Spark Exhaust Bent Tube 90° Ø 45 × 1.0 mm Stainless Steel Universal G9106

Forty-five millimetres through ninety degrees. A large-bore right angle, in one of only two diameters Spark also bends into a complete U.

Key Features

• Mandrel-formed 90° bend, AISI 304 stainless steel.
• Ø 45 mm outside, 1.0 mm wall thickness.
• Straight tangents at both ends.
• Matches Spark's 45 mm straight tube, article G9002.
• Spark part number G9106, made in Mantova, Italy.

Two Ninetys or One U

Where a run has to double back, there are two ways to do it: two right angles with a straight between, or a single 180° bend. At this diameter Spark makes both, and the choice is not obvious.

The U is one part and one less joint, and its width is fixed. The pair is adjustable — the straight sets how far apart the two legs sit — at the cost of an extra weld and a slightly longer run. On a tight underseat route the U usually wins; on a build still finding its shape, the pair does.

The Tight Corner on a Large Twin

Forty-five millimetres carries a big twin on its own, and a right angle in it is normally the turn immediately after the header junction, where the run leaves the engine and heads rearward. It is the hottest bend in the system and the one with the least room.

Radius Against Space

Production tooling forms the tightest radius that will not distort the section, which at forty-five millimetres is still a substantial sweep. If a design assumes a corner turns in the space of the tube diameter, it will not — draw the arc before committing.

Where the Sliding Joint Goes

Downstream of the hottest bend, not upstream of it. Stainless grows about seventeen microns per metre per degree, and the section right after the header sees the largest swing; a joint that can slide there keeps that growth out of the welds.

Purge Time

A right angle traps air at its high point and takes longer to fill with argon than a straight. Give it more time than feels necessary — a sugared root inside a bend cannot be inspected and cannot be dressed out.

Ordering

One bend per article. Spark builds 30°, 45°, 90° and 180° at this diameter.