PDI’s Big Boss diesel exhaust manifold undergoes abrasive flow machining

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Engine block cylinder honing is a fairly straight-forward and decades-old practice that hasn’t required a lot of advancements through the years. Shops and garages across the country have peg boards filled with hones.

However, when it comes to removing imperfections and enhancing the performance of exhaust manifolds, the twists and turns of these passageways, many of which feature oblong paths, can really benefit from much more sophisticated machining.

Enter Extrude Hone. The Pennsylvania-based company pumps a thick, putty-like material containing silicone carbide through the exhaust manifold at a high-pressure in a process called abrasive flow machining. (Cylinder hones also use silicone carbide as an abrasive media).

“As it flows through the insides of the manifold it is smoothing out all porosity and giving them the absolute best, smooth finish,” Performance Diesel Inc. (PDI) events manager Lance Brown explains in the video below.

Extrude’s work on PDI’s Big Boss Exhaust manifolds not only produces maximum exhaust flow, it also removes imperfections that can lead to increased heat retention. PDI reports a 20 percent gain in air flow over stock and an exhaust temperature drop between 75 and 100 degrees.

Port analysis and testing further ensures a balanced flow to the turbocharger for greater boost and the potential for increased fuel economy.

If you like machining like we do, watch Brown on the rest of his tour at Extrude Hone. While you may not be able to add abrasive flowing to your tool line-up, the next best thing is watching it at Extrude.