Evo 8.5 - Donor Parts

As it always seems I start projects figuring that I'll need this cute little list of parts. In the end the list always grows. This one is no different, although the basic swap is fairly simple.

Here is the list of parts (as I presently know it) needed to swap a 2006 Evo IX motor into a 2003 Evo VIII.

- Evo IX longblock

- Evo IX ECU

- Evo IX complete engine wiring harness

- 2nd Relay on firewall (next to ABS module)

- Evo IX 5spd trans harness

- Evo IX rear (secondary) O2 sensor

- Evo IX Lower Radiator Hose or Cut Evo VIII Hose

You'll also need engine oil, trans fluid, TC fluid, coolant, etc.

Here's a few notes on some of these parts:

Evo IX longblock, my donor is throttle body to turbo outlet, I did this for two reasons. 1st was to make it easier, 2nd was to comply with SCCA SP UD/BD rules (although I only needed the longblock and turbo, not the manifolds)

Evo IX ECU is obviously programmed and wired for the addition of MIVEC. It also has 3 plugs in comparison to the evo VIII ecu that has 4 plugs.

Evo IX engine wiring harness, this is necessary because of the addition of the MIVEC wiring and the aforementioned 3 plug vs 4 plug. The addition of MIVEC adds an extra plug for the intake cam CAS, OCV solenoid & extra firewall relay. There are also 6 more plugs for the ACD wiring, but thats of no consequence here as the VIII has all mechanical diffs. One other note, the donor for this build was in a front end collision. As such the ACD plugs were destroyed and there may be other damage in one portion of the harness. I'll be cutting back the loom and inspecting those parts of the harness to try and avoid any issues.

2nd relay on the firewall, pretty sure this is for the MIVEC, but not really sure. Edit: Adam has confirmed this is for the MIVEC.

EVO IX 5spd trans harness, this is a small harness for the reverse switch and speedo sensor. Mitsu saw fit to change the plug where it connects to the main engine harness. This one was a surprise for me. Luckily I found a used one for $40, dealer pricing is $90+. Edit: You can also cut the plug off your 8 harness and rewire. Personally I prefer the reliability of the OEM harness, so I try and keep it stock where possible.

EVO IX rear O2 sensor, this one was also a surprise. If I can't find a used harness I'll probably use a weatherpack connector. If the sensor ever needs to be replaced I won't be paying for an OEM one anyway. Edit: Like the trans harness this can be re-wired, but it would be nicer to have the OEM harness plugs.

Thats all I've got for now. If anything else comes up it'll get added to this post.

J