A Korean M850 fan used AI to build an engine simulator, relying on his own throttle-blip videos to hit 66k Android installs in just over a month
What it is A phone engine simulator: 12 3D engines with the internals visible. Push the throttle and shift gears and you hear the sound synthesized in real time. Watch one ad to unlock an engine for 24 hours.
Why it took off The developer is a car nut. Every day or two he posts a loud throttle-blip video on TikTok, with the sound cranked up and the pistons spinning, and each one gets 15 to 550k views. When commenters ask for a specific engine, his next video delivers it. Localizing into 17 languages spread it across dozens of countries.
BHow you could follow it Skip engines. Take this playbook to something else that sounds and looks good out of the box (motorcycles, gunshots, mechanical watches, trains). Post screen-recorded short videos yourself every day, put the app name on screen, and fill the gaps it leaves: progression and tuning.
- Data (updated daily) · First launched 2026-09-28 · Korean rating 99 · 11-08 charted in 25 stores
iOS · Overall Top Free rank · by store Data 2026-10-30 → 2026-10-31 (2 days, 2 observations). Lower rank is higher; gaps mean it wasn't charted that dayiOS · Number of stores charted (top 200 on any chart) Data 2026-10-30 → 2026-10-31 (2 days, 2 observations)iOS · rating count · Korea Data 2026-10-28 → 2026-11-08 (12 days, 12 observations). Apple doesn't publish download counts; rating growth is a proxy for downloads.
Engine Simulator 3D (called 엔진 시뮬레이터 in the Korean store) is a sound simulator that lets you see inside the engine: 12 see-through 3D engines. Drag the throttle, shift gears, and the pistons and crankshaft turn with the sound, which is synthesized in real time. Launched on 28 Sep. A little over a month later it had 66k installs on Google Play, and 36 storefronts on iOS add up to 600 ratings. Users mainly come from the developer's own TikTok. He was already posting videos of his car's exhaust under a car-fan account. Once he switched to throttle footage from the app, single-video views went from a thousand or two to 550k. But this category already has a leader several times bigger that went up this year, and many others are working on it at the same time.
From exhaust videos to a simulator
The TikTok account @baechoo24, run by 배기열, started as an ordinary car-fan account. In 2024 he posted tunnel acceleration of a BMW M2. In 2025 he switched to an M850i, posting cold starts, backfires, and launch control. Most videos got a thousand or two views. His best was a 0-100 run in the M850i, at 59k.
In 2026 Sep 17 he posted a launch-control exhaust video for the M850i, which got 2,046 views. 6 days later, on 23 Sep, the content changed: "엔진 시뮬레이터 앱 만들었습니다" (I made an engine simulator app), 15k views. On 27 Sep he asked viewers in the video what features they wanted. On 28 Sep the app went up on the App Store. That day's video was titled "The engine simulator that went viral for the first time (?), finally launched worldwide (iOS first)".
For the next month he posted roughly every day or two, always with the same frame: sound turned all the way up, a see-through engine in the middle of the screen, a finger pushing the throttle and shifting gears, and the tachometer hitting the redline.
| Date | Video | TikTok views |
|---|---|---|
| 10-01 | "N gear feels more natural now" | 350k |
| 10-13 | "The first big update is coming" | 420k |
| 10-15 | "Reached 300 km/h" (V10) | 217k |
| 10-23 | "Next update: naturally aspirated V8" | 557k |
| 10-23 | "V8 + N/A + MT" | 370k |
| 11-02 | "Big patch done" (all 12 engine models redone) | 148k |
(checked on TikTok @baechoo24,11-06; account has about 3,900 followers)
He's the developer and also the host of his own product. The founder said on Threads that he had been a product engineer for 10 years, and at the end of 2025 he went out on his own to found the one-person company Groundcode. He wrote the app with AI (his words: 바이브코딩, vibe coding).
What it is
Open it and you get an inline-six engine, for free. 11 more engines are available, from three-cylinder, V8, and V12 up to rotary engines. Pick one and watch a rewarded video to unlock that engine for 24 hours. You can drag to spin the engine, switch to a cutaway to see how pistons, rods, crank, and rotors move, slow down combustion, and watch the exhaust flame. On the driving side there are manual, automatic, dual-clutch, and launch control. A banner sits at the bottom. There are no in-app purchases and no login.
