09/10/2026
A look back to one of our late nights last August, when we finally put the Black Miata on the dyno to find out how much power it made.
The idea behind the engine was simple: what happens when you take the Maruha Motors catalog for the B6 and build the engine as a complete package? The result is no longer quite a 1.6L. With the 80.5mm bore, the B6 becomes a 1.7L, using Maruha's custom MAHLE pistons developed specifically for the B6. With an 11.0:1 compression ratio, the piston was designed to be equally at home on the street or in a more heavily tuned application. Rather than chasing a collection of unrelated parts, we followed the Maruha recipe from beginning to end.
**The build:**
• Maruha 80.5mm MAHLE pistons — 11.0:1 compression
• Maruha connecting rods
• Maruha 1mm oversized valves
• Maruha F cams
• Maruha ITBs for B6
• Maruha 1mm oversized valves
• Maruha bearings, shims, lifters
• Maruha Freedom ECU
• Maxim Works header
• Maruha x Yoshimura Exhaust
The engine was assembled using the knowledge and experience gained through our time working with Maruha in Japan. There is a certain philosophy behind the way these parts are designed to work together, and this engine was built with that in mind.
Then came the moment of truth: 177.6 WHP.
The number itself was better than we expected, but what stayed with us was the way the engine arrived at it. We made more than ten back-to-back pulls, with and without the funnel socks on and the results remained remarkably consistent. The engine repeatedly produced more than 170+ WHP, with a power curve that traced an unusually clean, almost straight line across the run. There was no dramatic peak or sudden change in character — just a compact 1.7L B6 breathing through four individual throttles and continuing to pull as the revs climbed to 7800rpm. After ~5,000 km of break-in, it was satisfying to finally see the character of the engine translated into a graph.
A fortunate few got to experience this car on track at the 2024 Miata Reunion, something that the dyno could not describe. The sound, response, and character of a properly built Maruha ITB Miata.
