Ferrea Dual Valve Spring Kit Nissan 200sx SR20DET.

Price is for Complete set of Ferrea Dual valve spring kit with Titanium retainers and seat locators. OUTER SPRING DIAMETER 23.1mm / 30mm MAX NET LIFT 14mm INNER SPRING DIAMETER 17.2mm / 23.1mm SEAT PRESSURE 80lbs @ 34mm OPEN PRESSURE 195lbs @ 24mm RATE INCH 254 COIL BIND 22mm The new Ferrea Valve Springs are processed with premium-grade alloy and feature special thermal treatment. Ferrea's advanced spring design and material specs have uniform load and stress distribution even in the most extreme racing conditions. Great for high revving applications. These valve springs and retainers will reliably allow your engine to rev high without the worry of part failure, valve float, or coil bind. Aftermarket valve springs are made out of superior metal alloy's and optimized spring rates to make sure your valvetrain can keep up with your cams at high RPM. Whether you are rebuilding your engine, or building an all out race engine, replacing your valvetrain with Ferrea components will allow you to rev higher, and go more aggressive on your cams. Ferrea is the top of the line when it comes to valves springs and retainers. If you google "Ferrea" you would be hard pressed to find anyone say anything bad about them. They are not the cheapest on the market, but if you want the best, Ferrea is the way to go.