1/8-SCALE NITRO 4WD BUGGY | RTR
PHOTOS BY JOEL NAVARRO
A world champion fresh out of the box
Kyosho's new Inferno MP9 Readyset represents the upper echelon of today's competitive RTR 1/8-scale buggies, but in order to appreciate its place in RC history, you need to know first where it came from. As the class's popularity exploded at the local level, vast improvements in glow engine technology and suspension design in the early 2000s helped launch 1/8-scale nitro buggies to the forefront of RC racing. However, Kyosho was already enjoying a head start — after introducing the Inferno line of buggies in 1992, they went on an unprecedented tear of six straight IFMAR World Championships (and have won eight of the last eleven). RTR vehicles hit the scene at about the same time, and for the last decade, Kyosho's race-winning experience trickled down to the entry-level consumer with various almost-ready-to-run and full RTR versions of their most popular buggies. The MP9 Readyset is the trickest one yet, closely mimicking the TKI3 version of the MP9 that Kyosho's team drivers use in international competition, and yet Kyosho was able to turn a world-beating kit that sells for $900 into an RTR that sells for little more than half that.
Item no.: KYO31888T1B
Width: 12.1 in. (307mm)
Height: 7.1 in. (180mm)
Ground clearance: 1.1 in. (28mm)
Length: 19.3 in. (490mm)
Wheelbase: 12.8 in. (325mm)
Weight, as tested: 7 lb. 6.9 oz. (3370g)
Chassis: Stamped aluminum plate
Type: Independent H-arm suspension with upper camber link
Inboard camber link positions (F/R): 2/2
Outboard camber-link positions (F/R): 2/2
Shock positions, towers (F/R): 3/3
Shock positions, arms (F/R): 2/2
Shocks: Oil-filled coilover shocks with threaded aluminum bodies
Type/ratio: Shaft-driven, four-wheel drive/3.31:1
Spur gear/clutch bell: 46/13
Clutch: 3-shoe centrifugal clutch with aluminum shoes
Differential: Front, center, and rear oil-filled bevel gear differentials
Driveshafts: Steel CV-style front driveshafts, steel center and rear dogbones
Bearings: Metal-shielded ball bearings
WHEELS & TIRES
Wheels: Kyosho white dish wheels
Tires: Kyosho Micro Square Pin with open-cell foam inserts
Body: Kyosho pre-screened MP9 body
Transmitter: Kyosho KT-201 3-channel 2.4GHz
Receiver: Kyosho KR-200 4-channel 2.4GHz
Engine: Kyosho KE-21R .21
Steering and throttle servos: Kyosho KS-401
Battery: Four AA batteries
TEST GEAR (NOT INCLUDED)
Fuel: Byron Originals 20% RACE 2000 Gen2, quart (#3130216, $10)
Threaded preload collars on the gunmetal-anodized large-bore shocks are among the easy adjustments you can make to the MP9 to suit any running condition.
Armed with the same threaded large-bore shocks as the TKI3, minus a set of shock boots, the MP9 Ready-set's long-arm suspension is fit for both the racetrack and any terrain you'll find off the beaten path. The shock towers are stamped from 6061 aluminum, rather than machined from 7075-rated material, which helps to lower the cost of the overall buggy. Some of the near-infinite tuning options of the factory kit, like the Swiss cheese shock and camber link mounting options, were reduced in order to simplify suspension setup for the introductory racer. There's still plenty to be adjusted, however, with threaded camber and toe links, caster, and more. The suspension pivot blocks use replaceable bushings, like the TKI3, so you can alter the car's toe-in and anti-squat, and change them out when they wear. The front and rear hubs are plastic, and the steering knuckles are cast aluminum, but all three can be updated to the machined-aluminum pieces from the TKI3.
Protective boxes for the receiver and battery pack keep both vital items safe and secure. The forward-flipping fuel tank lid is accessible with the body on for quick pit stops!
If the shocks don't convince you of this buggy's pedigree, look no further than the stamped aluminum radio tray on the MP9 Readyset for proof that Kyosho's racing influence directly benefits its product line, as it's the same unit used on the TKI3. Rather than being tucked behind the receiver box like on the original MP9, the clip-secured box for the receiver battery (or AA holder, which comes with the RTR) is mounted in the right-side mud guard next to the steering servo for better weight distribution. Just a couple of years ago, Kyosho frontman Jared Tebo hand-fabricated this mod on his racecars before it was introduced in the TKI2 kit, and rather than using up old parts, Kyosho went with this new design for the Readyset. Again, using stamped 6061 aluminum in place of machined 7075 for the chassis contributed to most of the Readyset's cost savings, as the replacement Readyset chassis is less than half the price of the full-option TKI3 plate ($50 versus $120). That's a perfect example of living in affluence while spending responsibly, or what the younger crowd would call “ballin' on a budget.” Plastic chassis braces add an appropriate amount of rigidity to allow the suspension to do its job.
Kyosho's KT201 radio is light and comfortable, and the but tons on top make it simple to navigate through the adjustments displayed on the screen — it's not very big, but it's better than using analog adjustment dials!
Not only does the polished exhaust pipe look nice, but the shape of its cone is also tuned to provide a balance of power and fuel economy. Tuned pipes are often an option for most RTRs!
