Performance Calculators

Performance calculators for drag racing, engine, gearing, fuel usage, and more for your Modded Mustang. Just click on the links below to jump to your desired calculator.


Performance calculators - Modded Mustangs



Horsepower Related

Quarter Mile Related

Tire Size Related



Estimate RWHP from Weight and Trap Speed

Vehicle
Weight (lbs)		 1/4 Mile
Trap MPH
Your Estimated
Horsepower


Finding Horsepower From RPM

Torque (ft-lbs) RPM HP

 

 

 

 

 

 

 

 

Finding ET & MPH from Weight & Horsepower

Vehicle Weight (lbs) Horsepower Estimated E.T Trap Speed

Adjusting ET for Elevation

Old ET (s) Elevation (ft) New ET

 

 

 

 

 

 

 

Finding RPM with Gear Ratio, Speed, Tire Size

OD is your transmission's overdrive ratio. If you do not have overdrive, use "1". If you have overdrive, but don't know the ratio, a good guess is ".7".
Gear Ratio Speed (MPH) OD (see above) Tire Diam. (in) RPM
Alternatively, you may use this calculator if you don't know your tire diameter. Instead, enter the 3 numbers listed on the side of the tire. For example, if the tire says something like "225/50/R16", use 225 for tire width, 50 for aspect ratio, and 16 for rim diameter.
Gear Ratio Speed (MPH) OD (see above) Tire Width (mm) Aspect Ratio Diameter of rim (in) RPM

Correcting Speedometer for Tire Size

Original Tire Diam. (in) New Tire Diam. (in) Speedometer Reading Real Speed

 

 

 

 

 

 

 

 

 

 

 

 

Finding Displacement with Bore, Stroke, Cylinders

Bore (inches) Stroke (inches) # of cyls Displace- ment (ci) Displace- ment (L)

Calculate Cylinder Volume

Bore Stroke cylinder Volume

Calculate Stroke

Displacement Bore # cylinder Stroke

Finding Forced Induction Compression Ratio

If your motor compression is 9:1, put 9 in the "motor compression" box.
Motor compression Boost (psi) Effective compression

Calculate Chamber Volume

cylinder Volume compression Ratio chamber Volume

 

 

 

 

 

 

 

 

 

 

 

 

Fuel Requirements in Gallons Per Hour

This formula will calculate the approximate fuel needs for an engine based on horsepower at wide open throttle. The formula came from the Holley website. It's just a general guideline, but will get you in the ballpark. It says you should use about .5 lbs of fuel per hour per horsepower at wide open throttle.
HP@WOT Results

Fuel Injector Sizing Requirements

  • In most cases a naturally aspirated engine will have a B.S.F.c of .50. This means that the engine will use .50 lbs. of fuel per hour for each horsepower it produces. Turbocharged engines will want to be at .60 lbs. per hour or higher.
  • Most injectors will max out at 80% duty cycle and this is the accepted industry standard.
    • HP@WOT BSFc Inj Duty cycle # of Injectors Results lb/hour

    Maximum Fuel Injector HP Support

  • In most cases a naturally aspirated engine will have a B.S.F.c of .50. This means that the engine will use .50 lbs. of fuel per hour for each horsepower it produces. Turbocharged engines will want to be at .60 lbs. per hour or higher.
  • Most injectors will max out at 80% duty cycle and this is the accepted industry standard.
    • Inj lb/hour BSFc Inj Duty cycle # of Injs Results lb/hour