Pipe Engineering

[baz-r]

if you make 4-2-1 headers dont join un ballanced pairs thats the rule so 1+4 and 2+3 join first.
other wise the cyl the gets the exhaust stroke first creates high pressure wave in the exhaust that its joined to for the cyl that gets exhaust stroke next and as a 4pot will always have a fireing order where 1+2 and 3+4 next to each other in the firing order

the gap is 180deg bigger with a 1+4,2+3 split and power ballance is corrected

[robo]

I tried not to go into the science on headers. it was really a tube exercise. The collector thing and interconnection of pipes is probably more to do with firing orders of which there are many variants . http://en.wikipedia.org/wiki/Firing_order.

There are also many headers that are on the market that dont follow any particular order







Bob

[baz-r]

sorry it was only a pointer for others as i seen it in your pic

its not so much of an issue with longer headers as its a harmonic thing thats a complete mine field.

its all because there are points in valve timing (overlap) where both exhaust and inlet are open at the same time (more so with sporty cams) and the exiting exaust gas pulls in the fresh charge. get it all wrong and a pressure wave knocks it back in.

[Numplumb]

Hi not trying to argue but you measure either inside or outside for copper pipe work, usually for 90 degree bends its easier to use outside to outside, centre to centre is used for steel when using hydrolic bending machines.

[robo]

Originally Posted by Numplumb

Hi not trying to argue but you measure either inside or outside for copper pipe work, usually for 90 degree bends its easier to use outside to outside, centre to centre is used for steel when using hydrolic bending machines.

If there is a better way crack on and give us a demo, you are right we bend up shit loads of steel hydraulic pipe . Its a way I was shown thats really simple and accurate so never gave it a thought. Always up for learning.

Bob