Trans4motor R1.1.0 - App Store

The definitive successor to the original Trans4motor is finally here - a new installment that lets you freely explore and animate four-stroke engines on your iPad or iPhone.
Created for those who love internal-combustion engines and never tire of their rhythm, mechanics, and beauty.

【Seamless Engine Morphing】
Switch from inline to V configurations, alter bank angles, change cylinder counts, and adjust firing intervals.
Every change transforms the engine while it continues running.
Camshafts split and merge, crank phasing shifts, valve angles move dynamically - a completely new way to experience engines.

【All-New Transmission Simulation】
For the first time in the series, the gearbox itself is fully visualized.

・3-shaft synchromesh transmission
・2-shaft synchromesh transmission
・Dog gearbox (motorcycle-style)

Enter tooth counts manually, or let the app generate realistic gear meshes from gear ratios.
Follow shift forks, constant-mesh gears, clutch engagement, and truly see how power flows.

【Deep Engine Specification Editing】
Greatly expanded from the original, allowing a far richer expression of each engine’s character.

・Cylinder count, bore, stroke
・Bank angle, mounting angle
・Firing order, firing interval
・Cam drive (belt / chain / gear)
・Valve train (SOHC / DOHC / OHV / VTEC / Desmodromic)
・Valve diameter and included angle (reflected in the CG model)
・Tire width, aspect ratio, wheel diameter (outer diameter calculated automatically)

Recreate everything from spirited singles to distinctive 5-cylinder pulses, modern V4 superbikes, and the bold heartbeat of American V8s.

【Realistic Vehicle Physics】
Not just an animation.
Torque curves, vehicle mass, gear ratios, and tire diameter are calculated frame by frame to determine vehicle speed.
Shift through the gears and feel how the engine and drivetrain connect as acceleration builds.

【Connect with the “Engines” Sharing Platform】
Share your creations with the world.

・Upload / download
・Share to X (formerly Twitter)
・Community “likes” and voting
・Planned competitions

Build a community-driven engine library with fellow enthusiasts.

【GearVision Mode】
Gears, shift forks, clutches - see exactly which components are transmitting power at any moment.
A visualized power-flow mode revealing the inner workings of each shift.

【TechTour】
A hands-on learning mode evolved from the series’ interactive tutorials.

・Four-stroke fundamentals
・Firing order
・Synchromesh mechanisms

Engines become even more fascinating when you understand how they work.

【Enhanced Engine Sound】
With support from Sound Design Lab LLC, this latest audio method combines single-shot, harmonic, and random-noise components to create a natural and realistic engine presence.
Differences in cylinder count and firing intervals come through with greater character and detail.
Engine sound is included as a standard feature, not an in-app purchase.

【Preset Engines】
Trans4motor R includes 12 preset engines ranging from classic icons to modern super-sport engines and powerful V8s.

※ For learning and presentation purposes, the engine CG animations run at one-tenth of real-world rotational speed.
※ This app reproduces engines based on publicly available specifications for educational use and is not intended to be an exact replica of actual machinery, dimensions, or designs.
※ Company names and product names mentioned in this app are trademarks or registered trademarks of their respective owners.

Version History Introducing the new “MotionStep” feature, plus a new “VTEC” chapter in TechTour.
We’ve also redesigned the “Engines” sharing site and refined many details throughout Trans4motor R.

■ MotionStep
Tap at any moment to freeze the engine, then step the crank angle forward or backward to take a closer look at the internal mechanics.
While paused, you can still rotate, pan, and zoom the view freely.

■ TechTour
A new “VTEC” chapter has been added, showing how the VTEC mechanism works.

■ Engines
The “Engines” sharing site has been redesigned.
Official engines and user-created engines are now clearly distinguished, and it’s easier to discover official and newly uploaded engines.
New upload rules also let you share more of your engine creations.

■ Editing
Slider controls in the engine editor have been further improved.
While dragging on the slider, values now snap to larger grid increments for quick, coarse adjustment.
Move your finger up or down away from the slider to switch to progressively finer grid increments, making it easy to fine-tune the value you want.

■ Graphs
A crank-angle indicator has been added to the ignition timing and piston position graph, making it easier to follow how they relate to the current crank angle.

■ Other Improvements
• Refined the motion of internal components such as cams and rocker arms
• Improved automatic clutch engagement when launching from a standstill
• Added selectable Normal/Reverse crank rotation for motorcycle engines
• Made the valve angle adjustable across all engine configurations 1.1.0 20h ago SOHC 2-valve engines now support multi-cylinder (3+) simulation.
Added Port Layout setting: Reverse-flow / Cross-flow (e.g., DATSUN L28).
Added Double-row Timing Chain.

We’ve also published new SOHC examples on the Engine Sharing site:
• NISSAN / DATSUN: Fairlady Z(280Z/S30) / L28 (Reverse-flow)
• BMW: 2002 ti / M10 (Cross-flow)
Download them and start using them right away. 1.0.5 Feb 9 Supports SOHC4 (single-cam, 4 valves per cylinder) engines (e.g., HONDA BEAT).
Added new settings: Curb Weight / Gear Count / Exhaust Side / Crank Direction.
Expanded the minimum valve diameter from 25 mm down to 12 mm.
Added Grip to Throttle Mode (Pedal / Grip) — motorcycle-style throttle (tilt toward you to open).

We’ve also published an SOHC4 example on the Engine Sharing site:
• HONDA: BEAT
Download it and start using it right away. 1.0.4 Jan 12 Support for longitudinal 2-cylinder motorcycle engines (Moto Guzzi / BMW Boxer, etc.)
Added an engine orientation setting (FR/FF, etc.)
Improved fine adjustment with sliders

Sample longitudinal 2-cylinder bike engines are now available on the engine-sharing site:
• OHV: Moto Guzzi / 850 Le Mans
• DOHC: BMW / R nineT
Download and use them right away.

Slider controls: while dragging, move your finger up/down to enter fine-tune mode—the farther you move away, the finer the adjustments. 1.0.3 12/31/2025 Urgent crash fix. We have resolved a crash issue caused by the automatic gear-tooth calculation feature (converting gear ratios into tooth counts). Under certain conditions where the calculation was not possible, the app still allowed the data to be saved, which could lead to crashes.
We sincerely apologize for the inconvenience. 1.0.2 12/19/2025 ・Added a “Max. RPM” setting (up to 18,000 rpm!)
・Fixed an issue where some settings were not saved 1.0.1 12/16/2025 1.0.0 12/11/2025