Donate $1.00 $2.00 $3.00 $4.00 $5.00 $10.00 $15.00 $20.00 $25.00 to FBody.com BUY A FBody.com T-Shirt! FBody.com HomePages   More Information/Signup   Login YourName@FBody.com Email   More Information/Signup   Login Message Forums   Anything Goes - Most anything...   LS1   LT1   3rd Gen   1st & 2nd Gen   V6   Drag Race   Events/Gatherings   FAQ   Search Classifieds   Parts For Sale   Parts Wanted   Cars For Sale   Cars Wanted   Group Purchases Timeslips/Photos   Member Timeslips/Photos   Add / Edit Record(s) Product Reviews   Product Reviews   Write A Review Member Services   Member Locator   Current Connections   Lost Password   Register   Edit Profile   Logout Install Guides   Install Guides   Performance Calculators   Add A Guide Shop Directory   Shop Listing   Add Shop Live Chat Room   Member's Only Track Directory   List Tracks   Add Track Calendar   Member Calendar Columns with a grey background are output. Fill in all other columns and click the "Calculate" button to use. Finding Horsepower with Weight and Trap Speed. Vehicle Weight (lbs) 1/4 Mile Trap MPH Your Estimated Horsepower Finding Horsepower from Torque and RPM. Torque (ft-lbs) RPM HP Finding ET and MPH with Weight and Horsepower. Vehicle Weight (lbs) Horse- Power Estimated E.T Trap Speed Adjusting ET for Elevation. Old ET (s) Elevation (ft) New ET Finding RPM with Gear Ratio, Speed, and 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 New Tires. Original Tire Diam. (in) New Tire Diam. (in) Speedometer Reading Real Speed Formulas for Bore, Stroke Displacement Finding Displacement with Bore, Stroke, and # of 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 Formulas for Compression Ratio Finding Effective Compression with Compression and Boost. 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 Formulas for Fuel Requirements 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 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 Max HP by injector size 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 If it looks (c) it probably is - All work done by Jim Hogan