Straight Flow Straight Pipes

Straight Flow’s straight pipes are lengths of plain tube for fabricating an exhaust or intake, in stainless steel or aluminium. The stainless tube is grade 304, sold in 50 cm and 1 m lengths from 40 mm to 89.9 mm outside diameter. Each title gives the wall thickness too: 1.5 mm for most sizes, 1.6 mm or 2 mm for some. The aluminium tube comes in 50 cm lengths from 38 mm to 102 mm.

The choice follows the job. Stainless 304 is the material for exhaust sections that see heat and water, and it welds to the stainless bends, flanges and V-band clamps in the same range. Aluminium tube is light and easy to work, which makes it a usual choice for intake and intercooler pipework, but it is not suited to exhaust temperatures.

Diameters are outside diameters, so a 63.5 mm tube takes 63.5 mm bends and couplers with a 63.5 mm bore. Wall thickness matters when welding: a thinner wall is lighter but needs more care with heat.

Order enough for offcuts and trial fits; a 1 m length gives spare to recut a piece that comes out short.