Wekfest Japan’s Biggest Surprise: A 4-Cylinder NSX

I’m going to start off this year’s coverage of Wekfest Japan in a slightly unusual way. We’ll get to the crux of this awesome event in subsequent posts, but I need to share this with you right now.

After two decades covering the Japanese tuning scene, you might understand why I don’t get too surprised these days. It’s not that there aren’t exciting things happening in Japan; it’s just that I’ve seen so much automotive craziness here that it’s almost become normal.

But every now and then something takes me aback. This is one of those times.


As I exited the Port Messe exhibition center to see what I could find in the outside section of the show, an assuming Honda NSX caught my eye.

Glancing into the engine bay as I walked past, I instantly thought someone had adapted a modern Honda plastic engine cover to fit the C-series engine for a little visual enhancement. But then I spotted some shiny piping and purple fasteners. I came to a cartoon-like stop, and turned around for a second look.


That’s when I saw the ‘Earth Dreams VTEC Turbo’ badge and realized what this could be. The owner, who was nearby, confirmed it – a K20C1 all-alloy 2.0L VTEC turbo four-cylinder engine from an FK8 Civic Type R.

This is a big deal, because anyone in their right mind wouldn’t dare mess with an NSX, right? While the C30A and C32B were decent engines, it’s often been said that the NSX’s sweet aluminum chassis deserved more performance than the tranversly-mounted, naturally aspirated V6s could ever muster, especially if Honda really wanted to compete with the European sports and supercars of the time.

Nowadays, NSXs are more expensive than ever, and the number of people modifying them has definitely declined. Most owners prefer to keep things simple and enjoy the balance of the Ayrton Senna-refined package.


But not Nakatogawa-san of S&A Auto Create. He’s the guy behind some of my favorite builds in Japan, a true technical wizard with a real eye for detail. So when a customer approached him with a stock, automatic NSX and a wish to create something special, this is what Nakatogawa-san came up with.


The K20C1 and its 6-speed manual transmission proved to be a very easy swap, as unlike most transplants Nakatogawa-san has tackled in the past, he was replacing a large engine with something far smaller.


The NSX is very much still a work in progress with many small details that still need to be completed and refined, but once it’s complete you can be sure I’ll head over to S&A Auto Create for a proper look. Nakatogawa-san told me that when it’s all done, the engine will be outputting around 450hp.


This swap makes so much sense to me. It keeps things in the family, it’s an all-alloy engine in an aluminum chassis, it’s refined, economical, has VTEC and still revs. Then there’s the turbo boost for a 100-150hp bump over the V6, not to mention the almost 200kg (440lb) weight saving from the motor/transmission assembly swap. Just think what that means for the handling and how it will feel from the driver’s seat…

Personally, I can’t fault this in any way, but I’m interested to hear what you guys think of it. If you had an NSX, would you contemplate this swap?

In the meantime, stay tuned for more Wekfest Japan 2022 coverage.

Dino Dalle Carbonare
Instagram: dino_dalle_carbonare



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Yes, a win-win all around for a street car, perfect! For a track toy I would prefer a N/A K-series, but this is a swap I can certainly agree with. However, are you sure about the 440lb difference between the auto C-series and the manual K-series?


From what I could gather, C-series w/ auto was ~700 lbs and a K-series w/ manual trans is ~400 lbs, though I'm not sure if those are both same setup (w or w/o accessories, dry vs wet,ect). thats 300 lbs, and even adding turbo and such in and 200 lbs being direct result of swap isn't far fetched. Add fuel cell, lighter exhaust, lightweight battery, ect and 400 lbs for the project is very believable


That made me stop too. That is massive, especially since the C32B is already all alloy.

Dino Dalle Carbonare

Yeah I was surprised too, that's a big number but apparently it's that much lighter. Anyway I will dive into this build in far more detail when it's all done!


This thing is next-level cool. Almost perfection.


Kyle from BoostedBoiz ran the worlds easiest 8 second pass in his K24 powered NSX, I'd say this swap is perfect.

Dino Dalle Carbonare

Totally. Been looking at auto NSXs for sale lol


love it.


Nice. Assuming it's a reversible engine swap, it should make sense to owners who want more power and are prepared to carefully store all the original parts, to preserve the car's providence.

Dino Dalle Carbonare

Yep totally reversible.


