Two versions of Honda's i-VTEC system can be found on K series engines; variable timing control (VTC) can be found on the intake cam of both versions. The VTEC system on engines like the K20A3 only operate on the intake cam; at low RPM only one intake valve is fully opened, the other opening just slightly to create a swirl effect in the combustion chamber for improved fuel atomization. At high RPM, both intake valves open fully to improve engine breathing. In engines such as the K20A2 found in the Acura RSX Type-S, the VTEC system operates on both the intake and exhaust valves, allowing both to benefit from multiple cam profiles