Feature: Midship Runabout – Kyon’s Impact! K24R MR-S

Hailing from the Kansai region of Japan, Kyon has spent years chipping away at his lap times at Okayama Circuit, his local course.  His accumulated experience at the circuit has garnered him a personal best of 1’39.6 at Okayama, a respectable time for his MR-S.  For the first time ever, Kyon chose this season to take his build to Tsukuba to see how he would compare around the proving grounds of TC2000.

Over the past several years visiting race tracks around Japan, I had gotten used to seeing the wide range of tuned MR-S builds from Techno Pro Spirit in the paddocks.  It would be rare to see these mid-engine cars with support shops other than TPS, and even more rare to see them with engines other than the 1 or 2ZZ.  So you can imagine my intrigue when I first saw Kyon’s build parked in one of the Tsukuba garages upon my arrival to the Zummy Racing event mid-January of this year.

It had rained over night in the Gunma area and the still saturated asphalt of TC2000 cast a dark foreground across the paddock.  With the overcast skies throttling the early sunlight, the black, carbon-clad MR-S seemed to have been cast straight out of the ground, blending almost seamlessly into the blacktop.  Equipped with a Trial GT Widebody, the wide 5-lug TE37V rear wheels, the solid chassis mounted rear wing; it was a menacing build that fit right in with the most serious of Attack cars in the paddock.

Upon further inspection, and some brief conversation with the owner, most of the car was built by Kyon himself.  The Reckless GT Widebody kit, originally made by Trial, had been remade in carbon fiber with some additional modifications to the overall look.  The hood, with it’s single drop vent, and the rear skirt extensions were both made by Kyon with a spread-tow weave style carbon.  The rear engine cover and kevlar headlight covers were also DIY pieces.  These parts, along with the Project K carbon top and extensive interior weight reduction, bring the car’s overall weight down to a mere 950kg – just over 2000 pounds.

 

Heading back into the paddock from a still wet session, you can get a glimpse of the air hose input, hinting at the installation of air jacks.  With the car’s current aero package, which consists mostly of Kyon’s own building, has helped him get through his first season at Tsukuba with a fastest lap of 58.916.  The Garage BB Forte 3D GT wing has been frame mounted with homemade solid mounts, along with the carbon diffuser.  With the assistance of Under Suzuki, the two will be working on improving the front aero for next season.  In fact, after this track event, Kyon ended up going to dinner with the Suzuki brothers – no doubt a lot of new ideas were running through his head by the end of the night.  It’s possible we may get to see a more refined setup in the future.

When we introduced this car on our Instagram page, I mentioned that it was a little rough around the edges.  It was difficult to see in the smaller images on the app, but maybe you can now get an idea of what I meant.

 

Heading out for the first session of the day, I was excited to hear the car wide open down the front straight; although the track was still wet, and I knew they wouldn’t be driving at 100%.

 

The MR-S use a one-off harmonic drive set of Spirit built dampers.  Hyperco springs (6k front/8k rear) assist the car around corners.  The bushings in the rear arms have been swapped to full sphericals, and the car is equipped with front and rear Cusco reinforced stabilizers.

 

 

On track, the car sounded very much like a Honda.  If you weren’t looking, you’d easily expect their to be an EK9 or FD2 out on track.  That may be an obvious statement, as this car is equipped with a K24R engine.

 

The MR-S uses a staggered wheel and tire setup.  Previously on a full set of TE37V (16 front/17 rear) with 20mm spacers at all four corners to fill the widebody,  the setup was changed for this season.  Now, the fronts were a pair of 17×8 +35 Hethel Toybox 48 wheels, more commonly found on the rear of Lotus Exige’s, are wrapped in 255/40/17 Advan A050.  The rear were still TE37V, however now a much wider 18″ size with 295 series A050’s, a major improvement in rear grip.

 

The exposed width of the 295 Advan A050 gives an intimidating look from this angle.

 

The rear 5-lug conversion was pieced together using the front hubs from a ZZT Celica (5×100 PCD).  Kyon says that since the hub bearing is the same as the MR-S, it is almost a bolt-on conversion.  He opted to have the rear brake hats (which have been converted to a two-piece setup by BIOT) custom drilled to 5×100 instead of sourcing a new rear kit.  BIOT is a shop in Tokyo that specializes in making 2-piece rotor kits in custom sizing.

 

From this angle you can see how Kyon integrated the wing stays to double as a diffuser mount.

 

With the rear cover off, we can get a glimpse at the K series engine tucked away behind the firewall.

 

 

The K24R was built by Kyoto based engine shop Impact! – a shop that’s garnered quite a bit of attention recently in the time attack scene with their high-powered, reliable NA Honda builds (Sougo’s Orangeball DC5 K series is also built by Impact!).  The engine puts out a healthy 300ps utilizing TODA 4 throttle intake manifold and most recently the addition of TODA VTEC Killer (A3) camshafts.  You can read more on the build, and the deletion of VTEC on Impact!’s blog post here.  Further modifications include TODA reinforced valve springs, and a titanium exhaust.  TRD engine mounts hold the new motor in place securely.  The transmission was sourced from an Integra Type R and is equipped with an Exedy hyper single clutch and ATS LSD.  The MR-S is tuned with a Hondata K-Pro.

 

The Endless front brake kit peeking out behind the Hethel wheels.  Due to the wet conditions, every driver had been overly cautious on track.  Rightly so, one small slip up could end the season for these guys.  Kyon compared his first wet laps to Shibata’s laps in the Arvou S2000 and calculated he was about 10 seconds off pace due to the conditions.  This event was his first ever run at Tsukuba, outside of a simulation.  Luckily the weather improved the next day and he was able to get a better idea of what he was capable of at the track.  You can get a look at his fastest dry laps in this video here.

 

While the focus was placed on Tsukuba this season, in prior years, Kyon has driven a variety of other circuits including Fuji Speedway, Suzuka, Okayama, and several other circuits.

 

Kyon updates his personal Minkara blog often – we’ll be sure to check in throughout the off season to see the progress continue on this build.  Looking forward to seeing this car in person again next year!