JUN Auto Mechanic: Japan's Premier Engine Builder for Drag Racing

When a Japanese tuner needs to build a 1,500 horsepower RB26DETT or 2JZ-GTE, they go to JUN Auto Mechanic (ジュン オートメカニック). Founded in 1972 by Junichi Tanaka, JUN Auto Mechanic is Japan's premier precision engine building specialist — the shop that other shops trust when they need engines that won't fail at extreme power levels. JUN built cars that dominated Japanese drag racing through the 1990s and 2000s, including multiple 1,000+ horsepower street-legal Supras, Skylines, and 300ZXs.

The Founder: Junichi Tanaka

Junichi Tanaka was an experienced Japanese touring car mechanic in the 1960s, working for various race teams. Tanaka Industrial Co. Ltd founded the JUN research division in 1946, which later became JUN Auto Mechanic with a singular focus: building precision engines for competition use. Unlike tuners who chase horsepower first and reliability second, Tanaka built his reputation on engines that could make extreme power AND survive long enough to be useful.

Tanaka's machining philosophy prioritizes:

1. Component balancing to competition specifications (0.1 gram tolerance on rotating assembly)
2. Oil clearance calculations per material and temperature (not generic rules of thumb)
3. Deck height blueprinting (actual measurements on every rebuild, not assumption of factory specs)
4. Bore measurements before and after honing (verifying cylinder walls are perfectly round)

This attention to detail comes at a price — a JUN Auto Mechanic RB26DETT rebuild costs 2-3x the price of a generic Japanese shop rebuild — but the engines are bulletproof.

Famous Builds

JUN Super Lemon R34 GT-R (1,001 HP AWD Drag Car)

The most famous JUN build is the "JUN Super Lemon" R34 GT-R, a bright yellow drag car with a fully-built RB26DETT producing approximately 1,001 horsepower at the crank. The car was one of the first AWD drag cars to consistently run in the low 8-second quarter mile range at over 170 mph — a remarkable achievement for a fully-sealed AWD drivetrain.

The Super Lemon appeared in numerous Japanese magazines in the early 2000s and became an icon of the R34 GT-R tuner scene. The car is still in Japan today and occasionally makes appearances at drag events.

JUN Supra MK4 A80 Drag Car

A custom Supra MK4 with a JUN-built 2JZ-GTE producing approximately 1,200 horsepower. Ran 7-second quarter miles at over 180 mph in drag competition. Built in the mid-2000s during Japan's peak drag racing era.

JUN 300ZX Z32 Twin Turbo Drag Car

A less-known but equally extreme build: a Nissan 300ZX Z32 with a heavily-built VG30DETT producing 800+ HP. Demonstrated that the VG30 could compete with the more famous JZ and RB engines.

Engineering Specialty: Precision Machining

JUN Auto Mechanic's reputation is built on machining tolerances that exceed factory specifications. Their engines undergo:

Deck Surface Truing

Every engine block has its deck surface machined perfectly flat before assembly. Factory blocks are usually within 0.002" of flat, but JUN machines them to 0.0005" — reducing the risk of head gasket failure at extreme cylinder pressures.

Rotating Assembly Balancing

Crankshafts, connecting rods, pistons, and flywheels are all individually weighed and balanced. Target tolerance: 0.1 gram variance across the rotating assembly. This reduces vibration at high RPM and allows engines to safely rev to 9,000+ rpm without destructive harmonics.

Cylinder Wall Blueprinting

After honing, each cylinder is measured at multiple points to verify perfect roundness and proper taper. Cylinders outside tolerance are re-honed or bored oversize.

Main Bearing Alignment

The main bearing bores in the block are align-bored to verify perfect crankshaft centerline alignment. Factory blocks are usually "good enough" but JUN machines them to race specifications.

Signature Products

JUN Forged Pistons

Custom forged pistons for RB26DETT, 2JZ-GTE, 4G63T, and SR20DET. Made with proprietary aluminum alloy and specific coating for reduced friction and thermal stability.

JUN Connecting Rods

H-beam and I-beam forged steel connecting rods rated for extreme boost applications. Used by competitors outside of JUN's own builds.

JUN Stroker Kits

Increased-displacement rotating assemblies for RB26DETT (2.8L, 3.0L) and 2JZ-GTE (3.4L, 3.5L). Include forged crankshaft, rods, pistons, and bearings.

JUN Oil Pumps and Cooling Systems

High-volume oil pumps and upgraded cooling components for high-HP builds. The RB26 JUN oil pump is particularly famous for solving the factory pump's high-RPM oil pressure issues.

Drag Racing Heritage

JUN Auto Mechanic was a dominant force in Japanese drag racing from approximately 1995 to 2010. Their cars — mostly Supras, GT-Rs, and the occasional Silvia or 300ZX — competed at major drag events across Japan, routinely running 7-8 second quarter miles.

Japanese drag racing in that era was divided between two major events: the Hot Version Circuit Attack events (shop time attacks at Tsukuba) and the Drag Nationals at various dragstrips. JUN specialized in drag nationals, where straight-line speed and launch consistency mattered most.

The rise of Formula Drift and the decline of Japanese drag racing (due to track closures and costs) reduced JUN's public profile in the 2010s. But the shop continues to build precision engines for customers worldwide.

Why JUN Matters

JUN Auto Mechanic represents a specific engineering discipline: precision over speed. Junichi Tanaka built his reputation on engines that don't fail, even at extreme power levels, because they're built with measurement-obsessed discipline that most shops lack. When a tuner needs a 1,500 HP engine that will actually hold together for more than a few drag passes, JUN is the destination.

Today, JUN still operates from its workshop in Japan. The shop has expanded to include customer projects from around the world — wealthy collectors ship their Supras and GT-Rs to JUN for full rebuilds, then ship them back after months of machining work. For serious Japanese performance enthusiasts, a JUN-built engine is the hallmark of a no-compromise build.