It uses web technology (Three.js for 3D, Web Audio for sound), so the same code shipped in several versions. The first release actually went to Toss, the Korean payments app, as a mini-program that needs no install. Then came iOS (9-28) and Google Play (10-06). The UI is available in 17 languages, and the store names are localized too: エンジンシミュレーター 3D in Japan, Motorsimulator 3D in Germany, Simulatore di Motore 3D in Italy. In five weeks it went from 1.2 to 1.4.2.
How much it grew
| Metric | Sources | |
|---|---|---|
| Google Play | 66,228 installs, over 14,894 in the last week; 504 ratings | Google Play,11-06 |
| iOS ratings | 36 storefronts total about 631; US 111 (4.78 stars), Korea 97 (4.63 stars) | App Store,11-06 |
| iOS growth rate | The charted storefronts added 78 ratings in a week, 11-03 alone got 22 in one day, right after the big update | App Store, 10-28 to 11-06 |
| Charts | Only charted on the Entertainment category's Top Free chart, peaking at #5 in Montserrat; #48 on the South Korea store 11-06; charted countries grew from 20 to 67 (10-31 11-05); never reached the overall chart in any country | App Store |
| Day 2 after launch | iOS downloads passed 4,600 | Founder on Threads, 10-01 |
Android volume is much bigger than iOS. Some real Korean users are inside the Toss mini-program, which outside observers can't see. Charting in dozens of small countries' entertainment charts is not hard: storefronts like Suriname or Montserrat need only a few downloads a day to reach the top 50, and localized store names help.
Where users come from
It's mostly his own TikTok. Recently 10 engine-related videos together got about 1.3M views. Loud throttle sound plus visible pistons needs no explanation, so it reaches people who don't speak Korean. The comments come in Russian, Spanish, Turkish, Indonesian, and more.
One thing stands out in the comments: the most-liked questions are almost all "what's this game called?" On the 10-23 video with 370k views, more than a dozen of the top 30 comments ask for the name: "game name plssss", "cómo se llama el juego", "как игра называется", "어떤겜임". The app name isn't printed in the video, which just says "see the link in profile". It's fair to infer that every hit video loses many people who want to download it.
The other half of the comments are wish lists: "add 7 speed manual", "can I import my own recorded engine sound", "no motorcycles?", "bigger turbo, add a blow-off valve", "any 1.3 Multijet?" He treats these as topics for the next video. Someone asked for a boxer engine, so on Oct 26 he posted "the boxer engine is ready to scream"; someone wanted a modern Elantra N, so on Oct 31 he teased "Elantra N coming soon". Wish, update, post, repeat.
The other channels are tiny: a GeekNews post (Korean developer community) titled "Engine simulator made by a car fan with vibe coding" (10-06) got only 3 points and 2 comments; a Threads post showing "Day 2, 4,600 downloads" got 2,300 views. I found no evidence of paid ads.
Where the money comes from
Ads only: a rewarded video unlocks an engine for 24 hours, plus one banner. Revenue isn't public. Many of its users are in small countries with very low eCPMs, and some come through the Toss side, so monthly ad revenue is probably modest. Commenters complain too: "make the engines free", "remove the ads", "you say to watch an ad to unlock, but I opened it with data and can't watch it".
Who it's competing with
This isn't a category it invented. In 2022 AngeTheGreat put a desktop engine simulator on YouTube, and that's how people learned about real-time synthesized engine sound. In 2026 several groups brought the idea to phones at the same time.
