Artec TD04 Cast Exhaust Manifold RA

The biggest flaw on the factory manifold is only 3 runners reaching the collector even though its a 4 cylinder. 2 runners were merging just before the tight radius in the turbo flange area. the cracks were appearing along where the y runner met the other 2 runners. This is because twice the hot air flows in the same diameter pipe, resulting the runner with a much greater hot spot which causes it to expand more. So where it was cracking is where the metal is moving the greatest amount.

So when ARTEC were designing this manifold, they removed the particular hot spot by removing the restriction and/or bottle neck caused by the tight radius’ to increase flow. Made from 347 Stainless Steel, the runners have an inner diameter of 33mm, this combined with the longer radius’ keeps response up by reducing manifold volume, but also keep flow up.