Got about 200 miles on the new piston so far. It seems slightly better on the bottom end where it had lost some due to the tb cam. Overall it feels better still not a powerhouse but noticeable.
10/10 recommend doing. This is how Groms should come from the factory!!!
Looove the stage 3 kit. More rpm and definitely more mid range power!!!
do not be hesitant about this, it is by far worth the money and david is great to work with. the power difference is awesome, install is a breeze. hit the order now button asap
Fun project to do on a grom! Perfect for someone who wants some engine experience and more power! Completely brought back the low end I was missing from the cam. More than worth the price!
This is the Upgrade kit for existing DHM customers! You MUST send in your previously flashed DHM ecu. If you send in a virgin ECU you will be charged at the full kit price, not the upgrade price. If you do not already own a DHM Stage 1 flash or cam package, do not order from this page. You can order a complete kit HERE.
The DH Motoring Stage 3 Package consists of the following:
DHM ECU Flash
DHM High Compression Stock Bore Piston
TB Parts Camshaft
NGK CR9E with spacer
Combined with your aftermarket intake and exhaust, this is the most you can get out of your Grom 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!
We are not selling preflashed cores as part of upgrade packages. You must send yours in to be updated. This is subject to change, but at the moment there will be no exceptions to this.