Originally Posted by Hebertbrendon
I swapped a k24a2 into my 06 rsx, and it ran and drove fine. I recently did a full rebuild and ssaw someone say not to do it without a kpro. Why is that?
Because the factory tune can't safely run the motor. It may be able to run, but I guarantee it's not safe. Most get a CEL for running too lean. Even if it could run it safely, you're not taking advantage of the motors full potential.
the K24a2 has a lower compression ratio, lower redline, larger bore, and longer stroke. Do yourself a favor and get Kpro. That is the best way to protect your investment.