The MP9 Readyset sports the previous-generation TKI2 body, which looks more conservative than the radical cab-forward TKI3 lid, and beneath it is similarly high-quality equipment. Kyosho's own radio equipment is used throughout, with a digital version of the comfortable and lightweight Syncro KT-201 2.4GHz transmitter mating to the tiny KR-200 4-channel receiver, and KS-401 servos handle both steering and throttle/brake duties. Lightweight white dish wheels wrapped in aggressive “micro square pin-type” tires are bolted to the buggy's industry standard 17mm hubs, which are motivated by Kyosho's KE21R pull-start engine that breathes out of a polished and tuned exhaust pipe.
KYOSHO'S ENGINEERS SPENT CONSIDERABLE EFFORT ON CREATING DIFFERENTIALS FOR THE MP9 THAT WERE SMALLER AND LIGHTER THAN TRADITIONAL DIFFS, WHICH PUTS LESS STRAIN ON THE ENGINE AND CLUTCH WHILE OFFERING FASTER ACCELERATION
The MP9 platform's drivetrain is arranged to keep the driveshafts straight, which makes them as efficient as possible. Dogbones replace the center universals of the TKI3.
Because the strain of racing with high-powered engines is rougher than anything an RTR will likely see, MP9 Ready-set's powertrain is pulled straight from the TKI3 racecar with the simple change of using dogbones for the center and rear driveshafts (but maintaining the front universals). Kyosho's engineers spent considerable effort on creating differentials for the MP9 that were smaller and lighter than traditional diffs, which puts less strain on the engine and clutch while offering faster acceleration, and the Readyset's engine is quite thankful for that foresight! The differentials themselves are filled with oil, rather than grease like many RTRs, and the MP9's standard 3-shoe aluminum clutch is installed in place of a cheaper and simpler plastic 2-shoe setup.
TEST GEAR: BYRON RACE GEN2 FUEL
Since RC cars powered by glow engines use special fuel, rather than simple unleaded gasoline, choosing the right juice is important. Every RC fuel uses three ingredients — nitromethane, methyl alcohol (also called methanol), and oil (in varying amounts of synthetic and castor varieties) — though each fuel manufacturer has their own mixing protocols and sources. Byron Fuels offers several different fuels to suit anyone from the backyard hero to the Worlds-level racer. Since Kyosho recommends using 20% nitro in the KE21R engine, I chose RACE 2000 Gen2 for its middle-of-the-road 12% oil package, which offers a balance of power, tuning consistency, and engine protection.
BEHIND THE WHEEL
Let's get this out of the way — Kyosho's KE21R was the most impressive pull-start RTR engine I've ever used. It never took more than five pulls to fire it up for break-in, throughout the photo shoot, and during all of my testing. The carburetor was responsive to changes without constantly needing to be tweaked, and it proved to be a great match for the car's capabilities with plenty of power. After patiently breaking in the engine and tuning it to breathe fire, it lit up the tires from a standstill and left four trails of dirt in its wake; the combination of the engine's power and the aluminum clutch shoes gives the Readyset impressive acceleration that makes it easy to hop through consecutive jumps or squirt out of a rut toward the next obstacle. The engine is the heart of any racecar, and it's the defining factor of any nitro-powered RTR. Score one for the MP9 Readyset!
While 1/8-scale buggies were bred for the racetrack, they're tremendously fun to drive anywhere, but I've never been able to bring myself to go searching for the biggest trail jumps and berms with a $900+ MP9 kit. The Readyset, however, was eager to oblige my increasing curiosity and bravery. By the end of the day, I was sending the buggy over the tallest berm at our favorite Escondido park track, flying 3 to 4 feet overhead and covering at least 30 feet before smacking back to the ground — it sounds impressive, but it's not an atypical obstacle on large nitro racetracks in the U.S. The buggy sailed straight and true each time, was manageable in flight, and though it bottomed out when landing, it never got out of shape. When it was time to get on the binders, stabbing the trigger forward brought the Readyset to a controlled halt in a straight line, an indication that the front-to-rear brake bias is right on the money. The brakes were easy to modulate when entering a corner so that the fronts didn't lock up and cause the buggy to push, and once broken in, they showed very little sign of fading after plenty of hardcore testing.
Once I got the MP9 Readyset to Chula Vista RC Raceway, it was even easier to see the car's close resemblance to the full-blown racing model. Even with the stock tires I was able to immediately start clocking respectable laps, pushing the car harder as I grew more comfortable. The MP9 platform has a great mix of steering and traction, which makes carrying cornering speed easy, and the car stayed composed over the track's rougher sections. In fact, the limits of the Readyset's capabilities proved to be the included servos — rated at just 90 oz.-in. of torque with a .16-second transit time, they're perfectly fine for cruising around but not quite fast or strong enough to truly drive the car hard. They do tame the car's reactivity down, however, which will make it easier for new drivers to learn to control it before upgrading.
Reliable and powerful engine
Well-sorted chassis is equally at home on the track and trail
AA holder used for receiver power
Not-quite-powerful-enough servos dampen car's otherwise stellar performance
With so much of the RC world going toward electric power, it takes something special for a nitro RTR to stick out above the crowd — but that's exactly what Kyosho came up with when they created the MP9 Readyset. A quick perusal of the MP9 Readyset's parts list for those items indicated “MP9RS,” designating that they're exclusive to the RTR version, shows just how close this car is to full factory racing spec. While it would be cost-prohibitive to upgrade the whole car piece by piece, that potential is indicative of how much room for growth this buggy has — it is, after all, based on a World Champion.