exhaust calculations

[AKAY]

hey guys i want comments on this calculations.
1-inside diameter of the primary pipes
ID = sq root [2cv / {25 x (P + 3)}] x 2
Where
Cv=cylinder volume in cubic cm
2-P = 850 X ED / RPM - 3
ED = 180+24.6= 204.6 degree.
3-Collector length is given by:
CL=(ID2-ID3)/2)*COTA
ID2=COLLECTOR INLET DIAMETER .
4-ID3=sq root[(cc*2)/(p+3)*25]*2
5- TL=(P+3)-CL.
iwant to know what (id2 and id3) mean
and if id2 collector inlet diameter there aren't any equation for it or i didn't get it.
and there are any calculation missing in exhaust manifold? except silencer volume

[AKAY]

hey guys i want comments on this calculations.
1-inside diameter of the primary pipes
ID = sq root [2cv / {25 x (P + 3)}] x 2
Where
Cv=cylinder volume in cubic cm
2-P = 850 X ED / RPM - 3
ED = 180+24.6= 204.6 degree.
3-Collector length is given by:
CL=(ID2-ID3)/2)*COTA
ID2=COLLECTOR INLET DIAMETER .
4-ID3=sq root[(cc*2)/(p+3)*25]*2
5- TL=(P+3)-CL.
iwant to know what (id2 and id3) mean
and if id2 collector inlet diameter there aren't any equation for it or i didn't get it.
and there are any calculation missing in exhaust manifold? except silencer volume

[Xeilos]

I may be out of line with this, but you are asking help with trying to figure out what two terms are from an equation you found.

Before someone else flames this I am going to make two suggestions:

1) Go back to first principles (a skill a lot of people lack) and try to figure out (this is something you do yourself) what the question is attempting to do. Do not follow equations blindly without understanding where they came from.

2) Read through the paper or book and ask the person where you got these equations from to explain them. If that fails try to do it yourself. At the very least post where this equation came from.

Rather than posting randomly on this forum asking us to solve stuff for you, stop and do some critical reasoning (it is far easier than you think and more rewarding).

Plugging and chugging while fun is NOT the answer for an engineer. You are training to be one, so engineer something instead of relying on blind equations.