PowerPages: Honda B16 Engine

Dyno 4: S2-hrd Pro series cnc head

Pros
Many engine builders and tuners favor CNC porting. The advantage is it delivers perfect-sized ports with every cylinder.

Cons
There's not much to complain about. We were initially concerned by the ripple marks the CNC (5-axis HAAS) leaves on the ports. Dave Hsu of Skunk2 tested both a CNC head with ripples and one with smoothed ports on a flow bench. Both yielded similar results, so the ripples don't affect performance.

Notes
Using the Hondata, we tuned the CNC head. We noted a 12.6 A/F ratio at 4200 rpm. We gained 14 hp over the factory head between 7700 and 7800 rpm. Torque numbers peaked 181 lb-ft between 5700 and 6000 rpm. The engine spun freely to 8500 rpm without a hitch.

Tools
12-point, 13mm socket; 10-, 12-, 14-, 17- and 19mm sockets; ratchet; torque wrench; timing gun; valve lash tool

Parts
CNC ported head, double valve springs, stainless valves and titanium retainer

Installation time
20 minutes

Temperature
Air temperature at 80 degrees Fahrenheit
Temperature difference from previous run: -2 degrees Fahrenheit

2000 to 3500 HP range: 0 to 2
3500 to 5500 HP range: 2 to 6
5500 to red line HP range: 6 to 14

2000 to 3500 TQ range: 0 to 3
3500 to 5500 TQ range: 3 to 7
5500 to red line TQ range: 7 to 14

Peak HP: 258
Peak TQ: 181

By Richard Fong

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