Airflow Chart


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 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

 

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)�
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 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

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.

 

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