Behind the Build

Jack Shanahan's BMW E82 1 Series

16 days. That’s how long Jack Shanahan had to build a competition-ready drift car from what turned out to be a bare shell. No engine. No wiring. No drivetrain. Just a cage, a deadline, and the kind of stubbornness that makes elite-level motorsport actually happen.

Welcome to Behind the Build.

The Build That Almost Wasn’t

The Build That Almost Wasn't

Jack Shanahan didn't plan on running Formula Drift in his own car this season. The decision came in late January, early February, a last-minute commitment that sent him scrambling for a chassis. He found one through Sam Megumi: a BMW E82 1 Series shell with a roll cage already inside. The catch? When Jack flew to
California and saw it in person, it was exactly that. A shell. Nothing else.

What followed was a 16-day sprint to build a full competition car. Jack did the fabrication and assembly himself. His crew chief flew in from home and matched him wrench for wrench. Lloyd, his tuner, pre-built the entire wiring loom back in Ireland using rough measurements off a 1 Series sitting in Jack's dad's scrapyard. When everything landed in California, it all came together somehow, precisely. As Jack put it, the wiring is a genuine 10 out of 10.

That's not a typical build story. That's a war story.

The Engine: A BMW S54 Running Where It Has No Business Running

Pop the hood, and you find the heart of the whole experiment. An S54 pulled from a BMW E46 M3, standing upright in a chassis it was never designed for. The S54 is one of the greatest naturally aspirated inline-sixes BMW ever built. In turbo form inside a 1 Series, it's a very different conversation.

Because the engine is rotated upright in the E82 bay, it needed a custom sump to accommodate the oil galleries sitting on the wrong side. It runs dual pickup on the sump and still runs wet, not dry, even though the rotated position makes it look otherwise. The block is sleeved and fully forged, with 5150 internals. The head runs stock ports and cams with upgraded valve springs. Nothing exotic, nothing unnecessary.

The turbo setup went a different direction from the car Jack drove last year. Instead of a long manifold with a V-band setup, this car runs a T4 twin-scroll configuration with a Pulsar 7170 turbo and custom manifolds from a fabricator in Europe. The result is more of a grunt-forward sound, less high-pitched and rev-focused, more the M-car tone Jack wanted. On the dyno, the car sings.

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Power figures tell an interesting story:

Without nitrous: approximately 800whp
With nitrous: 850whp and just under 700 lb-ft of torque

The nitrous isn't there for peak power. It's there to spool the turbo faster and address the S54's only real weakness in this application: mid-range torque. VANOS was deleted, and because the engine is sleeved down to roughly 85.5mm pistons, cam timing movement is limited to around 20-25 degrees before the valves hit the pistons. That restriction reduces the torque the engine would otherwise produce. The nitrous fills that gap. Without it, Jack's own 2JZ back home makes more torque. With it, the S54 comes close.

The real-world driving challenge? The S54 only gives you about 2,000-2,500 RPM of usable power band. You're almost flat-throttle the entire run just to keep it in the zone. The ECU logs make it obvious. Jack's throttle trace in this car looks nothing like anything else he drives.

Engine Components:

S54 from BMW E46 M3, sleeved block, fully forged bottom end (5150)
Pulsar 7170 Turbocharger
Custom T4 twin-scroll manifold
Stock head, stock cams, upgraded valve springs
Custom wet sump (dual pickup)
Radium Engineering BMW E46 M3 S54 Fuel Rail Kit
Radium Engineering Fuel Pressure Regulator Damper (Black)
Radium Engineering Competition Catch Can XL VTA/VTE
Radium Engineering Coolant Expansion Tank (Universal)
Davies Craig Electric Water Pump
CSF Motorsport Radiator with Shroud, 14" SPAL Brushless Fans and Harnesses
Nitrous Express Universal Nitrous Kit for EFI with 10lb Bottle

Fuel System: Radium All the Way Through

The fuel system is clean and purpose-built, anchored by a Radium cell in the rear of the car with a full surge tank setup to keep delivery consistent under sustained sideways load.