| Product | Scale | How it differs |
|---|---|---|
| Engine Sim - Sound Simulator (Takasawa Dynamics, Japan; on iOS since 7-15) | 1,204 ratings in the US store (4.57 stars), over 5,500 combined across storefronts; 327k installs on Google Play, 53k in a week; top few in the racing games category in Saudi Arabia and the UAE | The category leader. 28 engines, sound only with no cutaway view, but a full game loop: drive to earn mileage, upgrade parts, open boxes, daily missions, leaderboards |
| Engine Simulator (MUHAMMAD SAAD ATA, launched in May) | 183 ratings in the US store, spread across 90+ countries | Same name, small volume, no 3D cutaway |
| Simulation Moteur (grimvexgames, France) | The developer's own TikTok: 1.03M views on a single video | Same playbook of building reach through the developer's own videos, focused on tearing down and modifying engines |
| enginesimulator.app | Unknown | Hardcore niche: building engines, ECU tuning, dyno testing |
| realenginesimulator.com and other web versions | Unknown | Runs in the browser with no install, 46 engines |
| RevHeadz Engine Sounds(2014) | 1,386 ratings in the US store, growth has basically stalled | Old-school approach: plays back pre-recorded sounds |
Engine Sim came out two and a half months earlier. Its Android installs are 5 times this app's, and it adds more than 3 times as many weekly. It wins on being visual: the 3D cutaway is exactly the footage that works on TikTok, so its differentiation and its acquisition are really the same thing. But this hasn't pulled the leader's users away yet. Another Korean account's "Engine Maker" video got 3.7M views, and an Android app called Car Engine Simulator already has a nearly identical description 3D.
The founder is copying this playbook himself. On Oct 16 he posted "Inspired by the Tesla Roadster, I made a skateboard kickflip simulator (Kickflip Simulator)" (160k views). In November he released Weapon Simulator 3D. He said it was his first Reddit post: half a day, 300 upvotes, 85k views, and it reached the top 100 on the App Store.
If it were you
B. You can copy the playbook, but don't build another engine simulator. The category already has a leader several times bigger that went up this year and has a game loop. Five or six people are building on phone and web at once, pure ad monetization gives little, and users are mostly in small countries. Piling in now won't win much. What's worth taking is the playbook: pick something that sounds and looks good out of the box, turn it into a simulator, and have the developer post videos every day. Few people outside know this playbook yet, and a solo developer with AI can build it in a few weeks.
Who it suits: people already inside a hardcore hobby (cars, motorcycles, firearms, mechanical watches, instruments, trains), indie developers who can shoot good-looking phone footage and keep posting a short video every other day, and front-end developers who can write Three.js and Web Audio.
Who it doesn't suit: people who don't want to be on camera or make content themselves (nearly all of its traffic comes from the founder's account); people hoping to earn from subscriptions (these users come to play around, have low willingness to pay, and at most spend small amounts on single upgrades); people planning to go head-to-head with Engine Sim.
How to do it:
- Build something else: comments have already asked for motorcycles. Others include gunshots, mechanical watch movements, aircraft engines, steam trains, power drills and chainsaws. The bar is picture and sound working together, understandable within three seconds without explanation.
- Fixing the two things it gets wrong: first, retention. Take a page from Engine Sim: add mileage, mods, and parts upgrades, or users will play for a day and leave. Second, customization. Users are asking for "import your own sound" and "put on a big turbo, add a blow-off valve", and that's exactly where an in-app purchase can go.
- One web codebase ships to web, iOS, and Android. Localize the store names and start with 〔15〕 or more languages.
How to get users: Run your own TikTok, Reels, and Shorts accounts and post one video every 1 to 2 days. The footage is real in-app screen recording, sound all the way up. Put the app name on screen in the video, so the comments aren't full of "what's this game called?" Each video answers a wish from the comments, and the next video ships that feature. Then post once in the matching Reddit hobby subs. That's how Groundcode's weapon simulator broke into the top 100.
When to get in: The window for engine sims is essentially closed. For other categories' "sound-first" simulators, the window is open now, while 2026 years of this hasn't saturated them. Ship within a few months. Once every category has a leader with a real game loop, you're late.
Signs you've misread it: If you post for a month and no single video gets past 100k views, your pick doesn't have enough built-in hook for outside viewers. Change the category, don't add features. And if Groundcode's own skateboard and weapon simulators never take off, then the engine sim wave was riding demand AngeTheGreat left behind. The playbook alone can't be copied.
