In order to make horsepower you need fuel and air. In this tech tip installment from DSPORT Magazine, they take their Project 2012 Nissan GT-R, and add a few parts to help meter air and fuel flow.
In looking at the datalogs, the Cobb AccessPort reported a 97- to 98-percent injector duty cycle. In reality, this equates to the injectors being at 100-percent duty cycle as the injector doesn’t have any time to close when duty cycles exceed 90 percent. Despite running at a 50psi base fuel pressure (that increases the effective flow to 620 cc/min), the factory 570 cc/min injectors simply lack the flow capacity to support over 600 flywheel horsepower at the richer air-fuel ratios required on pump gas.In real life, we want to keep the fuel injectors at about a maximum of about 80% duty cycle. This gives the fuel injectors time to open, and close between cycles. DSPORT had their stock fuel injectors(570cc) altered to flow like 900cc injectors. This should give them plenty of headroom(about 900 hp) for the next batch of upgrades.
In addition to the fuel injectors, they also upgraded the stock fuel pumps. The R35 has a twin fuel pump setup. One pump was tested by RC Engineering to flow 130 lph(liters per hour), and the other 140 lph. Even though this should be enough fuel flow for 700 whp, they upgraded the fuel pumps to twin 195 lph from HKS.
Head over to DSPORT for more information on their Project R35.