Quarter Mile Masthead


A Horsepower Calculator from Quarter Mile Performance

Fill in your values by double clicking on "number". Then click on when finished.
Top End Speed (the traps) Weight of Your Car as Run (with you in it)

The horsepower is hp.

A MPH Calculator from RPM and Gearing

Fill in your values by double clicking on "number". Then click on when finished. You can also now calculate when using different transmission gear ratios, like in first gear or in overdrive. If you do not know this ratio, you can simply put in 1.00 as this is the typical 4th gear ratio of most 4 sp and 5 sp manual transmissions. See the chart below the table for typical ratios.

This chart has been revised with actual ratios now. I made a few mistakes on the first pass and have corrected them now.

RPM you wish to check Rear Axle Gear ratio (i.e., 3.08, 3.55, etc.) Transmission Gear ratio (i.e., 2.54, 1.43, 1.00, etc.) Tire diameter in inches (24.5, 26, 27.5, etc.) 

The speed in MPH is miles per hour.

 The same tire and RPM will give the following speeds based on the following gear ratio changes.


  
2.59 2.73 3.08 3.36 3.55 3.70 4.11 4.56

Typical Transmission Ratios

Transmission 1st 2nd 3rd 4th 5th 6th Rev
Corvette 3sp  2.21 1.32 1.00 2.51
Muncie Wide 4sp pre-'74 2.52 1.88 1.46 1.00 2.59
Muncie Close 4sp pre-'74 2.20 1.64 1.28 1.00 2.27
Borg Warner T-10 Wide 4sp early 2.56 1.91 1.48 1.00 2.64
Borg Warner T-10 Close 4sp early 2.20 1.66 1.31 1.00 2.26
Borg Warner Wide 4sp '74 up 2.64 1.75 1.34 1.00 2.55
Borg Warner Close 4sp '74 up 2.43 1.61 1.23 1.00 2.35
ZF 6 speed (Corvette)  2.64 1.78 1.30 1.00 0.74 0.49
Powerglide 1.82 1.00 1.82 R
Turbo 350 2.52 1.52 1.00 1.94 R
Turbo 400 2.48 1.48 1.00 2.08 R
700R4 3.06 1.63 1.00 .70 2.29 R
Richmond OverDrive 6 sp 3.27 2.13 1.57 1.23 1.00 0.76

Drag Performance Calculator
Vehicle Weight (in pounds):
Vehicle Horsepower:
RPM through lights (finish line):
Tire Diameter (Height) in Inches:


1/4 Mile ET:
1/4 Mile Top End Speed:
Ideal Ratio:

 

AXLE RATIO CALCULATOR

"RESET" Before each combination!
SPEED IN MPH 
DESIRED RPM 
TIRE DIAMETER IN INCHES 
TRANSMISSION HIGH GEAR RATIO to-1

AXLE RATIO NEEDED to-1

2700 to 3000 RPM @ 65 MPH is recomended.
3000 to 3500 RPM will give better power.
2200 to 2700 RPM will increase fuel economy.