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GENERAL => General => Topic started by: turbo90gp on October 26, 2004, 08:44:16 PM

Title: Who want's formulas?!
Post by: turbo90gp on October 26, 2004, 08:44:16 PM
I have formulas for Ohm's law, Resistance, Total Resistance in a series circuit, Horsepower, Horsepower Loss, Gear Ratio, Over all Transmission Ratio, Engine RPM, MPH, Force, Pressure, and Area, Volume of a Cylinder, Compression Ratio, Engine Displacement, Torque, Exhaust Header Tubing Diameter, Theoretical air capacity of an Engine, Volumetric Efficiency, Tire DIameter, New effective drive ratio, Drive Axle Ratio, True Speed, Equivalent Indicated Speed, Percent Error, Cornering Force, and Velocity.  If anyone needs any of these formulas, please contact me.  Of, if someone would like to make it a sticky or whatever, just let me know and I will type out all of the formulas.  Just figured that I have taken so much from this forum, that I can give back what I can!   :shock:
Title: Who want's formulas?!
Post by: TGPilot on October 29, 2004, 08:36:02 PM
You are now a Sticky...write away! 8)
Title: Who want's formulas?!
Post by: turbo90gp on November 02, 2004, 08:14:13 PM
Ok Here we go!
Ohm's Law
E=IxR  I=E/R  R=E/I

Where E is the electromotive force measured in Volts (V); I is the current flow measured in Amperes (amps (A))  and R is the resistance measured in Ohms.

Total Resistance in a parallel circuit
The total resistance R is equal to:
1/(1/R1)+1/(1/R2)+...+1/(1/Rn)
Where R1, R2....Rn, etc., are the resistances of each resistor connected in parallel.  Each resistance is measured in Ohms.

Total resistance in a series circuit
Rtotal= R1+R2+...+Rn
Where R1, R2,...Rn are the resistances of each resistor connected in a series.  Each resistance in measured in Ohms.

Horsepower
1hp=746 Watts or Hp=(RPMxTorque)/5252

Horsepower Loss
(Elevation in feet/1000) x.03xSea Level Horsepower

Gear Ratio
Driven gear/Drive gear

Overall Transmission Ratio
OTR=(Front counter gear/Clutch shaft gear)x(Last gear/ Last counter gear in use)

OTR=(Front driven gear/ front drive gear)x(Rear driven gear/rear drive gear)
Engine revolutions per minute
RPM=(168xRxMph)/R
Where MPH Is the vehicle ground speed in MPH, R is the rolling radius in inches of the loaded-driving tire, and R is the overall gear ratio.

MPH
Mph=(RPMxR)/(168/R)
Where MPH is the vehicle ground speed in MPH, R is the roling radius in inches of the loaded-driving tire, and R is the overall gear ratio, and 168 is a constant.

Force, Pressure, Area
F=PxA  P=F/A  A=F/P
Where F is the force in pounds or kilograms, P is the pressure in PSI or Kilopascals (kPa) and A is the area in square inches or square centemeters.

Volume of a cylinder
V=.785(D^2)L
Where D is the diameter of the cylinder (D^2= D squared), L is the length of the cylinder, and .785 is a constant.

Compression Ratio
CR=(Piston Displacement+Combustion Volume)/Combustion Volume

or

CR=(Cylinder Volume+Deck Height Volume+Head gasket volume+combustion chamber volume)/(Deck Height Volume+Head Gasket Volume+Combustion chamber volume)

OR

CR=(.7854x(bore^2)x(stroke+deck height+head gasket thickness)+combustion chamber volume)/(.7854x(Bore^2)x(Deck height+head gasket thickness)+combustion chamber voulme)

Where (Bore^2) is bore squared and .7854 is constant


Engine Displacement
Displacement=.7854x(Bore^2)xStrokexNumber of cylinders
Where bore and stroke are both either in inches or millimeters, and .7854 is constant.  If they are in inches, the displacement is inches cubed, and if measurements are in MM, displacement is MM cubed.

Displacement in Cubic Centemeters=(.7854x(Bore^2)xStrokexNumber of cylinders)/1,000

Displacement in Liters=(.7854x(Bore^2)xStrokexNumber of cylinders)/1,000,000
This is only if bore and stroke are in MM

Torque
(5252xHorsepower)/RPM
Torque is measures in lb-ft and the number 5252 is constant.

Exhaust header tubing diameter
Diameter=Square root of ((CIDx1900)/LengthxRPM)

Theoretical air capacity of an engine
Theoretical air capacity (CFM)=(RPMxDisplacement)/2

If engine displacement is given in cubic inches, the number is very large.  To make it more managable, refer to the terms of cubic feet per minute (CFM).  To convert cubic inches to cubic feet, divide the cubic inche number by 1728.  Since there are 1728 cubic inches per foot, the formula then becomes:
CFM=(RPMxDisplacement)/3456

Volumetric Efficiency
VE=(Actual air capacity(CFM)x100)/Theoretical air capacity(CFM)


Tire Diameter(In Inches)
Tire Diameter=((Section WidthxAspect Ratio)/2540)x2+Rim Diameter

or

Tire Diameter=((Section widthxAspect Ratio)/1270)+Rim Diameter
Where 2540 and 1270 are constants.



New effictive drive ratio
New Effictive drive ratio=(Old tire diameter/new tire diameter)xDrive axle ratio

Drive Axle Ratio
New drive ratio=(New tire diameter/old tire diameter)xOrigional drive ratio


True Speed
True speed=(New tire diameter/old tire diameter)xIndicated Speed

OR

True speed=(3600/seconds per mile)


Equivalent indicated speed
Equivalent indicated speed=(Old tire diameter/new tire diameter)xTrue Speed

Percent Error
Percent Error=((True Speed-Indicated speed)/True speed)x100

Cornering Force
Cornering force is usually expressed in it's relationship to gravity, or G's
Cornering force=(Velocity^2)/(32xRadius)

OR

Cornering force=(Velocity^2)/(16xDiameter)

Where velocity is expressed in feet per second and the radius or diameter of the turn is given in feet.  If a skidpad is used, the cornering force is:
Cornering force=(1.23xRadius)/(Time^2)

where the radius is in feet, time is in seconds, 1.23 is constant and (^2) means squared.

Velocity
To convert velocity in MPH to velicity in Feet per second(FPS), use either of the following formulas:
Velocity(FPS)=Velocity(MPH)x(22/15)

or

Velocity(FPS)=Velocity(MPH)x1.467

where the constant is (22/15)=1.467
Title: Who want's formulas?!
Post by: twinturbosedan on November 03, 2004, 08:46:38 PM
KICK ASS thank you :D