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This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game
BY Wes Taylor //
April 6, 2021
@lock_it_in_productions
Ethan Mitchell
ethan_mitchell19

  • USAC Midget dirt racing sees vehicle entrants weighing under 1,000 pounds.
  • With no transmission, the cars are push-started by support vehicles before the race.
  • This Bundy Built entry utilizes an uncommon 380hp 4Piston-modified Honda K24 engine that screams to 9800rpms for almost the entire race’s duration.

When I got contacted about shooting a feature I knew nothing about, I became hesitant at first. I’ve never been to a dirt track event, nor have I explored the world of the cars involved in it. After some time spent with Ethan Mitchell and his dad John in their shop, I learned what it takes to be on top in the Midget car community. Essentially they’re big go-karts, which is how Ethan got his start about six years ago.

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

THE BACKSTORY

Ethan came from Tennessee to visit his dad one summer. Upon meeting some friends, he hopped in the driver’s seat of a dirt track car and fell in love; that’s when they decided to prepare a kart of their own. The idea of building a Midget car is relatively simple but actually quite intricate in its build process. First, you contact the chassis builder of your own choice. Once the chassis comes, the tedious task of sourcing all the parts for the build starts. Most of the more significant components, like the motor, are more accessible; Ethan explains it’s all the little things that add up and are harder to find.

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

BUILDING IT UP

The team decided to use a solution from Spike Chassis, which is a popular choice among the Midget car competitors. The 72-inch wheelbase frame comes strong, made of 4130 Chromoly tubing while maintaining a lighter weight. Most of the field runs the same suspension setup as Mitchell, but the Bundy Built team have a few tricks. The front axle uses a Panhard bar setup, with DMI spindles suspended by Factory Kahne twin-tube shocks with Draco Racing springs. What makes the Mitchells’ Midget stand out from the others is that they’re using coilovers in the rear; most seem to stick to bars. Gas Factory Kahne shocks wrapped by Draco springs keep the back planted while a Ti Jacobs Ladder bar controls it.

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

THE GROUNDWORK

Braking comes from a 10-inch Ultra Lite system both front and rear, while a Wilwood master cylinder helps fluid to all corners. The kart rides on 31-spline Keizer Midget wheels all around. With 13×8-inch up front, the rear setup is quite different than what people might think. On the left is a 13×10-inch wheel, but on the right sits a 13×12-inch. Most of the force gets put on that right rear which makes sense, and Hoosier produces a unique midget dirt track tire, just for this type of racing.

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

2.4-LITERS OF SCREAMING FURY

My favorite part of the kart is the drivetrain; they all use naturally aspirated four-cylinder engines, and Ethan gets all he can get out of his. Ethan decided to use a Honda K-series engine as a base and built it up from there with high-end aftermarket parts — and surprisingly, some stock ones. A stock 2.4-liter K24 block had some machine work to enlarge the factory 87mm bore to 90mm, leaving some paper-thin bore walls. Factory-length Carillo rods attach to a stock 99mm crank, while custom JE Pistons, supporting an astronomical 16:1 compression ratio finish off the short block. 4Piston Racing is a big name in the Honda world, and they hold multiple records in the drag racing community, so it made sense for them to set up the head.

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

IT’S ALL IN THE DETAILS

Ethan’s application is all about getting everything out of 2400cc without the use of a power adder. That means revving high and staying high in the RPM range for extended periods is a must; better flow makes breathing easier. 4Piston machined the head to maximize flow and matched some healthy Web cams to complete the package. A Kinsler intake manifold with its mechanical fuel system supply air and fuel. EFI controls the system with a custom-made harness. Much of the exhaust system is made in-house. The header starts with 1 7/8-inch tubing, moves to 2.0 inches, and then into a 4-1 collector before exiting through a Schoenfield anti-reversion chamber muffler. Ethan’s dad, known as Bundy, assembled and dressed it all with titanium bolts. The motor produces 380hp at a staggering 9,800rpm and 260lb-ft of torque at 7,800rpm, which is very rev-happy.

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

WAIT… WHAT?

Another intriguing aspect of a Midget car is that it doesn’t use a transmission; the DMI splined driveshaft runs from the motor’s rear right into the DMI quick-change and single live axle. Ethan controls getting it in and out of gear; that’s it. This lack of driveline components means it must be push-started to get going. What can you expect from a car that weighs less than 1,000-pounds? After all, it is just a big go-kart.

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

THE COCKPIT AND BODY

There’s nothing but the bare essentials in the cockpit. Ethan keeps an eye on the Tel Tac for RPM and controls on-the-fly suspension tuning, and that’s about it. He turns via a 16-inch Sweet Manufacturing steering wheel, has a titanium brake and gas pedal assembly and sits in a bare-bones The Joie of Seating containment seat with Sabelt’s circle quick-release latch. Every body panel on the Midget is carbon fiber, and Ethan designed the molds from the dash forward, incorporating Chad Boat molds from there back, and Kenny’s Components manufactured it all (and the Speed Demon Bonneville racer we featured on the site).

This 380hp All Motor K24-Swapped USAC Midget Is Changing The Game

LOOKING BACK (AND FORWARD)

When asked what they’d change about the build, they explained a Toyota platform would’ve been more manageable for the team to develop. Although they love the Honda, using a Honda motor has proven challenging, and their learning curve wouldn’t have been as lengthy. It takes a lot more than people realize to build a Midget car. Getting the details working together adds up, and for them, that was the hardest part. For 2021, Ethan is looking forward to racing in the USAC Midget series this season, so keep an eye out for him if you’re following the series. From what I hear, at times, they will have multiple races on the weekend. If it weren’t for his dad and the guys at the shop, Ethan wouldn’t be where he is today; for that, he’s grateful.

Related Links
Ethan Mitchell Instagram
Wes Taylor Instagram
Front Street Media Instagram


Ethan Mitchells USAC Midget

Exterior:Kenny's Components carbon fiber exterior components; custom-built molds from dashboard forward by Ethan Mitchell; Chad Boat molds from dashboard back; graphics by Mwdsgx (Matty Watkins); Spike Chassis nerf bars
Interior:Spike titanium pedals (with carbon heel risers); custom carbon fiber dashboard, Tel Tac tachometer; temp strips for radiator temperature; 16-inch Sweet Manufacturing steering wheel; The Joie of Seating containment seat; Sabelt circle quick release latch
Engine:154 cubic-inch Honda K24 balanced and blueprinted; 4Piston Racing cylinder head work; 99mm stock crankshaft; Carillo rods; JE 16:1 pistons; King engine bearings; 90mm bore, 99mm stroke; Web camshafts; Ferrea rockers; Meziere water pump; Spike Chassis radiator; Kinsler intake manifold with mechanical fuel injection; Walker Performance air filter; EFI ignition; Scott spark plug wires; custom-built header/exhaust with Schoenfield muffler
Chassis:Spike Chassis Chromoly 72-inch; titanium hardware; Brown&Miller Racing Solutions fuel, oil, brake lines; DMI 31-spline Midget quick-change rearend; single live rear axle; Ti Jacobs Ladder bar; front Panhard bar; Factory Kahne twin-tube front shocks, and gas rear shocks; Draco Racing springs; DMI spindles; KSE power steering half box; 19-gal plastic shell with fuel bladder
Wheel/Tire:Keizer 31-spline Midget wheels (13x8-inch front, 13x10-inch left rear, 13x12-inch right rear), Hoosier Midget dirt spec tire (68x7x13 front, 78x10x13 left rear, 82x12x13 right rear)
Brakes:Ultra Lite 10.25-inch front and rear brakes; Wilwood master cylinder

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