We get behind the wheel of Ken Block’s mythical machine. A great thing about RC is that you can get behind the wheel of some of the coolest cars on the planet. OK, so it’s not the real deal, but looks the part and provides a smaller-scale version of the speed and capabilities that make these cars so cool. HPI is one of those RC companies that does a great job of taking real cars and scaling them down so that we can afford to have one in our garage, and it provides performance that will deliver a good time to everyone from beginners to experienced RC’ers. One of the latest and most anticipated scale vehicles to come out of the HPI garage is a replica of Ken Block’s Hoonicorn RTR. It’s based on the easy-to-use and efficient RS4 Sport 3 chassis, and comes out of the box ready to run. With it, you get that awesome Hoonicorn body, and underneath is a molded chassis with shaft-driven 4WD, independent suspension with oil-filled shocks, brushed motor, and more. It’s time for a little Gymkhana action, so let’s check it out!
Detailed Hoonicorn Body
HPI covered this version of the RS4 Sport 3 with a replica of Ken Block’s Hoonicorn, which is (loosely) based on a 1965 Ford Mustang. Several parts were used to get the body as accurate as possible. The front bumper and spoiler are a molded into the body, while the rear end uses a screw-on Lexan piece, which allows HPI to replicate the proper undercut of the full-size body. The rear wing and diffuser are also made of Lexan, and they too are attached using screws. An injection-molded piece was chosen to more accurately re-create the scoop and injectors jutting out of the Hoonicorn’s hood.
The RS4 Sport 3 uses a shaft-driven drivetrain to get the power to the ground, which is both efficient and durable—two desirable traits in an RTR. The entire drivetrain is sealed, so there’s no way for debris to get in and foul anything up. The top of the chassis is molded around the drivetrain components, and a cover on the bottom allows for access for any necessary maintenance. The sealed front and rear gear differentials are connected by a long steel shaft, which has bevel gears mounted directly to each end, and the spur gear is also fixed to the shaft through a molded plastic mount.
HPI spec’d rubber tires for this car, and they’re replicas of the Toyo tires used on the full-size Hoonicorn. They’re considered to be a semi slicks, and they’re molded using a durable and long-wearing rubber compound. The tires are glued to a set of fifteen52 replica wheels, which were made using the same CAD files that were used to make the full-size wheels. They’re made out of high-impact nylon, and the color was custom blended for this vehicle.
The backbone of the Hoonicorn is a unique semi tub molded plastic chassis, and this is a major departure from the plate chassis used in the past. The lower halves of the front and rear gearboxes are a part of the chassis, and tall sills in the center protect the drivetrain and also add stiffness. A cover on top gives it a clean look and works with the lower cover to keep that drivetrain clean. The battery sits on the left side of the car, and the chassis will accept a 6-cell NiMH battery or 2S LiPo out of the box, or you can remove the spacer up front and drop in a flat-style 7-cell NiMH pack.
HPI includes oil-filled shocks to damp the ride, and they feature threaded bodies and collars, so you can easily and precisely adjust the car’s ride height. The emulsion-style shocks are molded out of plastic and use dual O-rings to seal the shafts. You get four mounting positions for the top of the shocks on the towers, while the lower arms have two in front and the rear arms have three.
Adjustable Servo Saver
A servo saver isn’t usually a big deal, but the gang at HPI stepped it up and gave the RS4 Sport 3 a design that makes the car a little more user-friendly. Normally, the servo saver is a nonadjustable unit that’s built into the bellcranks, but on this car, the servo saver is attached directly to the servo, and HPI designed it to be adjustable. You can increase servo-saver strength by tightening the knurled collar on the end of the saver itself—a design that gives easy access for making adjustments.
Aluminum Motor Mount
The motor mount used on the RS4 Sport 3 is a cast-metal piece, so you know it is going to be strong and the metal will help dissipate heat from the motor, which can help extend its life. The mount itself is a clamping cam–style unit that securely holds the motor and makes for easy and precise gear-mesh adjustment. HPI even throws on a plastic cover to protect your fingers and keep debris away from the gears.
