Intake air flow modification

[kwtorbe]

I plan on testing this theory on my '97 civic HX with a d15z1 intake manifold. I need a VX intake because I want to maintain the EGR valve.

I will port match the head to manifold ports. Then I will either port the TB area out to accept the larger HX throttle body and use HX injectors and sensors (may need to make an adapter which I can do with a drafter friend of mine and his machinist friends), or I will use the smaller VX TB and the smaller VX injectors and sensors (but then I worry about compatibility of the electronics).

Ford 5.0 guys install larger mass air flow sensors, TBs, and fuel injectors for more horsepower; why not install a smaller TB and injectors for better FE?

The theory I am going off of is Q=VA. mass flow=velocity*area. The VX has smaller runners so the same mass of air with move with a higher velocity. I believe this may increase FE, but I know it will increase my torque and HP at lower rpms and decrease my overall horsepower and torque which is found at higher rpms in a 4 cylinder.

From personal porting experience on mopar 318ci heads to the port size of 360ci heads, I know that heads with smaller ports provide better FE and a lower rpm powerband, while ported heads provide better high rpm power but kill low end performance. This is the reason racers use high stall torque converters and steep gears with massively ported heads and large lift camshafts.

If nothing else I believe my d16y5 will have better low rpm power.

Any suggestions on VX throttle body vs. HX throttle body and there abouts are greatly appreciated.