re all
I come back cause i have a little matter . Speak with real value:
car definition : Weight : 1300 kg
3rd gear ration : 4.48 : 1 Differential : 1 ( i guess ) tire dimension : 175/65 R14
and these 2 obd2 value : ( time;rpm)
0,682926833629608;2029
0,852926835417747;2076
so .. ( in a metric system )
/!\ 1 pouce =3D 25.4 millimetre diameter wheel =3D (((width *0.Aspect_ratio)*2) +(jante_diameter
*25.4) diameter =3D (175*0.65
*2)+(14*25.4) =3D 583.1 mm =3D 0.5831 m so circonference =3D PI * d =3D 1.831 m
after we compute the velocity ! at 1000 rpm, speed is :
1000(rpm) * ( 1 / Rv ) =3D Z tr/min Z * 60 =3D Z tr/h Z*circonference_of_wheel =3D V en m/h V/1000 =3D V en Km/h simplification : ((1000/Rv)
*60 * Ct )/1000 =3D V soit (1/Rv)
* 60 * Ct =3D V in hm/h @ 1000 rpm for X rpm : (X * (1/Rv)
* 60 *Ct )/1000 =3D V en km/H @ X rpm with Z,X=3Drpm, Rv =3D ( gear ratio * diff ) this formula is good, i check her with my technical book of my car , i get the right speed at 1000 rpm !
so .. for our 2 obd2 value !! ( get in 3rd gear )
to translate km/h to m/S i use the formula : (Speed / 3600 ) * 1000
0,682926833629608;2029 --> (2029 * (1/4.48)
* 60 *1.831) / 1000 =3D
49,75 km/h - > 13.819 m/s
0,852926835417747;2076 --> 50,90 km/h -> 14.138 m/s
now i use the acceleration formula : a =3D (v2-v1) / (t2 - t1) =3D 0.31 /
0=2E17 =3D 1.88 m/s=B2
we know that force =3D mass * acceleration : 1300 * 1.88 =3D 2444 newton
and work(nm) =3D force * displacement =3D 2444 * 0.31 =3D 757.64 newton.meter or 757.64/1.356 =3D 558.7 lb-ft
i know that i havent applie the wind drag factor yet, but this value looks me too high . Is my reasonement wrong ? or the wind factor very important to get correct value
I know that my car cant have more than 185 nm of torque !
Thanks, and sorry for my poor english