Research notes: competitor table, acquisition evidence, full research report
- Competitors
Name Where Launched Scale How it differs from this one Engine Sim - Sound Simulator(Takasawa Dynamics) iOS 2026-07-15(Play 2026-09-12) iOS US 1,204 rating. Charted in 86 stores, 5,551,7 days total, +499. Gulf-state racing charts top 3–8. Play: 327k installs, +7k in 53 days. The category leader, 28 engines. It does sound only, with no 3D cutaway, but it has a complete game loop: drive to earn mileage, upgrade parts, open crates, daily tasks. Groundcode wins on visuals. Its scale is about 1/5 of this one. Engine Simulator(MUHAMMAD SAAD ATA) iOS 2026-05-27 Charted in 97 stores, 432 ratings combined, +7 in 98 days. US: 183. Same-name competitor. Wider country spread but low volume, and no 3D cutaway. RevHeadz Engine Sounds iOS 2014-02 US 1,386 ratings. Growth has mostly stalled. Plays recorded audio on a loop. Not real-time synthesis. AngeTheGreat Engine Simulator Open source 2022 YouTube series with single episodes in the hundreds of thousands of views. Has a r/enginesimulator community. Hardcore physics sim on PC. It's the demand source for the whole category. No mobile version. Engine Simulator(enginesimulator.app) iOS 2026 (unverified) Unknown Hardcore direction: engine builder, ECU tuning, dyno. Groundcode is a light toy. Simulation Moteur(grimvexgames) iOS Around 2026-09 Single TikTok videos with 1.03M views French developer, also grows by posting TikToks himself. Focus is blowing up and modding engines. realenginesimulator.com and other web versions Web 2026 Unknown Runs in the browser with no install, 46 engines - Where users come from
- Verified founder's own TikTok (@baechoo24): 3,860 followers, 61k likes; since 9-23 posting every 2–3 days, single videos at 556k / 420k / 370k / 350k / 217k / 147k views, the last 10 videos totaling about 1.3M; 9-28 the video that says "first viral hit, global launch" (TikHub)
- Verified Toss mini-app launched first: the site says "use it in Toss, no install needed." The founder posted "현재 토스로 먼저 배포" (deployed to Toss first), with iOS and Android following.
- Verified Public dev log on Threads / Instagram: @groundcode.io posted "day 2 of ops, iOS downloads 4,600" (2.3K views). Instagram has an intro video, "engine simulator built with Opus 5.5."
- Verified GeekNews Show GN: 2026-10-06 "Engine simulator built with vibe coding by 차쟁이", 3 points, 2 comments, low volume
- Verified Multilingual ASO and small-country charts: UI in 17 languages, store names localized per storefront. Also listed on entertainment free charts in 53–67 small countries (appstore library).
- Inferred Paid acquisition: the data card mentions reviews saying "came from an ad," but I found no ad library or review evidence.
Why Engine Simulator / 엔진 시뮬레이터 3D (Groundcode) worked
Data card: ios_6814764131 · App Store id6814764131 · launched 2026-09-28 · free, ad-only (rewarded video + bottom banner) · research date 2026-11-06
Bottom line
This is a one-person Korean company, Groundcode (founder 배기열, 10 years a product engineer, started the company at the end of 2025), that used AI to write a toy with a 3D cutaway engine and real-time synthesized sound. It didn't invent the category. It's a late entrant in the 2026 wave of "phone engine sound simulators." It got traction mainly because the founder's own TikTok, @baechoo24, posts a "rev the engine" short every two or three days (150k to 560k views per video), plus cold-start push through Toss mini-app, Threads, and GeekNews, the Korean developer circles. The product difference is that you can see the 3D engine inside (pistons, crank, rotor cross-sections), paired with manual and dual-clutch driving. That's exactly the most eye-catching footage for short video, so the differentiation and the growth tactic are the same thing. Volume is still small, about an order of magnitude below the category leader, Engine Sim (Takasawa Dynamics).
1. Data: how big it is now
Which stores I checked: I scanned all 115 storefronts in the library first, then used Apple's lookup API to check 36 major stores more (the US store isn't in our chart library, so the US is missing from the combined total on the data card).
- iOS rating count: Apple lookup (2026-11-06) across 36 stores gives about 631 ratings combined. US 111 (average 4.78), Korea 97, Japan 38, France 38, Italy 29, Thailand 29, Turkey 26, Brazil 24, Russia 22, Germany 21, Canada 20. The data card's 305 counts only the stores where it charts.
