Y-Pipe Connectors

A Y-pipe joins two exhaust pipes into one, or splits one into two, through a single smooth junction. It can merge the two banks of a V engine or twin downpipes, or feed a dual rear section from one pipe. The universal Y-pipes, Y-pieces and Y-connectors listed here come in stainless and mild steel.

A pipe’s cross-section grows with the square of its diameter, so modest changes in size matter. Two 50.8 mm branches, for example, have more combined area than one 63.5 mm trunk. When merging, the trunk carries the flow of both branches, so it must not become the bottleneck.

The angle of the junction matters too. A shallow Y lets the two flows join with far less turbulence than a T-junction, where the streams meet head-on and push against each other.

Choose by trunk and branch sizes:

• Splits: such as 89 mm into two 76 mm branches. A 63.5 mm trunk is offered with two 63.5, 50.8 or 48 mm branches.
• Y-pieces: listed by two sizes, A and B, such as A 50.8 mm with B 41.5, 44.5 or 50.8 mm.
• Y-connectors: listed by a single size, from 50 to 76 mm, including 55, 60, 63 and 70 mm.
• Material: stainless or mild steel. Match the pipework on either side, so each joint is welded like for like.

Keep the two branch runs as close to equal length as the space allows, so each side sees similar back pressure and, on a dual exit, gives a similar sound. A Y-pipe brings three joints together in one place, so hang the system close to it and do not let the joints carry the weight. Check the clearance to the propshaft and floor, and tack all three legs before welding any of them fully, as the heat can pull the angles out of line.