Four years ago I viewed a HyTech header that set the standard for any header comparison in my mind. HyTech was too busy to develop a MINI specific model so I gave up on them. A few years later Bob (SpiderX) shows a photo of a custom built header that has the features I’ve been looking for. I kept that picture in the back of my head until I was ready, and as fate would have it, custom fabricator Juston Poole (404-625-1882) was also ready, with tested prototypes and units in use, plus a willingness to begin production.
I muck with the established working design and Juston is accommodating; my ideas cause at least one installation issue and my propensity for jinxing products causes more install hic-ups, but the important part is what works, and this header works. Notice the unique sequential cylinder pairing taking advantage of the MINI’s unique firing order.
D-shaped flange ports with correctly centered primaries, unlike some other headers I've seen.
The workmanship is outstanding. Although merge angles are not critical for the MCS, added effort has been applied to the merging collectors on this build.
An extra bung for wide band use is a part of this package. I’ll let Juston speak for the importance of throat diameters; a venturi can also be seen here.
A high flow cat and V-band flange.
The lengthened primary and secondary tubes require moving the pre-cat O2 sensor down about six inches. Cutting the upper engine harness wire sheath frees up an extra 7.5 inches of sensor wire length.
The header heat shield needed massaging and trimming to fit the header’s power hump shape. Heavy handed work with a hammer caused small cracks to grow into larger ones. Holes drilled at the end of the cracks stops them from going further, straps help support the shield preventing further stress, and assist maintaining space above the primary tubes.
My request for an accordion style flex section increased overall length from the original design.
Had I been aware of the ramifications, I would have done a few things differently like having V-band flanges on the end of the cat and on a transition section, but one must move on to things one has control over. To fit the OEM cat back, a section of the exhaust’s pipe is cut out and a coupler used.
On the road the effect on performance was/is noticeable. From 3,600 rpm torque was pronounced and the motor really came on the pipe above 4,000 rpm all the way to the top. However, anything below 2,000 was flat dead, fortunately that only effected school zones and stop light-to-stop light situations. The power delivery reminded me of a motorcycle motor I had built by a drag racing shop; apply throttle, pause, then, bam. As a side benefit, the exhaust’s sound was wonderfully rich and round like a larger displacement motor; I loved the idle note (and still do).
After living with the header for a while, I realized a resonator was needed. It wasn’t full throttle under load that was bothersome; it was a 2,300 rpm angry buzz. Also, a secondary resonance hovered around the 2,800 rpm area; the hopeful solution, Flowmaster Hushpower II.
After installing, the entire power and driving experience changed. I am so pleased with what that short resonator provided. Power delivery returned to a linear state and the motor
gained low-end torque. Part of the power return may be from improving transitional diameters, but I also believe there is some real magic in that Flowmaster piece. The offending resonance wasn’t eliminated, but it sounds off in the distance now rather than engulfing the cabin and the noise duration is clipped short.
I’ve been counseled in the past about the importance of a properly designed header in extracting the most out of a modified head (Endyn’s in my case), and I minimized its role, because after all the OEM part performs adequately.
I am now
a believer.