- Rating growth: the appstore library's app_profile shows 7 new ratings in the charted stores over 78 days (11-06). That's 1–22 new a day, peaking on 11-03 (22), which lines up with the 11-02 major version and the TikTok videos.
- Charts: only on entertainment (6016) free charts, and only in small countries. Best position was #5 in Montserrat (10-30) and #16 in Suriname (11-05). Korea ranked #11-06 (48). Charted-store count went from 10-31 to 20 to 11-05 to 67 (appstore library app_day). Never charted on any country's overall chart.
- Android: Google Play 66,228 installs, +7 in 14,894 days, rating 504 (googleplay library app_profile, 11-06), listed 2026-09-26. Android volume is bigger than iOS.
- Public numbers from the founder: "Day 2 of operations, iOS downloads passed 4,600" (Threads @groundcode.io, 2026-10-01,2.3K views). www.threads.com/@groundcode.io/post/Dd9DRfLGqKJ
- Iteration speed: from 5 to 1.2.7 within 1.4.2 weeks (appstore library app_day). 11-02 was a major version. All 12 engines' 3D models were redone (TikTok @baechoo24 "big patch complete").
- Monetization: the straight-six engine is free by default. Each rewarded video unlocks the other engines for 24 hours on that device. There's a bottom banner. No in-app purchases (App Store description). Revenue isn't public, and I found no revenue figures.
II. Competitors: a category getting crowded in 2026 years
| Product | Where | Launched | Scale | How Groundcode differs |
|---|---|---|---|---|
| Engine Sim - Sound Simulator (Sena Takasawa / Takasawa Dynamics, Japan) | iOS + Android | iOS 2026-07-15,Play 2026-09-12 | iOS US 1,204 rating. Charted in 86 stores, 5,551,7 days total, +499. Racing games rank #3–8 in Saudi Arabia, UAE, Kuwait, Oman. Category #1 in one store. Best overall free chart #71 (appstore library 10-31). Play: 327k installs, +53k in 7 days. | The category leader. 28 engines, sound only, no 3D cutaway. It has a full game loop: drive to earn mileage, upgrade parts, open crates, daily tasks, leaderboards, invite codes. No ads on the driving screen. Groundcode wins on visuals and loses on retention design and scale. |
| Engine Simulator(MUHAMMAD SAAD ATA) | iOS | 2026-05-27 | Charted in 97 stores, 432 ratings combined, +7 in 98 days. US 183 (average 4.32). | Same-name competitor, wide spread but low volume. TikTok @iosenginesimulator is likely its promo account (video reads "Engine Simulator on app store (blue…)", unverified). |
| RevHeadz Engine Sounds | iOS | 2014 | US 1,386 ratings, about +1 in 7 days. | The older approach: plays recordings, crossfades. Not real-time synthesis. |
| Sports Car Engines(ARE Apps) | iOS | 2009 | Charted in 82 stores, 56 ratings combined. | An early recording-based app that's no longer active. |
| Engine Simulator(enginesimulator.app) | iOS/iPad/Mac | 2026 (date unverified) | Unknown | Hardcore direction: rigid-body physics, engine builder, ECU tuning, dyno. Ports the engine sims popular on PC (r/simracing posts). |
| AngeTheGreat Engine Simulator | PC / open source | 2022 | YouTube series with single episodes in the hundreds of thousands of views. Has a r/enginesimulator community. | The demand source for the whole category. After it went viral on YouTube in 2022, "real-time synthesized engine sound" became a known concept. PC only. |
| Simulation Moteur (@grimvexgames.fr, France) | iOS + Android | Around 2026-09 | TikTok single video 1.03M views (10-15), 290k (10-17) | Also grows through the developer's own TikToks. Focus is blowing up and modding engines. |
| Engine Maker 1.0 (@dominator.tornado.kr, Korea) | PC / document distribution | 2026-10 | TikTok single video 3.7M views (10-02) | Not a store app, but it shows "revving an engine" videos spread naturally on TikTok. |
| realenginesimulator.com and other web versions | Web | 2026 | Unknown | 46 engines, no install, runs in the browser |
| Car Engine Simulator 3D(net.kilho.enginesimulator) | Android | Not verified | Unknown | Descriptions are nearly identical (3D pistons, crank, valves + throttle). Likely a copycat. |
Takeaway: the first to break out in the category was Takasawa's Engine Sim (July). Groundcode came about 2.5 months later, and at least 3–4 other indie developers were building the same thing in the same period.