Dino, what wheels is it sitting on?

Dino Dalle Carbonare

Titan7 T-R10


Should be a norm for autos in cars like the NSX, maybe a new Japanese Law? One can argue about circuit and drag benefits from sequentials/dual clutches/etc but the whole era of the only real NSX actually fits this FK build well. Reminds of a certain few movies like Stealth where the car is the hero and has "a new, revolutionary engine" that turns out to be anti-lag turbos mated to a "jet engine" lol, what did Top Gun did to the small time producers in Hollywood back then. Paint this NSX matte black and get a martial arts master to drive it every night!

Tom Westmacott

I'm not seeing the value of this swap, personally, and it's definitely not a direction I'd go in. By chasing after 'performance' and sacrificing the NSX's biggest strengths to do so, you lose what's special about the NSX, and end up with something that's more akin to modern cars, but less good.

The C-series is a big part of what makes the NSX special - the *noise*, the revs, the throttle response. Take this out and you've just got another old car with all the downsides in terms of infotainment, refinement, safety etc.

If you want a four-pot turbo MR, you could start with an SW20 MR2, or an Alpine A110, or a Lotus Exige, all of which are smaller and lighter due to not being designed around a larger engine. Hell, you could get a new Cayman GTS 2.5T.

And if you want 400hp you could buy a Ferrari 360 for the same money, and keep the multicylinder NA howl.

Finally if you just have an auto NSX you love, well a certain Project NSX shows how to make the best of it.

The value of an older car is in its intangible charms - ripping out the biggest such charm in search of cold performance numbers makes little sense.


Sure, the old V6 would sound better than any of Honda's 4 cylinder engines, but the year is 2022 and the the NSX is probably matched in speed by any pedestrian V6 Honda Accord these days (or the last decade for that matter).

Dino Dalle Carbonare

It is indeed not for everyone out there and I totally get what you are saying. Still this sort of stuff intrigues me and I'd love to sample it for myself to see what it all feels like. I bet throttle response is shite though... The NSX-R remains one of the best cars I've every driven

peanut arbuckle

personally I have to agree with Mr. Westmacott


I think this is very subjective in what you think makes an NSX so special. For many, it's the well balanced chassis or look and though the engine sounded beautiful, their power was a letdown. It's well known that the NA C30 engines were not rockets in stock form and aren't easy or cheap to upgrade or get parts for. For people in that category, a lighter and more nimble chassis via engine swap is a win-win.

Though it would have a different feel with a small turbo K series, they're still very fast revving and responsive engines. That's why people love to swap them in various chassis. Amir Bentatou in the states has even put one in an NSX already.

I agree that this isn't for everyone, but it very much depends on how you view the car. Is the engine the soul that needs a lift, or is it the chassis and it needs a new heart to reach its potential.


Amir's street-class k20 nsx also ran a full second faster than a limited-class 720s at COTA, the chassis makes a car more than the transmission in my opinion.

Jake from State Farm

Amir's a little bitch though lol.




I have been reflecting on this idea in the past two weeks. I believe it comes down to owners wanting to experience the car as they remember it, not as it actually is.

In a world where seemingly every car has at least 300hp a 280hp car weighing over 1350kg will not seem as magical as it did in period. I believe that this drives owners to modify.

Personally, I don't care what you do with their cars so long as it brings joy. I simply ask that everyone share their treasures so that the rest of the community may have joy too.


A 200kg mass save is huge!!! That must have had a significant impact on the CoG. Did Nakatogawa-san elaborate on any potential changes needed to the chassis to take this into account?

Thanks for the cool story Dino!

Tom Westmacott

Yes it's a lot of weight (15% or so) to drop, however the C of G of the NSX is probably around the engine bay anyway, so taking weight out there likely leaves the overall balance the same, just a bit lighter.

Dino Dalle Carbonare

Yep that's exactly that the owner said. Still that's substantial, I'd imagine that will need a bit of a revision in spring and damper rates.


I'm surprised this swap isn't more of a thing, as it makes so much sense

Dino Dalle Carbonare

Should be a package some tuner offers


Impressive. The only doubt I have is the 440 lbs weight reduction as it sounds too good to believe. I used to lift weight and 440 lbs is almost 10 plates of the 45 lbs weight disk. Ask those who pump iron. 140 lbs is much more believable


Autos are heavier, plus the old Honda V6's (J series included) aren't as light as you would think they would be. They're roughly a similar weight to a GM LSx all aluminum engine.

