- DHM 13.4:1 High Compression Piston
- DHM Stage 3 ECU Flash
- TB Parts Camshaft (can be purchased without if you already own one)
- NGK CR9E Spark Plug
- Spark Plug Spacer
Combined with your aftermarket intake and exhaust, this is the most you can get out of your Grom / Monkey without doing any head work. After dyno testing we were repeatedly seeing 13.5hp at the wheels (SAE) run after run! The Stage 3 package makes more power than a stock Grom at every RPM and double the horsepower at 9000+ rpm! 91 octane fuel is absolutely required. Any fuel with a lower octane rating may result in engine damage!
*Requires ECU to be mailed in for flashing services