K Swap Donor Strategy: Why I Bought a Full RSX Instead of Piecing It Together

Key Learnings from FWD K Swaps

In all my research for this swap, there were some key learnings about FWD k swaps that are different from the RWD kswap i did a few years ago.

I don't already have the intended Miata transmission, shifter.

I can use stock engine harnesses of a couple different Honda varieties, I am not locked into a aftermarket third party or a custom cut and spliced adaptation.

The reality of OEM ECU hardware is that all the Kswaps of this era also desire the 02-04 RSX ECU for Hondata. The 05-06 RSX ECU and/or immobilizer are tricky(extra cost) to reflash/chip.

The motor I want comes in two different cars here in the US, the base model RSX and the "EP3" Civic Si from 2001-2005. That civic has the famous dashboard mounted shifter, so the swaps all require the more normally-located RSX shifter box, cables, etc.

The reality of my ruleset is that I need the apparently very rare 5spd transmission from these same two cars. There are plentiful 6spd options(that I am not allowed to use) on every street corner, but the 5spd is shockingly rare. Guess what percentage of base model RSXs were automatic?

Why Not Piece It Together?

Instead of trying to piece together the engine from one of two sources, the shifter, cables and ecu from a known single source, the transmission which turned out to be very hard to find, and then every random nut and bolt needed to put it together but not included by any of the 30 unique ebay resellers I would have to transact with...

The Better Move: Buy a Donor Car

I bought a donor car.

Donor Car Details

179k miles. 3 owner, grandma spec.

I've been driving it to get accustomed to the driveline, build some trust in the engine, etc. Looooooong handbrake skids in the snow, reverse J turns, etc and all just bonuses of FWD this time of year.

Next Steps

I'll be pulling the ECU to send off to Hondata during my holiday vacation and will aim to tear this apart in mid January and bolt it all into the Civic then.