Fuel Injector Flow Rates
Last Updated: 02-03-03

When tuning an engine, (especially turbos) it might be necessary to change the injectors. However, if unsure about whether they need uprating or not then we can find out the required flow rate using a formula:

Injector Flow Rate (lb/hr)	=	Engine HPx BSFC
		Number of Injectors x 0.8

Where:

Estimated at 3bar fuel pressure.

cc per minute = lb/hr figure x 10.2

HP = cc per minute / 5 (BHP per injector)

HP = lbs per hour x 2.04

example:

For a GTE 16v: hp = 155
BSFC = 0.5
Number of Injectors = 4


= 24.22 lb/hr
24.22 lb/hr x 10.2 = 247.031cc/min.

Power per injector @ Max Flow (100%) duty = 247.031/5 x 4(no. injectors) = 197.6bhp But, they should be run around 80% duty, because if the fuel spray from the injector reaches near the speed of sound then leads to a poor spray pattern

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