Suspension and Steering: WiseFab Front and Rear
The suspension philosophy is straightforward: everything it needs, in the simplest possible form. That was the brief Jack set from day one, and the build reflects it.

Both front and rear run WiseFab. The front drift angle lock kit gives Jack the steering geometry and angle he needs to push the E82 as aggressively as the multi-link rear will allow. It still runs the mechanical E90 rack with electric power steering assist, not a full electric rack, but fluid-assisted through the factory setup. Custom geometry adjustments were made to increase front camber and tighten the front-end response.

Out back, the WiseFab rear drop knuckle kit handles grip adjustment and geometry correction for the E82's rear suspension. The car is currently running without a front sway bar because the dual-pickup front sump sits too low to clear the WiseFab bar without a full day of fabrication. Jack recently fitted an FDF DIY rear sway bar with a chromoly bar to address a checking issue the car was developing. Anti-squat geometry in the rear was also changed because the previous setting caused the shock to bind under power and behave like a solid bar, killing compliance right when it was needed most.

It's still being dialed in. Jack is the first to admit the E82 is a funky chassis. The multi-link rear suspension doesn't give you the same clean setup relationship as the GT86 he came from. But he's figuring it out round by round.

THE TRACK RECORD MATTERS WHEN BUILDING

Drivetrain: Samsonas RS90 Sequential

The transmission choice was personal. Jack has been running Samsonas since 2015. He tried an H-pattern G-Force setup in last year's car and found himself missing the shifter mid-run. It sat outside his field of view, and the muscle memory just wasn't there. He came back to what he knows.

The RS90 is Samsonas' higher-horsepower-rated sequential box, and Jack's confidence in it comes from real data. The same gearbox has been running in a car at home in Ireland for three full seasons. Opened twice. Nothing replaced. That track record matters when you're building a car in 16 days and need to trust your components.

Samsonas RS90 Sequential Gearbox
Speed Tek Quick Change rear end

Electronics and Engine Management: Full ECU Master Stack

The electronics package is a full ECU Master ecosystem managed by Lloyd, Jack's tuner, who pre-wired the entire loom in Ireland before the car existed in California. Two PDMs run the car, split front and rear. The front unit handles everything in the engine bay. The rear handles fuel pumps, taillights, nitrous, and the back half of the car. Clean, logical, and fault-tolerant.

Interior: OEM-ish, On Purpose

The cage came with the shell. A basic setup with NASCAR-style door bars, enough to pass tech and keep the driver safe. Inside, Jack runs Sabelt harnesses and a Sabelt GT pad on the driver's side. The Samsonas shifter sits where he can reach it. The WiseFab hydraulic handbrake is positioned upright because his coach Connor told him he drives better that way, so he's trusting that call for the season.

The dash is a 2F Performance S15 Nissan Silvia-style fiberglass unit, a creative solution to a rulebook problem. Formula Drift requires an OEM-style dash, and Jack's argument is that an S15 dash is technically factory for something. The Wilwood pedal assembly handles brake and clutch inputs for a reverse-swing-mount setup. On the roof, there's a steel plate welded in for a GoPro magnet mount, because the single magnet wasn't strong enough and the camera flew off during a run. Engineering happens in real time.

The Philosophy Behind All of It

Jack was direct about what changed between last year and this one. When he drove Rome's car in 2024, it was someone else's machine with someone else's setup philosophy. He couldn't push the changes he wanted. Results were a mixed bag. Podium at Long Beach, top 16 exit at Atlanta. The gap between what he felt the car needed and what he could actually do to it gnawed at him all season.

This year, when anything goes wrong, it's on him. That accountability is exactly what he wanted. Every decision, from the S54 swap to the Samsonas to the rear sway bar bolted on the week of the event, came from Jack's own read of what the car needed. He does his own fabrication, assembly, and setup work. The crew supports him, but the direction is his.

The E82 is still being figured out. The engine is being refined. The suspension is being sorted corner by corner. But the car is his, and that changes everything.

That's what Behind the Build is about.