If the gas in a stock vehicle was really getting vaporized thus completely burnt, why does the exhaust smell like gas?
Answer: because it is NOT. Even after the catalytic converter deals with the incomplete burn, the exhaust still smells.
So what's going on with the fuel? Is it really burning efficiently?
When the groove is properly applied, the engine exhaust has little to NO smell - similar to how a rocket mass heater exhaust has no smell but, a conventional stove will pollute the neighborhood.
Reason: The modification vaporizes the fuel more because there is more vacuum. The fuel burns much more efficiently in the cylinders. The catalytic converter is now out of a job but, the boss (ECU) says NO, you can't quit slave!
I'll make more work for you, I'll flood you with more gas bastard! This is why getting fuel economy gains is difficult. To get around this issue, people use EFIE's.
However, even if one doesn't get better economy, there's many worthwhile benefits:
No toxic exhaust
smoother running engine
longer lasting oil
better braking due to more vacuum in master cylinder
That is why I dont make modifications on newer engines. You are probably correct with this. I agree more vacuum more turbulence more vaporization more fuel mixing more explosion. I heard some people tinker with ecu or the sensor in the CC being that it is electrically operated they tinker with the voltage.