM spring seat. Net cam lift capability 0.520" / 13.2mm. Retainer part number BC2100.

Fitment: Mitsubishi 4G63 — 1992-2006 Evolution I-IX, 1990-1999 Eclipse GST/GSX, 1990-1998 Talon TSi, 1990-1994 Laser RS, 1991-1992 Galant VR4.

Includes 16 single springs and 16 titanium retainers — a full head's worth.

This is the kit that unlocks aggressive cams. Higher lift and duration profiles will coil bind or float on OEM springs, and 0.520" net lift is the ceiling this package supports.

Do it while the head is off. Springs and retainers are a head-apart job, so if you're already in for cams or a valve job, that's the time.

Steel retainer version available as BC0100S if you'd rather not spend on titanium.