Racing Beat Headers for the 2001-2005 Miata (manual transmission only) are the result of exhaustive research and engineering efforts, utilizing both chassis dynamometer and road testing. Our Racing Beat headers incorporate a tuned 4-to-1 design configuration to optimize exhaust gas scavenging characteristics and power output, while improving both the exhaust note and retaining the factory catalytic converter. Hundreds of development hours and over 200 on-chassis dyno runs were used in the refinement of this header. The Racing Beat header has been design-tuned to provide measurable horsepower and torque improvements throughout he entire RPM range.
Manufactured entirely from 304-stainless steel for superior durability, this 4:1 header will offer years of enthusiastic performance driving. Our exclusive cast stainless steel engine-to-header flange features specially designed exhaust ports which transitions smoothly to the primary tubing. For the 1.8 liter Miata engine our header utilizes large diameter 1.7" OD tubing for the primary tubing, and then collects into 2.375" OD secondary tubing. All emissions control devices are retained. Each header kit comes complete with installation instructions and replacement rear gasket. The stock engine-to-header can be reused if there are no visible signs of distress or wear. If needed, replacement gasket can be ordered separately.
During the summer of 2002 we undertook a significant project to upgrade our Racing Beat Miata header line. The scope of the project was to produce a 4-1 (four into one) type header for the 1.6 liter Miata and compare it against the power characteristics of our then current 4-2-1 (Tri-Y) type header. The new prototype headers would feature a new engine-to-header flange, collector, and outlet flange. We also took the opportunity to change construction materials from mild-steel to 304-stainless steel.
With the new 4:1 header project, our initial performance objective was to retain the mid-range performance (3,000-5,000 RPM) of the then current 4-2-1 (Tri-Y) header, and improve the top-end performance (5,000-7,000 RPM) normally associated with the 4:1 type header. Under the guidance of Jim Mederer, Racing Beat's co-founder and chief engineer, initial testing on this project took place almost entirely on the chassis dyno. A rather strange looking test header was configured that allowed us to actually change the primary and/or secondary lengths while the car was strapped to the dyno. This entire assembly was suspended over the car by a specially built frame. View photos of this assembly.
Over 200 on-chassis dyno runs allowed us to determine the optimum tubing diameters and lengths for both the primary and secondary tubes. We also took the opportunity to experiment with various engine-to-header flange porting configurations and collector designs. This development allowed us to fine-tune the performance of this new header to achieve our performance requirements.
After repeated test sessions, we finally found the optimal combination that allowed us to achieve our target goal. The test results showed that the top end power of our 4:1 header had improved and the mid-range power was retained. Click here to view an article on the development of these headers and dyno results.
Header shown is for the 2001-05 Miata. Review the following Miata Header Identification Chart for the specific differences between the various Miata header configurations.