Sports Contra Spring V.2 +1500rpm The current version of the counter pressure spring uses a modified alloy spring, providing better elasticity and above average strength. Changing the spring is necessary when tuning engines, the idea is to prevent the initial response of the CVT, so increasing the engine speed, increasing the power with delayed engagement will increase the power when starting from a standstill. The marking on the spring will help you determine the strength of the spring, for example, a spring marked 1500 RPM will delay the response by 1500 RPM. A spring with a higher RPM will give you more power.