3. Growth: where users come from
- The founder's own TikTok @baechoo24 (confirmed, main source): 3,860 followers, 61K likes total (TikHub, 11-06). Starting from 9-23 with "I made an engine simulator app," they post every 2–3 days. Every video is "sound turned all the way up + 3D engine + shifting gears and flooring it," with bilingual Chinese and Korean subtitles. Representative videos: "Next update: naturally aspirated V8" 556K views (10-23), "1 차 업데이트 곧 공개" 420K (10-13), "V8 + N/A + MT" 370K (10-23), "N gear feels more natural" 350K (10-01), "Hit 300 km/h" 217K (10-15), "Big patch done" 147K (11-02). The last 10 videos add up to roughly 1.3M views. The 9-28 post says it straight: "First engine simulator to go viral (?) and finally launched worldwide (iOS first)." Commenters ask for specific engines (flat-plane, Elantra N), and the next video ships them, creating a loop of wish → update → video.
- Toss mini-app launched first (confirmed): the site says "Android, iPhone, or use it in Toss with no install." The founder posted "현재 토스로 먼저 배포" (currently deploying to Toss first), then iOS and Android. Toss has 30M users, which may explain why Korea ranks high among the iOS rating counts, though much of Korean real usage happens outside the App Store.
- Public dev log on Threads / Instagram (confirmed): @groundcode.io posted "what features to add in development" and "day 2 downloads 4,600" on Threads. Instagram has an intro video, "engine simulator built with Opus 5.5."
- GeekNews Show GN (confirmed, but tiny volume): 2026-10-06「차쟁이가 바이브코딩으로 만든 엔진 시뮬레이터」, 3 points, 2 comments. news.hada.io/topic?id=34886
- Reddit: The founder says they had never posted on Reddit before; in early November they posted for the first time, and it was for another app, 「무기 시뮬레이터 3D」: 300 upvotes in half a day, 85k views, and it broke into the top 100 on the App Store (Threads). No major Reddit thread turned up for the engine simulator.
- Multi-language ASO (confirmed): App UI in 17 languages, store name localized by store (Korean: 엔진 시뮬레이터, Japanese: エンジンシミュレーター 3D, German: Motorsimulator 3D, Italian: Simulatore di Motore 3D, Russian: Симулятор двигателя 3D). This likely explains why it sat on the entertainment charts of 50–67 small countries at once, since the bar in those markets is low.
- Paid acquisition (no evidence found): The data card says a comment mentioned coming from a video and an ad, but we have no review samples for this app and the ad library doesn't track it. Based on current evidence, "video" more likely refers to its own TikTok. Whether it ran ads is unverified.
IV. Why it made it onto the charts
- The category's demand was already proven: AngeTheGreat made "real-time synthesized engine sound" popular 2022 years ago, and Engine Sim moved it to phones 2026 years ago in July, reaching the top of the racing category in Saudi Arabia and other Gulf countries (appstore library). By the time Groundcode arrived, both the demand and the keywords already existed.
- The content is naturally suited to short video: Revving sound plus an X-ray view of the engine needs no explanation, and playing it out loud is the hook. Similar accounts like @grimvexgames.fr (1.03M) and @dominator.tornado.kr (3.7M) also grew through their own videos, which suggests the growth came from the content format, not from budget.
- AI lets one person iterate fast: The founder has publicly said it was built with Opus 5.5 / "vibe coding"; the frontend is web tech (React + Three.js + Web Audio), and the same codebase ships as a Toss mini-app, a website, iOS, and Android. In 5 weeks they shipped 10+ versions and turned engines users asked for into the topics of their next videos.
- Monetization has almost no barrier: No login, the default engine is free, and switching engines means watching one rewarded video. It doesn't interrupt the experience, which keeps ratings high (US average 4.78).
