Spark Exhaust Bent Tube 90° Ø 48 × 1.0 mm Stainless Steel Universal G9149

Forty-eight millimetres at ninety degrees. A right angle at the diameter a four-into-one collector feeds — and one of the harder pieces in the range to form.

Key Features

• Mandrel-formed 90° bend, AISI 304 stainless steel.
• Ø 48 mm outside, 1.0 mm wall thickness.
• Straight tangents at both ends.
• Matches Spark's 48 mm straight tube, article G9012.
• Spark part number G9149, made in Mantova, Italy.

Up Behind the Shock

A high-mounted or underseat layout has to leave the collector, get past the shock and climb. The climb is often a right angle because the shock leaves no room for a longer sweep.

The reservoir is what catches people out. It sits away from the shock body, it is easy to miss on a drawing, and unlike the shock it does not move when the suspension does — so a pipe that clears the damper can still foul the bottle.

Where the System Resonates

Bends change more than the routing. A pipe is an acoustic instrument, and where the corners fall changes which frequencies reinforce and which cancel. Two systems of the same length and diameter can sound noticeably different because one has its corners in different places.

It is not something worth calculating on a one-off build, but it is worth knowing before blaming the silencer for a note nobody expected.

Ceramic Coating a Formed Bend

Coating goes on after all the welding, never before — a torch destroys it locally and the repair is a re-coat of the whole part. It also wants the surface clean and dry to the standard the coater specifies, which usually means shipping the piece unassembled.

Never Reheat a Formed Bend

The metal in a bend has been work-hardened by forming, and heating it to red to persuade it into a slightly different angle undoes that unevenly. What comes out is a piece with a soft patch on the outer heel — precisely where the wall is already thinnest.

If the angle is wrong, cut and rejoin. Do not bend it further.

Supporting the Corner

A right angle is the highest-stress point in a fabricated system: vibration turns into bending there, and the weld at the tangent concentrates it. Put a mount within a hand's width, and make at least one mount in the run rubber-isolated.

Ordering

One bend per article. Spark builds 30°, 45° and 90° at this diameter.