1. LENGTH COMPARISON TEST
The equal length shows smooth torque results mid rage and the unequal length shows more power up high in the power band. The equal length also delivers a much better race engine sound. The unequal length shows room for power gains up top with more R&D.
2. OPTIMUM DISTANCE TO MERGE SECTION
The 3 Test Stages of finding the optimum distance to the merge section.
(1) Comparison of 370mm and 620mm
The 620mm length design showed the power band peaked around the 4000 RPM area.
(2) Comparison of 90mm, 240mm and 370mm
The shorter 90mm and 240mm showed the power decrease before the 6000 RPM range.
* From the various test results obtained we decided with the 450mm length which is in between the 370mm~ 620mm area.
(3) Additional tests was done with length ranges between 370mm to 620mm at 400,450. 500 & 550mm sizes to find any extra gains.
From the additional extensive testing we found the 450mm delivered the best results.
3. PIPE DIAMETER & MERGE SECTION
Increasing the exhaust pipe diameter is will increase performance gains but too large will cause power loss. We found after numerous tests that the φ42.7mm size made best results.
These test results showhow we tested and why we chose the exhaust manifold product designs of equal length φ42.7mm L=450mm.