K-swap How-to: A by-the-book K24A2 NB2 swap build thread
 

I have been trying to get my hands on a K-swap project for about 18 months now. The combination of Miata chassis dynamics and N/A K24 power is too cool to not love, even for a boostaholic like me. I've had too much going on to buy a chassis and build one myself, but I was able to convince a good friend of mine to do it instead.

Emilio did a good job of documenting his buildup, but he went well off the beaten path. Cool build from a technical standpoint but minimal relevance to anyone trying to actuall build a car for themselves. This build will be a bit more conventional and relevant. Kmiata swap kit, 2006 K24A2 longblock, off-the-shelf intake/exhaust parts, built mostly as a daily driver. The donor is a clean 130k mile NB2 Sport car, so the 6-speed and Sport brakes are already in place.

Poor thing will never know what hit it.

Attachment 231915

David from K-Miata and John from Inertialab are out this weekend assisting with the buildup. David will be cutting an instructional video that goes into more detail, but this thread should be a good resource for customers who are looking for some help or potential customers who want to understand what they're getting into.

The donor car is a 2002 Sport package car without ABS. The 01-02s are the sweet spot for the NBs, since you get all the benefits of the NB2 (nicer interior) without having to deal with the T-F diffs. In addition to the K24, the car will get 700/400 Gen2 XIDAs, a Blackbird Fabworx bar, 15x9 6ULs, and a bunch of other upgrades to support the new powerplant. More on the extra upgrades once the engine is in the car.

First step is pretty straightforward - drop all the stock stuff out. We dropped the engine, trans, front subframe, and all the suspension together.

Attachment 231916

In addition to the complete engine/trans/subframe removal, you’ll also need to remove your dashboard and HVAC components in order to install the Honda wiring harness and connect it up to the Miata dash harness.

Attachment 231917

I’ll have another post or two tonight detailing the engine preparations and the swap kit parts (mounts,subframe, adapter, flywheel, etc).

Good to see this on here, i have seen David posting stuff on social media. Your not gonna want to play with Miata motors any more.

Nice. Will be following.

I'm going to let the cat out of the bag. (No animal abuse to feline on sensitive to cats Miata forum...simply acronym.). I'm going the K swap route.
2 things are going to happen to the future of this forum:
1) people are going to run Honda motors and enjoy their cars.
2) people are going to get amazing deals on part outs from members ditching their turbo setups to go K swap.

Either way, miatas for the win!

Yeah I'm in denial at this point. With Dave and Kmiata being so close to home for me it's becoming a no brainer. I've been building up parts for an N/A build now and to go turbo again down the road but theres a small part of me in the back of my head that keeps screaming "WHY ARE YOU BOTHERING JUST SELL ALL OF IT AND K SWAP"

Yeah, you've said lots of things and done nothing.
Move along and don't clutter up his thread.

One of the things we were able to do was take an extremely accurate weight of the K24 vs the factory engine, including all the auxiliary components that are included with the swap (subframe, flywheel, header, etc). I'm curious to see what you guys think the weight difference is before I say, though. Thoughts?

Attachment 231913

Attachment 231914

15 pounds heavier.

15lbs lighter. Subframe has gotta be a net saver, maybe the K24 block too.

22 pounds lighter Bob

i remember readying in their thread that it saved 50lbs, but who knows how accurate that is.

Awesome thread. 32 pounds lighter WAG.

I'm betting the engine itself is 35-40 lbs lighter, the subframe is probably 10lbs lighter than the stock one. I'm betting the rest of it is a wash.

The kicker will be how it was weighed. The k swap can not run a/c or p/s. So was the the BP weighed with the accessories?

How much of a pain in the nuts was it to pull the dash out and do the wiring?

-35lbs, all in. BTW, I know you have SWAG Andrew so I think you need to kick down at least a cool Trackspeed sticker for the right answer. :)

@asmasm is gonna bust a nut if you properly weigh it all and document.

If you are swapping a NB the wiring is very straight forward and not to difficult, NA is another story.

This is very true. There is so much bad information on engine swap weights because accessories can weigh 80+lb and people don't specify what is on the engines when they weigh them. Andrew, I have an 1100lb hanging scale I can lend you if you want something easy to weigh with. I think engines weights for swaps should get compared without clutch/flywheel, exhaust, AC, or PS- But everything else.

From all the weights I have read online I pieced together an estimate that the actual weight of a k24 is about 25lb less than a BP when its dressed the same. That is pretty impressive when you consider one engine is .6l larger displacement and makes about double the horsepower with stockish internals.

The k series swaps are pretty damn awesome, I might have even gone with it if it had been more popular when I first started planning for an ls. I'm guessing about 30#, and I can confirm the bad information about engine swap weights. A lot of the guys try to act like adding a v8 to the car doesn't add weight by saying the bp is super heavy. I've heard some pretty wild weights throw around in the v8 community, hell if you'll let them, they might even convince you that the bp used a tungsten block. I just comfort myself by saying a turbo would have added some weight too.