Flow Tests

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.

Air-Flow

Throttle Bodies

• Stock TPI/LT1 48mm Throttle Body w/o airfoil -- 783.0 cfm

• Stock TPI/LT1 48mm Throttle Body w/ airfoil -- 821.9 cfm

• TPI/LT1 52mm Throttle Body w/o airfoil -- 848.9 cfm

• TPI/LT1 52mm Throttle Body w/ airfoil -- 898.8 cfm

• Stock 98 Camaro 3800 II Throttle Body -- 554.3 cfm

• Stock 4.3/5.0/5.7 2bbl TBI complete -- 574.1 cfm (dry)

• Stock 4.3/5.0/5.7 2bbl TBI w/o injectors -- 584.7 cfm

• Stock 3800 vin L throttle body w/ screen -- 419.1 cfm

• Stock 3800 vin L throttle body w/o screen -- 444.8 cfm

• 4bbl MPFI Holley Throttle Body -- 1287.6 cfm

Mass Air Flow Sensors

• Stock TPI Bosch MAF sensor w/ screens -- 517.8 cfm

• Stock TPI Bosch MAF sensor w/o screens -- 658.4 cfm

• Stock 87 GN 3.8L Turbo AC MAF sensor w/ screen -- 584.2 cfm

• Stock 86 2.8L AC 5-wire MAF sensor w/ screen -- 576.2 cfm

• Stock 96-up AC 3100 V6 MAF sensor w/ screen -- 616.4 cfm

• Stock 96-up AC 3100 V6 MAF sensor w/o screen -- 670.7 cfm

• Stock 94-up LT1 MAF Sensor w/o screen -- 719.0 cfm

Other Air Induction Pieces

• Stock 85-87 Firebird TPI airbox mid piece -- 499.3 cfm

• Stock 88-92 Firebird TPI intake bellows w/ integral 90 degree bend -- 693.0 cfm

In-Tank Fuel Pump Flow Rates

92 Buick Ultra 3800 Supercharged High Volume AC Delco EP311

• 36.6 Gallons Per Hour @ 43.5 PSI

• 25.8 Gallons Per Hour @ 60.0 PSI

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

• 255 liters per hour (67.3 gal/hr) @ 70.0 PSI

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 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

Fuel Pump: Delphi FE0114 (interchanges with Delco EP381) - 32.4 gal/hr @ 61psi. = 194.4 lb/hr @ 61 psi (will support up to 299hp on a super or turbocharged engine that has a BSFC of 0.65)

Fuel Pump: Delphi FE0111 (interchanges with Delco EP376) - 27.6 gal/hr @ 50.8 psi = 165.6 lb/hr @ 50.8 psi (will support up to 255hp on a super or turbocharged engine IF you were only running 51 psi of fuel pressure)

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:

• New Pressure = Old Pressure x (new flow / old flow)²

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

• New Flow = Old Flow x √ (new pressure / old pressure)

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

• HP  /  Number of Injectors  x  BSFC  /  Duty Cycle  =  Injector size required

• Injector Size  x  Duty Cycle  /  BSFC  x  Number of Injectors  =  HP supported

• Fuel pump flow rate (lb/hr) / BSFC = HP supported

• 1 gallon of gasoline =  about 6 lbs

BSFC = Brake Specific Fuel Consumption.  Most naturally aspirated 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.

E-mail   |   Return to the Home Page