Did any of you try to make one??? My friend told me that the best thing about exhaust should be for it to be straight as much as possible.. ..and what makes exhaust system good quality ????? material, lenght???
MAYBE i ALSO ADD THE QUESTION OF THE AIR INTAKE.. i SEE SOME OF THEM ON EBAY COST FROM THE RANGE OF 50 TO 200$ wHAT IS THE DIFFERENCE BETWEEN THEM?
The miniumum number of bends and fittings should be pursued. As you start
Googling about exhausts you will soon find a preoccupation with mandrel
bends, a supposed panacea almost as popular as pod filters.
Long radius pulled bends and gradual transitions are the best method of minimising pressure drop in the pipe. Mandrel bends tend to have a tighter radius, but lose little cross sectional area, of course the first speed bump you nail will change all that. Crimped bends aren't as bad as made out, but obviously the ribbing can produce some losses.
Transitional fittings like collectors should have reasonable taper to reduce high pressure regions on the inside skin of the pipe that effectively choke flow. Butt joining a smaller pipe to a larger pipe has a fairly significant loss coefficient.
To size your exhaust pipe diameter and runner lengths you really need to know your exhaust events, torque requirements and engine power. Similarly the intake is sized on engine requirements.