Ecotec Exhaust & Airflow

Can an undercut valve stem improve Ecotec exhaust flow? Learn how exposed stem area affects airflow, why stem-to-head transition matters and how BK Racing uses undercut stem geometry as part...

How much RPM can a stock Ecotec valvetrain handle? Learn what happens to exhaust valves, springs and valvetrain control at sustained high RPM—and why circle-track racing places very different demands...

Why does exhaust valve shape affect airflow? Learn how tulip shape, back-cut, margin, stem design and transitions influence Ecotec exhaust flow—and why two valves with similar diameters can perform differently...

21-4N vs Inconel vs OEM Ecotec Exhaust Valves: Which Material Should You Run? Is Inconel automatically the best material for an Ecotec exhaust valve? No. Inconel is an exceptional high-temperature...

GM Ecotec exhaust valve size guide covering stock diameter, stem size and common L61, LAP, LE5, LE9, LSJ and LNF applications. Compare OEM and performance valve sizing and learn why...

Do performance Ecotec exhaust valves actually increase airflow? See what BK Racing learned from back-to-back flow-bench testing, including how an intentionally undersized development valve gained 3 CFM over the stock...