On the surface, gaining 8hp doesn’t sound impressive until you realize that is a 13% increase in power. 13%! It gets even better with torque as the 17 lb-ft we added is a 31% increase. You can feel this gain driving too as the car pulls a lot harder up to 6,000 RPM. We also found the Cappuccino was able to induce more wheelspin when autocrossing. Factor in the drivetrain losses and we’re making about 80hp at the crank. In a 1,500 lb car that is pretty damn good.
There are turbocharger upgrades available for this engine that can carry boost all the way to redline and give us over 100 hp but this would require a strengthened bottom end and larger fuel injectors. Triple digit horsepower can also break the gearbox and differential. These are both outcomes we would like to avoid! While the Kei Sport USA ECU can support these higher powered builds the provided tune is developed around factory injectors so the map will need to be modified accordingly. EDIT: Kei Sport USA has released a new tune built around 450cc Deatschwerks injectors. This new tune will allow Cappuccino owners to harness the full capability of larger turbochargers with less risk to their engines.
We performed a pull with stock boost and Kei Sport USA’s provided tune. Brad was impressed with how well developed the tune was; the only change we made was a tweak to idle fueling to prevent the Capp from stalling when coming back to idle. Our Cappuccino has a failing IACV so this may not be necessary for other owners. Installing the ECU with no other changes was good for 4hp and 15 lb-ft on its own. Even with more boost Brad did very little actual tuning: Kei Sport USA’s VE tables and ignition curve were great right out of the box. Considering the price, the ease of installation, and the headroom it provides, the Kei Sport USA PNP ECU is an upgrade all Cappuccino owners should consider. Kei Sport USA is currently working on a PNP for the Honda Beat and is a registered distributor of Fujitsubo exhaust systems. I want to give a huge thank you to Jeffrey Burdick at Kei Sport USA as he provided a ton of tips and feedback to get our car up and running with its brand new brain.
3 comments
Time for a diff and sticky cheater tires for the cones!
Great writeup! Really looking forward to the Shorai battery details! looks like they have a size perfect for my NA6 Miata
Here’s an old MotoIQ article that discusses the basics of engine management systems:
https://motoiq.com/basic-control-systems/