Vehicle exhaust systems

A balance pipe assembly for a vehicle exhaust system comprising

• at least a pair of exhaust pipes or pipe shaped portions,
• a further pipe or pipe shaped portion extending between the exhaust pipes or pipe shaped portions so as to act as a balance pipe, at least one of the exhaust pipes or pipe shaped portions comprising means adapted to reduce the pressure of exhaust gasses passing there through at a position downstream of the balance pipe or pipe shaped portion, and
• a pipe or pipe shaped portion that is adapted to promote the swirling of exhaust gases passing there through,
• wherein each of the exhaust pipes or pipe shaped portions comprises a portion that is adapted to promote the swirling of exhaust gases passing there through,
• wherein the pipe or pipe shaped portion that is adapted to promote swirling of exhaust gas passing there through is located at a position downstream of the venture,
• wherein the or each pipe or pipe shaped portion that is adapted to promote swirling commences at or near the venturi and progressively opens up in a downstream direction until the pipe or pipe shaped portion once again has substantially the same diameter downstream of the venturi as it did upstream of it, and
• wherein the or each portion that is adapted to promote the swirling of exhaust gas passing there through comprises a swirled groove formed into the wall thereof.