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 Air / Fuel Air Flow Fuel Injector Sizing Fuel Injector Sizing 2 Fuel Injector Pressure Change Intercooler Efficiency
 Engine Building Cam Timing Events Calc Adv Intake Valve Closing Compression Ratio Compression Tester Cylinder Head Volume Displacement Dynamic Compression Ratio Effective Compression Ratio Piston Speed Piston Volume Pressure Ratio
 Gearing Rear End Gear Ratio Speed for RPM range Speed for RPM range 2 Tire diameter
 Horsepower 60' G Force HP 1/4 mi MPH - Auto Lookup HP from 1/4 mi MPH HP from 1/4 mi ET HP from 1/8 mi MPH MPH & ET from HP Wind Resistance
 Weather Density Altitude 1 Density Altitude 2 NHRA Correction Factors Timeslip Cor. to Sea Level Timeslip Cor. to Another DA Timeslip Cor. DA Auto Lookup Auto Math Calculations  Paid Subscription Required for all calculators.

Air / Fuel

Air Flow / Fuel Flow - This calculation will determine the amount of air and fuel flow for a specified RPM. You can use this calculation to determine carburetor sizing if you enter the maximum RPM.

Fuel Injector Sizing - This calculation determines injector size based on max horsepower and number of cylinders

Fuel Injector Sizing 2 - This calculation determines the amount of horsepower an injector will support.

Fuel Injector Flow Pressure Change - This calculation determines the amount of flow a fuel injector will change with a change in fuel pressure.

Intercooler Efficiency - This calculator will determine your intercooler efficiency. You'll need to know the ambient air temperature, Intercooler Inlet Air Temp, and Intercooler Outlet Air Temp. The result will be the efficiency of the intercooler.

Engine Building

Cam Timing Events - This calculation will determine the valve events for a camshaft based on published camshaft duration specifications. Inputs are camshaft duration @ 0.05" lift or advertised duration, lobe separation, and intake centerline.

Calculate Advertised Intake Valve Closing ABDC - This calculation will determine the advertised intake valve closing point needed for calculating dynamic compression ratio, DCR. Sometimes cam companies only publish 0.050" valve timing events. The Intake valve closing event ABDC is crucial in determining DCR for your engine.

Compression Ratio - This calculation will determine your engine's compression ratio. You need to know the bore, stroke, cylinder head volume, deck height, head gasket bore, head gasket thickness, and piston dish volume. The result is a very accurate compression ratio calculation.

Dynamic Compression Ratio - This calculation will determine your engine's dynamic compression ratio. This calculation has all the information from the previous compression calculation but includes cam timing. This will allow you to determine the dynamic compression ratio based on the intake valve timing.

Pressure Ratio - This calculation will determine your engine's pressure ratio. You need to have tested your engine's compression with a compression tester and the barometric test pressure. The result will be the pressure ratio of your engine. This can be compared to the actual compression ratio of your engine.

Compression Tester Gauge Reading - This calculation will determine a "ballpark" reading for your compression tester based on your engine's compression ratio. You need to know the compression ratio of the engine and barometric test pressure and the calculation will return a number your engine should read on a compression tester gauge.

Cylinder Head Volume - Trying to figure out which cylinder head volume will give the right compression ratio for your motor. Use this calculation to determine the chamber volume of a cylinder head by entering your desired compression ratio, bore, stroke, deck height, head gasket bore, head gasket thickness, and piston dish volume.

Piston Volume - Use this calculator to compute the piston dish / dome volume. Enter the the cylinder bore, depth of the piston in the bore, and the measured volume. The result is a very accurate piston volume measurement.

Piston Speed - Use this calculator to compute the average piston speed and the maximum acceleration of the piston. Enter the engine stroke and connecting rod length.

Engine Displacement - This calculation will determine the displacement of your motor in cubic inches and in liters. Just enter the bore, stroke, and number of cylinders.

Effective Compression Ratio - This calculation will determine the effective compression ratio from the static compression ratio and the amount of boost from your supercharger or turbocharger.

Gearing

Rear End Gear Ratio - Not sure what rear end gear ratio you have in your car? Try this calculation and it should give you an idea of your gear ratio in the rear end. You need to know the rpm's of the motor at a certain speed as indicated by your speedometer.

Speed for RPM range - This formula will calculate the speed of the vehicle at a RPM. You enter your tire diameter and your rear end gear ratio and it will display vehicle speed an RPM range from 1000 - 8000 RPM.

Speed for RPM range comparing rear gears - This calculation will display two tables with mph vs rpm range for two different gear ratios. It's handy for comparing different speeds for two different gear ratios. In other words how will changing my stock 2.73 gears to 4.11's effect my cruising speed. Same as Speed for RPM range below except with an additional gear ratio input.

Tire diameter - This formula will calculate the tire diameter from the tread width, series, and wheel diameter. In other words the stamping on the tire, example 275 60R15.

Horsepower

HP from 1/4 mi ET - This formula will calculate HP using the elapsed time (ET) from a 1/4 mi time slip.

HP 1/4 mi MPH - Auto Lookup - This calculator will calculate wheel horsepower from your timeslip. Select your dragstrip, run date & time, ET, trap speed, vehicle weight, drag coefficient, and frontal area. The calculator automatically gets weather information, dragstrip information (1/8 & 1/4 mile) and determines uncorrected WHP, corrected WHP to SAE J1349 conditions.

HP from 1/4 mi MPH - This formula will calculate HP using the MPH from a 1/4 mi time slip.

HP from 1/8 mi MPH - Don't have a 1/4 mi dragstrip in your area but have 1/8 mi timeslips. Then use this formula to calculate HP using the MPH from a 1/8 mi time slip.

Trap speed & ET from Wheel HP - If you know the weight of your car (with you in it) and know the peak wheel HP as measured by a chassis dyno this calculation will estimate the trap speed in MPH and the Elapsed Time (ET) in the quarter mile.

Wind drag HP - Determine the amount of HP is required to over come the wind drag for a certain speed. All you need to know is the front area and drag coefficient of your car.

Launch G Force - This calculation will tell you how many G's your pulling off the line and your speed at 60'. All you need is a timeslip with a 60' time.

Weather

Calculate Density Altitude 1 - The density of air changes which in turn affects the HP generated by an internal combustion engine. Density altitude is defined as: The altitude in the international standard atmosphere at which the air density would be equal to the actual air density at the place of observation. "Density Altitude" is the pressure altitude adjusted for non-standard temperature. Both increase in temperature and increase in humidity cause a reduction in air density. Thus in hot and humid conditions the density altitude at a particular location may be significantly higher than the geometric altitude.

Calculate Density Altitude 2 - Density altitude calculated from Altimeter setting, temperature, altitude, and dew point.

Correct 1/4 mi. Timeslip to Sea Level - The density of air changes which in turn affects the HP generated by an internal combustion engine. Use this calculator to correct your timeslips based on the density altitude (DA) to sea level.

Correct 1/4 mi. Timeslip to New Density Altitude - Correct a timeslip from one density altitude to another density altitude. Very handy when comparing timeslips.

Correct 1/4 mi. Timeslip with Density Altitude Auto Lookup - To use this calculator enter the date, time, select dragstrip, ET, and trap speed. This calculator will look up the weather information for the date you entered from the closest airport to the dragstrip you select. Based on these weather conditions the calculator will calculate the density altitude and correct the timeslip to sea level.

NHRA Correction Factors - This is not a calculation but a table you can use to correct your timeslips to sea level if you run at a track where the air is thin. Latest Forum Posts       