In this case, more noise is the byproduct of more flow.
Really though, when it comes down to it, I would not think it would be easy to "feel" 5 HP. Where you would notice the improvement is down low in the RPM band where the extra flow will improve the efficiency adding torque.
On my Wranglers stock engine, 5 speed, 33 inch tires.
- 5 gear was not usable at 1500 RPM -
- K&N added, you could use 5th at 1500, not usable at 1300 RPM.
- Added Gibson exhaust you could use at 1300, not usable at 1100 RPM.
What does that mean, I improved the engines ability to get more air, more fully filling the combustion chamber, ADDING TORQUE, then more fully expelling the exhaust, adding MORE TORQUE.
I could not "feel" the difference and could not tell you if it made a zero to 60 run difference. I am sure it did but only in a 10th of a second or two. In the higher RPM band is where you will always see the best gains, but really, who wants to twist the I5 to 5500 RPM.
An engine is like an air pump, the easier you can make it pull air in, or expel air the more efficient it is, which means more HP and more torque. In the H3 you will notice it under load from towing, and perhaps in 1 to 2 additional MPG.
Please do not confuse my statements with engine management - fuel or spark curves, ect. This is a basic look.
