914 WRX Build Options

[waltonsm]

After seeing some recent posts, I decided it was finally time to thank everybody on this forum for years of encouragement and scope creep on my long term project. As with every real project, this will never be done, and there are certainly many things I would do differently a second time around. But I am 80% of the way there, and I am enjoying driving it as much as I am working on it for the last year or so.

I plan to add more photos of my build process over the next few weeks. You may see some of the advice you gave me realized, and probably some bad or good ideas in metal, fiberglass, and wood.

Hopefully I can help someone else out too.

-Steve


Here are some recent photos:





And a few from about 4 years ago:

[waltonsm]

While waiting for transmission parts I decided to revisit a backburner project. Now that I will have tires that are capable of below freezing temperatures, I need to actually get a heater core in the car. The heated seats, down blanket, and fur hat work OK, but don't do much for defrosting and keeping the feet warm.

I started this project a couple of years ago, but it stalled several times because I was overthinking it while retaining the option for A/C. Odds are low that will happen, and I will learn from this project anyway.

I set off to find the smallest heater core of the right form factor and outlet configuration that I could buy. So many of the tiny ones have odd plumbing routing to fit in tiny dashboards (e.g. suzuki samurai). I ended up with a mid 90s mazda 626 core.



The airbox fits in a pretty small space, and I was planning on retaining all the original controls for the fan, heat, and flow directions from the dash, along with the drains and existing plumbing. The only thing removed is the original intake lines from the exhaust heat exchangers. I maintained filtering, water trap, and drains with this design and it is serviceable, about as serviceable as the original design once you get the tank out. At least I have a top exit fuel pump now.

I also needed to add a heater control valve inline with the heater core to ensure I can still turn it off when I don't want it.



The whole thing fit together pretty well. I might do it slightly differently a second time. but electric shears, abs sheet, and abs cement worked great for this project.



Then came the wiring... I had forgotten about my prior plan to make this work, but happened to have all of the parts on hand. The 914 switches the resistor grounds in the oem fan airbox using the slider controls on the dash. Most modern stuff switches the resistors on the hot side, if it has resistors at all. The SPAL fan I bought does indeed have resistors, and I needed to switch the hot.

After figure out which pins are what, I bundled up a harness packed with relays to convert the switched ground to switched hot. Maybe someone here will find these numbers and sketch useful. I ended up using my $50 wifi/cellphone borescope to pick out wiring colors under the dash (because I had already cut the harness near the fan)
I did test this harness before bundling everything up, so of course this is the time I got it right on the first try.