Tomei Camshaft - PROCAM - Nissan R35 GTR VR38DETT, Intake, 264 / 10.5mm Bulbs you've noticed a curved "bellmouth"

you've noticed a curved "bellmouth" profile at the inlet of each intake runner

made to genuine-or-better quality

The distinctive 5 spoke design quickly became iconic in the Honda tuning world

This is because the ECU controls the increase in fuel and ignition timing retardation to prevent knocking in the combustion chamber due to the rise in water temperature

On the other hand

Tomei Camshaft - PROCAM - Nissan R35 GTR VR38DETT, Intake, 264 / 10.5mm Bulbs you've noticed a curved "bellmouth"When opening the intake valve during high acceleration the G from the camshaft requires to send as much mixture to the cylinder, Intake, the shortest time possible. However if the speed is too high it can damaged the Valves, Valve Seats and Valve Springs if the Acceleration G is too high. The Asymmetrical profile design given to the camshafts will allow the Intake and Exhaust Valves to fulfill the target requirement with the wider duration and high