Revision 1.3 | THICKER HEAD & Collector Flanges, Counterbore holes, and sturdier collector seal
Revisions
Increased header flange thickness
Integrated counter-bore holes
Added brush finish
The original exhaust manifold in the VW 07K 2.5L 5-cylinder engine is made out of stamped sheet metal panels and therefore, its head flange is very thin, approximately 1/8”. For this reason the standard locating studs in the cylinder head are very short, sticking out of the head a bit shy of ¾”. To clear this condition and avoid the hassle of having to replace the stock studs with longer ones, the original EVOheader back in 2008 utilized a 0.250”-thick flange. This design however, required having to weld this long and thin flange without inducing warping or shrinkage. Recently, the head flange design was revised and the result is a fully CNC-machined head flange that is 50% stronger thanks to an increase in thickness (from 0.250” to 0.375”), and included counterbore holes that comfortably accommodate the short head studs and the factory recommended exhaust copper nuts (included). The flange is also given an attractive brush finish and a bevel around the edges. The new thickness and the resulting heavier weight and added rigidity also expedited the welding process. This relatively simple design change further elevates the striking appearance of the EVOheader.
In 2024, the thickness for both the laser-cut downpipe flange and collector center seal (where the primary runners meet at the exhaust collector) was also increased from 0.250” to 0.375”.