- Small-country charts are easy to enter: With 17 languages and localized store names, a few downloads a day can put it in the top 50 in tiny storefronts like Suriname or Montserrat, and charting brings a bit of organic exposure.
5. Differentiation
- Compared with Engine Sim (Takasawa): Engine Sim wins on sound realism, engine count (28 engines), and game-style retention. Groundcode wins on being visible: 3D cutaway, slow-motion combustion, exhaust flames, four camera angles, and four backgrounds, plus manual, automatic, dual-clutch, and launch-control modes.
- Is that difference the reason it made it? Partly. Visualization is itself TikTok material, so its videos are easier to shoot and spread than a sound-only app, and differentiation and acquisition are the same thing. But in user scale it is still about 1/5 of Engine Sim's (Play 66k vs 327k), which shows visuals alone haven't pulled the category leader's users over.
6. Visibility and copycats
- Visibility: it's circulating in small circles. The founder posted "2 days, 4,600 downloads" on Threads (2.3K views), and the GeekNews post got 3 points. No revenue figures are public, X turned up no discussion (x-radar had no results in the last 60 days), and there's no press coverage.
- Copycats: lots of people already build in this category at the same time (Engine Simulator / MUHAMMAD SAAD ATA, Simulation Moteur, Engine Maker, enginesimulator.app, web versions, and Car Engine Simulator 3D on Android). One built specifically to copy Groundcode's "3D cutaway" is suspected to be net.kilho.enginesimulator (launch date unverified). Groundcode itself is copying the same playbook to 「무기 시뮬레이터 3D」 and 「킥플립 시뮬레이터」 (Weapon Simulator broke into the top 100 via Reddit).
7. What's worth borrowing
- Pick categories where playing it out loud is the hook: engine roars, gunshots, skateboards. These sights and sounds are short-video material on their own. The developer's own account posts "what's new in this version" every 2–3 days, turning user wishes into topics.
- One web stack (React/Three.js/Web Audio) ships to mini-apps, web, and native shells: validate on mini-app platforms inside super-apps like Toss first, then go to the stores.
- Rewarded video unlocks a 24-hour single-item use: more natural than a global ad-removal purchase, and well suited to collection-style content (engines, guns, cars).
- 17 languages plus localized store names let it chart on the entertainment lists of many small countries at once.
- Turn the same playbook into a matrix: finish engines, then guns, then skateboards.
8. What's still uncertain
- Paid ads (Meta / TikTok / Apple Search Ads): no evidence found, not tracked in the library.
- Ad revenue: not public. Much of its traffic comes from low-eCPM small countries and the Korean Toss channel, so it's probably not high.
- Toss mini-app usage and revenue: no data.
- Retention: no content loop (no progression, no tasks), so retention may be worse than Engine Sim's; the library has no review samples to check.
- Whether net.kilho.enginesimulator is a copycat or an independent project launched at the same time: not verified.
Sources
- Apple lookup: itunes.apple.com/lookup?id=6814764131&country=us (plus kr/jp/de and 36 other storefronts, 2026-11-06)
- Developer's app list: itunes.apple.com/lookup?id=1835580242&entity=software
- appstore library (agent-im machine): app_profile / app_day (2026-10-28 to 11-06)
- googleplay library app_profile (2026-11-06)
- Groundcode website: groundcode.io/ko, groundcode.io/ko/projects/engine-simulator, engine-simulator.com/en
- Threads: www.threads.com/@groundcode.io (4,600 download post, GeekNews post, Reddit post)
- GeekNews:news.hada.io/topic?id=34886
- TikTok (TikHub): @baechoo24 profile and posts; search "engine simulator 3d" and "엔진 시뮬레이터"
- Instagram: www.instagram.com/reel/DdrPl4wT4Y3/ (Opus 5.5 intro video), www.instagram.com/reel/Ddp3UFwhqSv/
- Engine Sim:apps.apple.com/us/app/engine-sim-sound-simulator/id678744304… ,takasawadynamics.com/engine-sim/
- enginesimulator.app;realenginesimulator.com;AppBrain net.kilho.enginesimulator