RalliSpec LogoRalliSpec Group N Car at LSPR
> home / catalog / engine internal / camshaft / gsc cams mitsubishi evo 9

Camshaft Set EVO 4G63 MIVEC

GSC's cams are fully machined from forged billets cores on advanced CNC machining equipment.

S1 cams improve turbo spool and provide power gains across the entire rpm range (3000-8000rpm useable range) without any loss in low end. Standard valve springs can be used. Suitable for up to 450whp. .

S2 cams work well with larger turbos with useable rev range of 4000-9000rpm on 2.0L or 3000-8000rpm on stroker setup. Suitable for up to 700whp. Uprated valve springs suggested unless running stock boost and stock rev limit.

S3 cams are for applications over 700whp with extreme modifications and very large turbo. Uprated valve springs are essential.

R2 cams are a high lift version of the S2 cams specifically for improving cylinder filling with large displacement stroker engines. Gains of 25 to 30whp over the S2 cams are possible on a stroker application. GSC beehive spring and retainer kits are required (other options may not provide sufficient retainer to stem seal clearance). GSC5041 spring kit over 40psi of boost while GSC5040 kit will handle up to 32psi.

Backordered 2 to 3 weeks.

Manufacturer: GSC Power Division

Applications:

  • Mitsubishi EVO 9

What do the terms "duration" and "lift" mean with regards to a camshaft? Cam duration is a measure of the amount of time, in degrees of crankshaft rotation, that the cam opens the valves. Generally this is measured from some nominal valve lift. Cam lift is a measure of the height of the cam lobe, or basically how high the cam will lift the valve (minus any valve clearance) or the rocker (in the case of a rocker actuated valve).

How do I select a camshaft? Increasing the cam duration will generally increase peak power while shifting its occurrence to a higher rpm and narrowing the useable power band. The design of the intake, exhaust, and cylinder heads should be taken into consideration when selecting a cam because the best results will be obtained when these components are optimized around a similar rpm range. With a turbocharged application, the cam's power characteristics should reinforce the characteristics of the turbo. For example, a very large turbo that comes on boost at a fairly high rpm should be used with a longer duration cam while a small turbo which has a fast boost response but is inefficient at high rpms is best matched to a shorter duration cam.

What is "overlap"? Overlap is the period of time during which both the intake and exhaust valves are open. At higher rpms the overlap period can be extended to use the exhaust energy to assist in drawing the intake charge into the cylinder while available filling time is decreasing. However, at lower rpms some portion of the intake charge (including unburned fuel) may be lost out the exhaust valve or exhaust flow reversion may occur allowing exhaust gases to flow back into the cylinder displacing some of the intake charge and losing power.

When do I need to upgrade valve springs? High lift cams and increased engine revs will normally require a stiffer valve spring to ensure valve motion follows that of the cam. A valve spring change may also be required in order to shift severe valve spring harmonics outside of the primary rpm range. Valve spring harmonics can result in a loss of spring pressure at critical times. Most mild street cams can be used with stock valve springs but each application is different. When in doubt follow the cam manufacturer recommendations.

What is "degreeing in the cam" and do I need to do it? Degreeing the cam means setting the cam timing to the match the specifications of the cam manufacturer. Milling the cylinder head or block deck as well as manufacturing variations can result in cam timing errors. While it is a good idea to check the cam timing using a degree wheel, actually correcting any errors can be difficult without adjustable cam gears. Moving the cam sprocket one tooth on the timing belt may allow for correction of major errors but errors smaller than 1 timing belt tooth would require modifying the sprocket keyway or dowel.