VTEC's about to kick in, yo -- my K24 Miata swap is nigh [morning repost]

Hi Oppo, it’s been a while. In May of last year I finally paid off my credit card debt and so naturally I immediately started saving for a Honda K24 swap for my Miata.

As a refresher, this is the 2002 Miata I bought myself as a college graduation present in 2012. I started entering the totally unmodified car in my local SCCA autocross events and fell in love with performance driving and racing. I’ve put almost 87k miles on it in the years since and have made some modifications to make it a bit quicker on the autocross track. I upgraded to Ohlins Road and Track DFV coilovers as the car’s first modification in August 2014, and followed that up with Flyin’ Miata’s front & rear 4-piston Wilwood Little Big Brake kit in March 2016. Those brakes necessitated upgrading to the 15x8 6UL wheels seen in the photo above. I also installed a MiataRoadster extended, angled short shifter around the same time. In Spring 2019 I added Flyin’ Miata front & rear sway bars and adjustable endlinks. The result is an extremely fun, lightweight, grippy car as you can see in the video below.

So with suspension and brakes pretty well sorted, and myself feeling pretty good about my development as a driver over the past eight years, I figured it’s time to add some more power. Most people in my situation go the forced induction route, but I really like the linear power delivery of naturally aspirated motors. Additionally, people who track their turbo Miatas tend to have a lot of cooling problems. I’m very much interested in having a reliable car I can beat on pretty much all the time. So with these points in mind, I decided to forgo a much more cost-effective turbo in favor of a Honda K24A2 engine swap.

I ordered Kmiata’s Ultimate K24A2 Swap Package back in mid-March. Over the past four months I’ve received a steady stream of packages from Kmiata and other vendors which I’ve been ordering supporting parts from. The very last piece of the puzzle, the Blackbird Fabworx NB GT3 roll bar I ordered in April, finally shipped this week! Now that I have all the parts in, I can actually start picking dates to take off of work to get this project done. The plan is to drive the car from Colorado down to my friend Justin’s place in Tennessee where he’ll help with the swap. He has access to a machine shop for whatever fabrication we might need, and more importantly he has way more experience than I do with this sort of thing. We’ll be doing some other upgrades while we’re at it, too. Here’s a rundown of the major parts for the project:

• Ultimate K24 Miata Swap Package w/ race header & flywheel
• Kmiata air conditioning kit (turning on air conditioning won’t turn the car into a snail anymore!!)
• New A/C parts (condenser, evaporator, compressor)
• Hondata Kpro4 for engine management
• Hybrid Racing K Series fuel rail
• ACT HD clutch kit (my factory clutch is definitely on its way out; perfect timing)
• Mishimoto radiator (factory radiator with 129k miles is ready for replacement; perfect timing)
• Differential arm reinforcement plates
• CarbonMiata radiator panel
• Extended stainless steel clutch line
• New clutch slave cylinder
• 3" stainless steel exhaust with Vibrant muffler & resonator, and a G-Sport GESI catalytic converter
• Innovate Motorsports MTX-L AFR gauge / MTX-D oil pressure & temperature gauge / MTX-D water temperature & battery voltage gauge
• Aluminum steering rack bushings
• 5X Racing tow hook set
  
  
• Blackbird Fabworx NB GT3 roll bar

Once I have the car back in Colorado, I’ll be deciding on seats and harnesses. Does anyone have any recommendations on reupholstering racing seats? I really can’t stand the look of black seats in a tan interior like mine. I would order a custom Status racing seat, but they’re too wide to fit well in a Miata.

I’ve seen other people who have done this swap make 220whp and extremely flat torque curves (~160 ft-lbs across the entire rev range as opposed to the Miata’s 100 ft-lbs at redline). I think I’ll be very happy to hit those numbers, as it will be doubling my current power and opening a whole new world of low-end torque. I’m very excited to finally have a sports car that will outrun SUVs and other family cars in a straight line. And with a roll bar, I’ll finally be able to start doing full track events in addition to autocross.

I’m planning to take three weeks off in August to get this done, but hoping to only need about a week and a half.