HOONICORN: The Custom ’Stang That Spawned more than 40 Million YouTube Views
Ken Block, the undisputed social media king of automotive hijinks, has 45 million views on his Gymkhana Seven video, which was the coming-out party for the Hoonicorn, the wildest 1965 Mustang of all time. Actually, there’s not much Mustang left in this tube-frame AWD beast. It was built to showcase Block’s unparalleled skills in drifting and precision car control, but apparently the 845hp 410ci Ford big block wasn’t quite wild enough for what he had in mind for his next video concept, Climbkhana. Block and his Hoonigan shop have now bolted a pair of Garrett turbos onto the thing and rigged it for methanol. The Hoonicorn V2 now makes 1400hp—enough to vaporize all four tires on demand or rocket it up America’s most famous hill climb: Pikes Peak.
Describing the V2, Block proclaimed it “the absolute most frightening thing I’ve ever driven. I’m not exaggerating. AT ALL. The motor revs and spins my Toyo tires to destruction so quickly that I can’t change the gears fast enough. It’s genuinely a mind-numbing, crazy experience to try to drive this thing. It’s amazing.” This from the guy who does terrifying car stunts for his day job!
To make sure everyone knows the V2 Hoonicorn is new and crazier than ever, Block and his team also decorated it in special reflective stars-and-stripes livery that will never be mistaken for the original black Monster Energy motif. And as pretty as the Hoonicorn is, when you see Block doing his thing on YouTube, you know the Mustang is anything but a trailer queen. If you haven’t watched Climbkhana yet, do it now and prepare to be amazed.
Behind the wheel
The Hoonicorn replica body that sits on top of the chassis is the star of the show, and I spent a lot of time checking it out before I did my testing. I am impressed with what HPI did to make this Lexan body come to life, and my favorite part is that impressive scoop that’s sticking up high above the hood. I plugged in the battery and placed the Hoonicorn on the polished floor in my garage and mashed the throttle. The tires spun as expected, letting me do a little drifting in and around objects, which is a blast. The tires have a lot of grip, so they aren’t ideal for drifting, but on the smooth concrete, they gave the car enough slip to give me a taste of it when I want to. I blasted out of the garage and onto my driveway, and I was impressed with the RS4 Sport 3’s acceleration and top speed out of the box. The included 15-turn motor moves the car along faster than I was expecting. And acceleration and top speed will increase a little more as the motor breaks in and the battery gets a few charge and discharge cycles on it. HPI spec’d a high-torque servo for this version of the RS4 Sport 3, and it showed when trying to maneuver around my driveway; steering response was quick, and the tires moved with authority. After some hot laps in the driveway, I took my Hoonicorn over to a large parking lot where I could let it stretch its legs and show me what it really has to offer. Again, the car impressed me with its acceleration out of the hole, thanks to that shaft drive. It doesn’t “feel” as fast when you have lots of room to move around, but the car reaches its top speed fairly quickly, and there’s a cool whirl coming from it as you scoot along. In the larger area, an issue with the steering came to light. I wasn’t able to get the car to track straight no matter how many times I adjusted the trim on the radio. I tightened up the servo saver, and that was all that was needed to solve the problem, making me appreciate the easy access of the adjustable servo saver. On a debris-covered surface like a public parking lot, it’s a good thing that the drivetrain is sealed—but the steering isn’t, so pebbles made their way into the steering system and bound it up from time to time, which is a bit annoying. This isn’t a big deal when bashing because you tip it upside down to get the pebbles out.
HPI nailed it. The Hoonicorn looks just like the full-size car, and it gives you a small taste of what it would be like to own the real deal. It’s one of those cars that looks great in a parking lot and is something that you’ll want to display on your shelf when you’re done driving it. This was my first experience with the RS4 Sport 3 chassis, and I really like what it has to offer. It has plenty of acceleration, and its top speed is great for a car that has a closed endbell brushed motor; the sealed drivetrain is great for those dirty parking lots that it’s going to see. HPI’s version of the Hoonicorn Mustang is all set for 1/10-scale Gymkhana