So you changed your tires for some big meaty ones for better tracksion, but now your speedo is off. Use this calculator to get an aproximate correction.

  Speedo conversion 
Original Tire Diameter:  
New Tire Diameter:  		 Speedometer Reading (MPH):  Corrected Speed (MPH): 


So you changed your tire size and you want your vehicle to preform like it did or want your gas milage back. Use this calculator to figure out what gear ratio you need to get back your original performance or milage.

  Find your new Gear Ratio  
New Tire Diameter:  
Old Tire Diameter:  		 Current Gear Ratio:  New Gear Ratio: 
 


Tired of trying to have your buddy pace your ride so you know how fast your going? If you have a tack and know your gear ratio and tire diameter you can use this calculator to figure out your speed.

  Find your MPH 
RPM:  Tire Diameter:  
Axle Ratio: Transmis Ratio: 		 MPH: 



Ever wonder how fast your engine is turning at any given speed or gear? Use the following calculator to find out.

  Find your RPM 
MPH: Axle Ratio: Transmis Ratio: 
Tire Diameter:  		 RPM: 


Want to know how much displacement you have? Use this calculator to figure it out.

  Displacement calculation 
Cylinders: Bore size: Stroke: 
Displacement: 


Want to know how big a carb to run?? Use this Calculator to figure it out.
Stock engines have about 85% VE. Intake and exhaust would be about 90% VE.
Aftermarket heads, manifolds and exhaust is about 95% VE.
VE's are decimal equivilants. IE 95% = .95 and 125% = 1.25 ect...

  CFM calculation 
Displacement: RPM: 
Volumetric efficiancy: 
CFM required: 



Use this one to convert the Metric tire size rating over to a diameter in inches.

/ R
Example: 195/75R15
 
 
 
Tire Diameter: inches


If you have a 1/4 mile time slip
and know the weight of your vehicle then;

1) Input the Weight of your vehicle (with driver!),
and your 1/4-mile Trap speed.

2) Click Tell Me!.

 This form will give your approximate rear wheel horsepower.

Vehicle Weight
with Driver
 In Pounds
(e.g. 3200lb.)

1/4 Mile
Trap Speed
in MPH

Your Rear Wheel
Horsepower
is:

 




If you have made a Chassis Dyno pull and know your vehicles weight then;

1) Input the Vehicle Weight with Driver and Rear Wheel Horsepower.
2) Click Tell Me!.

This form will estimate the elapsed time your
Vehicle should run and its approximate 1/4 trap speed.

Vehicle Weight
with Driver
In Pounds
(e.g.3200lb)

Rear Wheel
Horsepower

Estimated
E.T (sec.)

Trap Speed
in MPH