I am not so sure… The -real- difference between a microcontroller and a single Board Computer (SBC) is really the scheduler to get to real-time operations. The SBCs can usually do orders of magnitude more processing, however, it is really how the processing is scheduled is what makes a microcontroller tick.
It runs in a lockstep fashion so it is -really- consistant. The SBC has a lazier scheduler, so it isn’t really guaranteed to be consistent to the millisecond or less.
Now if you can find something like FreeRTOS or another real time operating system, that changes the scheduler which then works in a lockstep fashion then you shouldn’t have any issues. But you probably aren’t going to find a free RTOS to run on it. The Odroid uses a Exynos chip, which has very minimal linux support because they sparsley released documentation or patches for the linux kernel.
That being said, it may or may not work without a RTOS. I wouldn’t try it without a rtos on an engine I cared about. FreeRTOS has some support for the RaspberryPi, I don’t know about the pi2. It -should- work for that, but I would see if someone tried it already.
DIYEFI.org is probably where I would look. The use a Freescale MC9S12XDP512 microcontroller.
Instead of getting an Arduino, I would probably get a teensy 3.1 board. You can use the Arduino sketch system, but the teensy appears to be a far superior microcontoller for 20 bucks. it has a 72mhz processor instead of the 16mhz my arduino has, and it has like 4x more ram, storage, etc as well too.