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May or may not be the right sub-forum for this, but oh well.
I've been working on my first K-swap at work, with two others lining up behind it, all three are NAs. I've read up on the swap a decent amount, but I learn best by doing, so most of that information was lost by the time I started tackling the wiring yesterday. I did however, always know in the back of my mind that a dash removal is required for this swap.
This particular dash was already out for a cage install, but it dawned on me, that for NAs (maybe just NA6s), a dash removal isn't required at all. Is this common knowledge?
You can't remove the ECU harness like NBs, it's completely integrated into the chassis harness. You could remove all of your head light wiring, pull it through the firewall, and unwrap an ungodly amount of 30 year old tape and loom to pick out the ECU specific wires, but that seemed highly unnecessary for the ~3 dozen wires an NA6 has. I'll get some pictures later, but I trimmed out the TPS/IAC/PS pigtail, the ignitor pigtail, and the CAS/coil/inj/o2 harness. I'll wrap these in the OE split loom to make it pretty.
But the fan control, tach, OP gauge, coolant gauge, MIL light, and fuel pump trigger, can all be accessed at the two stock ECU plugs, or by tucking a few wires through the firewall, like the coolant and OP gauge. They also recommended a sandwich plate to utilize the early NA OP sender, but the OE Honda unit is 1/8bspt, so I just removed it and threaded in the NA unit, making a small adapter for their race harness.
*literally made an account because of this thread*
When we did my K Swap (Z3 in an NA), I think the main reason we had the dash out was because I was swapping some other parts over, and it was a convenience to do the wiring at the same time. Looking back, while it's possible to do it with the dash in, I think you'd hate yourself doing so. It takes maybe an hour to pull a dash, to save you hours of contorting your body around to run some wires.
Sure, I guess I'm thinking back to years ago, when I was going to do my first K swap in my 1 car garage. I would have been more annoyed then. And welcome.
Took some a few photos, like I said i would:
Here's the little adapter I made to go from Kmiata's harness to the OE oil pressure sender. Wire looks under tension in this photo, it's not.
Once you cut off the starter connection, you loose the battery connection to the engine bay fuse box, so I crimped them together and reloomed. I took the alternator and oil pressure wires out of this harness all the way back to the fuse box. The white cable here is the old alternator wire, which I was going to try to repurpose for the starter cable. Not sure if the main 80amp fuse will be enough, or if this "tiny" 6 gauge wire is enough.
They're not kidding about the steering rack clearance being tight. I had to grind this tiny nub off the rack, along with all the mentioned bosses and fittings. Note for NA owners, not only do you need an NB rack, but you also need the NB universal joint. I'm sure that's mentioned on M.net's NA/NB compatibility guide, but now you're seeing it here on MTgoesK.net.
@curly Bumping an old thread but haven’t found this information anywhere else and Google brought me here. First post really also, save for buying some wheels a few years ago! Here we go!
In the middle of a na6 to k24a2 swap. Using kpowers engine swap harness and kpro ecu.
How did your starter/alternator wiring shake out? Not sure I understand how the black kpower “starter relay” wire should integrate. Is it only existing to let the Honda ecu know we are cranking? Don’t see why I can’t extend the black/red factory trigger wire to the other side of the engine.
I’ve found parsing out the unused wires in the engine side makes the most sense as you said. Thank you for the tip on the oil pressure sending unit.
Thinking of drilling/tapping an 1/8bsp port in the kpower rear water neck to hold the factory Mazda sender and point up, versus at the firewall.
Also interested in your fuel line/supply solution? Haven’t made it past a new 255lph pump. Assume switching the feed for it over to the kpower provided relay is needed for the increased amp draw? (Versus using Mazda relay)
As I said, I ended up cutting the BP starter eyelet off, crimping a large splice onto the cable, and extending it to the starter. I then jumped from starter to alternator. There should be a ~100amp fuse between alternator/starter, I can't remember if I used the OE main fuse or not, I do remember pausing the think on it...next time one is back in the shop for maintenance, I'll try to remember to look and report back.
For the starter solenoid, to keep it going through the K harness, I ran the black/red OE wire into the cabin by the OE ECU location. I welded a small tab onto the trans tunnel to mount the big connector.
Look up some of the rear fill solutions on facebook and what not, bleeding these things can be one of the biggest issues. I used the NB coolant sensor, de-pinning all but the gauge wire, never had an issue with location.
As with any miata fuel pump wiring, it's typically a good idea to take the fuel pump load off the main relay, although i'm not sure if that's a problem with the K harness anymore. I did disconnect their auxiliary FP relay, and installed it back by the FP. Ground 86 or 85 where you mount it, the other goes to the OE FP power wire. 30 is fused directly to the battery, 87 goes to the fuel pump. Wire the K's ECU FP output directly to the miata's trigger wire. It keeps two relays/wiring, but keeps you from having to wire between the rear cowl and ECU, which can save some interior disassembly time.I think I'm making this sound more complicated than it is.
For plumbing, I used Radium's rail and rail mounted regulator. That gives you a port for a pressure gauge or ideally sensor too. Run the OE feed to the rail, regulator return to OE return line.
All three NA swaps have successfully hit the track for the last few years BTW, and I've since also swapped an E30 and BRZ. The other two chassis required a lot of (different) changes from K industry's kit, their exhausts seem to be the biggest issue with the BRZ, and I had to solve a number of fitment issues on the E30.
Not sure if these help. Look up AR motorsports on facebook/instagram, and look for a black NA K-swap, it was my third miata and turned out the nicest. The two red ones have OE rails, but you can see the radium rail on the E30.
BTW for anyone reading this: the BRZ is now on a stock valve cover, kept filling up the catch cans with the K-tuned one. Radium also now makes a press-in -10 fitting for the rear of the valve covers that is quite handy for these RWD swaps.
03-06-2021, 10:49 AM
NA K-swap and "required" dash removal
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