Dino Dalle Carbonare

Yeah it does but then again the autos are heavier




As it was an Auto, it was already a crime in my eyes.

Dino Dalle Carbonare



Quite an interesting take really it reminds me of Boosted Boiz's NSX with the K24 swap
Personally I wouldn't have swapped out the engine as there's nothing wrong with the C-Series V6 but it's still pretty neat something different


If deciding things by numbers then yes the swap makes sense. A power bump and weight reduction is always nice. However, although pretty mediocre by todays standards the c30 is a lovely engine with a fantastic intake noise. I’m not sure I’ve honestly heard a better one. I’m not sure why people value power adders in combustion cars anymore, if you want a fast car just get an EV. If you want to get the engagement to the driver focus on the subtleties that only a fine tuned sports car can deliver: steering feel, shift feel, brake pedal feel, beautiful noises from the engine. For that I think going to a 4 cylinder feels like a step backwards.

Dino Dalle Carbonare

There is always the supercharger route. Fastest NSX I've ever been in had a Gruppe M blower

ashley mcbride

Seems like the perfect swap to me.


440 lb weight drop?!? Huge change to driving dynamics! I am a fan!

Dino Dalle Carbonare

Yeah, need to feel this for myself

peanut arbuckle

I mean... it's different, but I'd rather just have a stock NSX for what it's worth. This would work for people with a lot of cash on hand, but it's kinda like LS swapping a ferrari. Cool, yes, but is the application right? Well that's for the owner to decide, but I wouldn't have it.

Dino Dalle Carbonare

Is it thought? He's keeping it in the family and that goes a hell of a lot further IMO than dropping a run of the mill V8 into anything else


Well, it was only a matter of time till someone swapped the K20C1 in the NSX. Might as well since the guys at Tegiwa and RS Future have shown the way with the K20/K24 Honda powerplants.

Dino Dalle Carbonare

RS Future was a bit of an inspiration for the owner


It would be very cool if there was a build thread, but you can't have everything. Great article!

Dino Dalle Carbonare

There is, kind of. @type_yy on IG


Polarizing build. Some will like it (like me) and some obviously won't . It's not like someone took a 50+ million dollar Ferrari GTO and added K power, or made a McLaren F1 GTR electric. The swap can be reversed, the car is more fun for the owner, and the next caretaker will be free to revert her back to her original drivetrain. Thank you for covering this car, Dino. Looking forward to a more in-depth write up when you have time.

Dino Dalle Carbonare

I like it more than any other swap because it's in-house. I'm definitely looking forward to getting more time with this car


Agree on the swap, and enjoy your time with this car!


"the Ayrton Senna-refined package" - barf

The deification of Senna with relation to the NSX is a trope that can go away anytime.

Dino Dalle Carbonare

I simply hinted he was involved in fine tuning the car prior to it being finalized. I am not doing any more than that. I stated a fact, you obviously interpreted it your own way.


I did alot of work on a +800whp NSX(with the C32). The stock engine leaves ALOT to be desired imo. The 440 weight reduction seems like alot but I don't think everyone realizes just how heavy the C32 is with it's iron alternator bracket or massive castings. The K20 increases the torque and looses alot of weight so it gets alot of thumbs up from me. Sure the sound is more of a lateral move but is it really worth 3-400lbs?

At the end of the day this looks like a very clean swap and I can only assume the owner is super happy with the outcome so this is great.


HART(Honda of America's in house, volunteer racing team), built a new NSX with this same engine to go amateur racing with and it ruled as well.

Dino Dalle Carbonare

Seriously? Any link that shows it?


Next CRV diesel hybrid transplant producing 880hp mated to Bolinger dogbox. Lifted 2". Nsx safari Hokkaido Ed.


The only thing I'd like more about it if the engine bay was made to look like it was all factory, like this is what the NSX would have been if this engine existed back then. The raw aluminum looking pieces stick out. More factory looking wheels, too. That's just my preference, I really like the reasoning for the swap, as much as I prefer N/A engines over turbos.


I did expect a K series swap...just not that one haha Pretty mad


Pretty fascinating how many people in the comment section do not understand fundamental vehicle physics.

Weight > everything.