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hi ,
For everybodys info just a few facts from online magazine "carcraft "
Exhaust
There are some good formulas for calculating the exhaust diameters . Basically they reinforce what some of us have used prior also .
1st select where u want peak toque ????? rpm
2nd cu inch of cylinder
3rd size of primary pipe 1 inch or say 1.25 inch
Calculate area of pipe eg
1inch pipe
3.1416 x .5 x.5 =.7854
1.25 inch pipe
3.1416 x .625 x .625 = 1.22718752
1.50 pipe
3.1416 x .750 x .750= 1.76715
peak torque rpm =pipe area x 88200 divide by cu inches of cylinder
vanguard 35 cuin v twin ........primary pipe 17.5 cuin 1 cylinder
1 inch pipe =3958.42 rpm ideal
1.25 inch = 6185.02 rpm
1.5 inch = 8906.44 rpm
35 cu inch collector muffler tail pipe etc eg 2 into 1 system
1.5 inch =4453.22 rpm
The real world example of this is that the Bandolero racing series mainly use 1 inch primaries on there vanguards and of course some mower racing do also .
1.25 primaries seems popular on the fastest mowers also
primary length
As we all no this mainly is dependant upon the chassis or body . The mower guys seem to prefer 12-18 inches long
The info as I said earlier is from car craft magazine and as u would expect the development has been driven from the small block chev etc
The figures are performance based [the formulas assume a certain gas flow thru the pipe ,the ideal or balance between to much or to little flow ] This is a complete discussion by itself ....
hope this helps some one
tomo
For everybodys info just a few facts from online magazine "carcraft "
Exhaust
There are some good formulas for calculating the exhaust diameters . Basically they reinforce what some of us have used prior also .
1st select where u want peak toque ????? rpm
2nd cu inch of cylinder
3rd size of primary pipe 1 inch or say 1.25 inch
Calculate area of pipe eg
1inch pipe
3.1416 x .5 x.5 =.7854
1.25 inch pipe
3.1416 x .625 x .625 = 1.22718752
1.50 pipe
3.1416 x .750 x .750= 1.76715
peak torque rpm =pipe area x 88200 divide by cu inches of cylinder
vanguard 35 cuin v twin ........primary pipe 17.5 cuin 1 cylinder
1 inch pipe =3958.42 rpm ideal
1.25 inch = 6185.02 rpm
1.5 inch = 8906.44 rpm
35 cu inch collector muffler tail pipe etc eg 2 into 1 system
1.5 inch =4453.22 rpm
The real world example of this is that the Bandolero racing series mainly use 1 inch primaries on there vanguards and of course some mower racing do also .
1.25 primaries seems popular on the fastest mowers also
primary length
As we all no this mainly is dependant upon the chassis or body . The mower guys seem to prefer 12-18 inches long
The info as I said earlier is from car craft magazine and as u would expect the development has been driven from the small block chev etc
The figures are performance based [the formulas assume a certain gas flow thru the pipe ,the ideal or balance between to much or to little flow ] This is a complete discussion by itself ....
hope this helps some one
tomo