The rising cost of fuel, emerging stringent emissions norms, superior fuel economy and power output closer to the gasoline fueled engine with clean exhaust gas, it becomes necessary to develop a dedicated compressed natural gas engine. The Bi-fuel mode engine pitfalls are lower output power, high emissions, and also fuel consumption towards higher side. The Bi-fuel mode engine must be operate on lower compression ratio to avoid knocking phenomena. The study is done to convert Bi-fuel mode engine to dedicated CNG engine. In dedicated engine higher compression ratio is used to obtain more output power, lower emissions with superior fuel economy.