Compression Ignition (CI) Engines fueled with diesel emits high amount of oxides of nitrogen (NOx) and particulate matter (PM). Exhaust gas recirculation (EGR), Catalytic converter, diesel particulate filter (DFP) are few of the effective techniques to reduce emissions in diesel engine. Now-a-days very emerging techniques are upcoming in tail pipe emissions reductions. However, these are resource of producing Exhaust Gas Backpressure (EBP) on CI engine. The objective of current work is to investigate the performance of diesel engine by employing EBP by controlling gate valve. The tests are conducted at the valve closing of 0%, 25%, 50% and 75% respectively. EBP was measured with pressure gauge. The loads were varied from 0 to full load in step of 25% at constant speed. Also, CFD analysis was done with Fluent 6.2.23 for 50% & 75% valve close. Engine operating parameters (start of injection (SOI), injection opening pressure (IOP), nozzle holes geometry and CR) were maintained at standard operating conditions for diesel engine. The experimental results showed that, For long rote (location) of EBP has no significant effect of EBP. It was noted that only 0.02 kg/cm2 gauge pressure or 1 kg/cm2 absolute pressure was applied. Very less penalty in BTHE and BSFC at most 6% was observed with 50% valve closing. Further, penalty of about 50% in all emissions and more than 16% in performance of 75% valve closing (1.155 kg/ cm2) is inferior and not affordable. It should be noted that for 50% valve closings and 1.05 to 1.08 kg/cm2 emissions were almost closer to 25% valve closing. In addition 3 to 5% penalty of emissions can be observed. In additions, CFD Fluent results of velocity, pressure and temperature- counters, XY Plot and vector have showed significant comparative analysis between optimum pressure 50% valve closing (1.08 kg/cm2) and 75% valve closing (1.155 kg/cm2) at peak power of 3.21 kW. It should be crucial to noted that 50% valve closing (1.05 to 1.08 kg/cm2 EBP) can be applied effectively in tailpipe emissions reducing devices.