MitsuStyle - View Single Post - Uber modified stock evo intake manifold vs DI SMIM

**Shane@DBPerformance** · 06-20-2008

Duty cycle determines when you run out of injector. Duty cycle is effected by both pulse width and RPM. Torque, pulse width and VE follow the same curve. Duty cycle does not. With higher RPMs, there is less time for an injector to be spraying, so it maxes out easier.

At 5000RPMs 16ms of pulse width might be around 65% duty cycle, but at 8500RPMs only 14ms of pulse width is 100% duty cycle. For example a 300whp B16 turbo Honda that makes peak power at 8200 RPMs will need more injector than a 300whp fwd DSM that makes peak power at 6500RPMs, but more torque than the Honda. A set of 450cc might be good to 300hp on most DSMs, but only good to 275hp on high reving Hondas.

06-20-2008	#20
Shane@DBPerformance formerly ecoli Join Date: Oct 2003 Location: On the dyno Posts: 4,892	Re: Uber modified stock evo intake manifold vs DI SMIM Duty cycle determines when you run out of injector. Duty cycle is effected by both pulse width and RPM. Torque, pulse width and VE follow the same curve. Duty cycle does not. With higher RPMs, there is less time for an injector to be spraying, so it maxes out easier. At 5000RPMs 16ms of pulse width might be around 65% duty cycle, but at 8500RPMs only 14ms of pulse width is 100% duty cycle. For example a 300whp B16 turbo Honda that makes peak power at 8200 RPMs will need more injector than a 300whp fwd DSM that makes peak power at 6500RPMs, but more torque than the Honda. A set of 450cc might be good to 300hp on most DSMs, but only good to 275hp on high reving Hondas. __________________ www.dbptuning.com