Sterling

I would like to start a thread specifically to be archived that is basically nothing but a collection of auto-related equasions. Everybody- Contribute to this, whatever ya got.
Maybe mar3 has the "magic boost" equasion (hint-hint), and someone else has the latest "automobile depreciation" equasion.

Anything pertaining to cars, MPG, power and performance, monetary value...whatever.
It'll be a data thread to theorize about stuff, and a great way to start cool arguements!
What say the High Council?

I found this that I wrote down forever ago; don't even know where I got it...

Vs= 3[the square root of (3Reb)]

Vs= Swept Volume
R= Generating Radius
e= Eccentric Radius
b= Rotor Depth

(Don't ask me how to use this particular equasion! )
And can someone please show us how to type the symbol for "square root"?!

inittab

You mean this? √

Hans

ill get easy ones!!!

Pressure ratio is
(14.7+boost psi)/14.7

Air flow rate is (cid * rpms * 1.5(.5 for boingers) * Ev)/1728= XXX cfm's

*******(i hope the 1.5 is right, thats what I think should work and i get some realistic numbers)********

using
69.9cid (1.146*61) 1 liter is 61cid
7000rpms
85% for Ve

I got 361cfm

does this sound about right for a mostly stock Rex?

to get cfm for boosted motors multiple times PR

for example

PR 1.5(~7psi) * 361cfm = 542cfm

also when comparing to a compressor flow map that is in Pounds per Minute
(lbs/min), multiply CFM by 0.069 to convert CFM to lbs/min


hope this helps,
oh and most of this is from Corky Bell's book btw

Hans

Good site, mostly boingers but good site non-the-less

http://www.prestage.com/carmath/

MikeLMR

Don't forget the most important Equation

Force = Mass x Acceleration

therfore Acceleration = Force/Mass

therfore less mass = more acceleration for the same force

= one of the cheapest ways to make a car go faster

crankit

How did this thread get a 5***** rating? Nice idea but I don't agee with the rating so early.

Orange!FD

Horsepower = (Torque * 2*pi * RPM/60) / 550
or
HP = Torque * RPM / 5252.11


For example HP = (170 ft-lb * 6.28 * 7400 rpm /60) / 550

HP = 239.5

MikeLMR

thats better orangeFD... I was about to correct you ... 1000ftlbs at 7400rpm = >1400 HP !

you can simplify that equation to

(Torque x Engine speed) / 5252 = Horsepower

this also explains why dyno print outs cross at 5252 Rpm presumuming that H.P and torque are on the same scale

Orange!FD

Yeah, since it isn't late here, my excuse is: It's early.