Flow Tests

Here are some simple formulas you can use to determine what your injectors would flow at different pressures.  To double the flow through a jet or nozzle would take 4 times the pressure:

If you know the flow of a jet or nozzle at a certain pressure, you can figure the flow at a new pressure:


Here are some formulas you can use to determine how much horsepower a particular injector flow rate will support or how big of injectors you need to support your engine's HP number:

BSFC = Brake Specific Fuel Consumption.  Most naturally asperated engines have a BSFC factor of 0.50.  Most Supercharged or Turbocharged engines have a BSFC factor of 0.65. 

Duty Cycle = The maximum sustained "ON-TIME" of the Injector.  The typical maximum injector ON-TIME sustainable in a modern EFI engine is 80%.  For the above formulas, use 0.80 for the duty cycle.


The following airflow tests were performed on the University of Northwestern Ohio's SuperFlow SF600 Flow Bench.  All CFM values are corrected for airflow at 28 inches of water.  Injector flow rates are flowed at 43.5 PSI on an injector flow bench using test fluid with same density as gasoline.


Throttle Bodies

Mass Air Flow Sensors

Other Air Induction Pieces

In-Tank Fuel Pump Flow Rates

92 Buick Ultra 3800 Supercharged High Volume AC Delco EP311

Walbro 307 In-tank (86-92 GM high-performance replacement)

Injector Flow Rates (@ 43.5 psi)

3800 vin C injectors -- 19.0 lb/hr

3800 vin L injectors -- 21.2 lb/hr

3800 SC vin 1 injectors -- 29.0 lb/hr

3800 Series 2 (non SC) Rochester 17103146 injectors -- 21.2 lb/hr

3800 Series 2 (non SC) Bosch 0280150973 injectors -- 21.2 lb/hr

86 Vette RP 5235211 TPI injectors -- 21.6 lb/hr (Bosch design with plastic tip)

87-88 Vette RP 5235302 5.7L TPI injectors -- 21.6 lb/hr (Bosch design with aluminum tip)

85 5.0L RP 5235047 TPI injectors -- 19.3 lb/hr (Bosch design with plastic tip)

97-up? LS1 Bosch 12554271 grey plastic injectors -- 25.2 lb/hr


3rd Party Injector Flow Test Results

2001 GM C/K Truck 6.0L V8 P/N 25317628 (Delphi EV6 short style injector) -- 22.1 lb/hr (2.78 gm/sec)

1996-up 3800 Series II Supercharged (white LS1-style) -- 36 lb/hr



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