I Built A Car Accessory As A Side Hustle And Generate $35K/Month

Published: July 22nd, 2023
Jure Sotosek
Founder, WrumerSound
from Ljubljana, Slovenia
started June 2022
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Hello! Who are you, and what business did you start?

My name is Jure, and I am the founder of WrumerSound. Our company specializes in a product called Wrumer, which is a device that connects to a car's OBD2 port. Through this connection and an App, it simulates engine sounds through the car's speakers.

Starting a business had always been a dream of mine, but finding success was challenging. However, after several years of trial and perseverance, I achieved a breakthrough.

Approximately a year ago, I developed Wrumer and built an e-commerce brand around it. It is now consistently doing $35k in monthly revenue and growing!


What's your backstory, and how did you come up with the idea?

I am 24 years old and have been passionate about software development since I was 12 when I first started dabbling in iOS development. Over the years, I have worked on various apps, websites, and SaaS products, getting my first job in a start-up at 19. Currently, my day job is as a software engineer at a big-tech company.

Starting WrumerSound was a combination of personal experience and outside inspiration. Before WrumerSound, I struggled with my ventures despite performing well in roles at other companies.

A notable shift occurred in Spring 2021 when I developed a Shopify store for an e-commerce brand. Through this experience, I observed the significant impact of effective marketing on the success of e-commerce businesses.

It made me realize the importance of marketing as an integral component of a business strategy. As a software engineer, I had previously underestimated the role of marketing, believing that product quality alone would attract customers.

My initial reluctance to acknowledge the importance of marketing was largely rooted in anxiety and an unwillingness to venture into unfamiliar territory.

The specific idea for WrumerSound came to me when I was purchasing a used car and used an OBD2 diagnostics device. I noticed that the device had access to the car's live RPM data. I realized I could develop an app that utilizes this data to simulate realistic engine sounds, and I decided to build an e-commerce business around it.

Recently having recognized the importance of marketing, I made a conscious decision to approach WrumerSound differently from my past ventures. I resigned from my job to focus on developing the product and, importantly, making marketing a central element of the strategy from the outset.

Take us through the process of building the first version of your product.

While developing the initial version of Wrumer, I focused on creating a true Minimum Viable Product (MVP), ensuring that no extra features were included before market validation.

Wrumer consists of two components - the device and the accompanying app.

The device serves as an interface between a car and a smartphone. It is an off-the-shelf product, so no development was required here. The primary challenge was identifying a suitable manufacturer for the device. After an extensive search on Alibaba and ordering around ten samples from various manufacturers, I selected one that met the quality standards.

With my low order quantity, I could not get custom packaging made. To work around this, I ordered 100 units and did the rebranding myself. I designed the stickers using Figma, ordered them from Sticker Mule, and manually replaced the original branding by sanding it off and applying the new stickers. Though time-consuming and not scalable, this was a necessary step in the initial phase.

Me sanding and rebranding the first 100 Wrumers:


Regarding packaging, I ordered jewelry boxes from Amazon and commissioned custom foam inserts from a local manufacturer. Additionally, I created a user guide in Figma, which I printed using my home printer.

These steps, though unconventional, were pivotal in setting the foundation for Wrumer and ensuring that the product was market-ready quickly and with low costs.



The creation of the app represented the most substantial technical challenge in the development of Wrumer. While my background was primarily in web development, my experience in app development was limited. To bridge this gap, I opted to use React Native, which enables the development of native iOS and Android apps utilizing web technologies.

A particular hurdle was the integration of the audio engine within the app. With limited knowledge in this domain, I had to do a lot of research to figure out. My search led me to FMOD, a sound effects library used by car simulation games such as Assetto Corsa for rendering realistic engine sounds.

The first version of the app:


For the online store, I used Shopify since that is what I was familiar with. I used a local third-party logistics (3PL) company for fulfillment.

Describe the process of launching the business.

The initial launch of the business was underwhelming. I had planned to focus on marketing but was so busy with the development that I only started focusing on it after the launch. Initial marketing efforts included posting on YouTube, Reddit, and car forums, which generated interest but did not result in any sales.

I invested in Facebook Ads, spending around €500, which led to the first two sales. It was clear this was nowhere near profitable, and I had to find another way.

A minor breakthrough occurred when a post about Wrumer in a developers' Facebook group gained traction, resulting in 10-20 sales.

The Facebook post:


Additionally, I made a few TikTok videos that went mini viral and added another 10-20 sales.

The TikTok:


Six months into the project, with around 30 units sold, I pursued a different marketing strategy: outreach to car magazines and portals. I compiled a list of local car journalists and reached out to them via email. The positive responses and subsequent coverage helped me sell out the first batch of 100 Wrumer units.

Feeling a sense of momentum, I decided to take a leap of faith and placed an order for 1,000 units with custom packaging.

The breakthrough occurred while waiting for the shipment of 1,000 units. Analyzing the potential impact of viral content based on prior experience with TikTok, I reached out to approximately 100 car content creators for potential collaboration.

One of the partnerships resulted in a video that garnered 2.6 million views, driving around 15,000 visitors to the website and resulting in approximately 150 pre-orders. This moment was a turning point and confirmed the potential of Wrumer in the market.

The TikTok that went viral:


Stats from that video:


Since launch, what has worked to attract and retain customers?

Our primary marketing focus has been on short-form content, particularly on TikTok, Instagram, and Facebook. We’ve experienced significant success with several videos going viral across these platforms. However, we have yet to gain traction on YouTube shorts.

Here are examples of videos that went viral:

TikTok: (4M views)


Instagram: (5M views)


Facebook: (2.8M views)

It was especially surprising to see the level of virality achieved on Facebook, considering content was posted from a new account.

In addition to social media, we have also collaborated with YouTubers who have integrated Wrumer into their content at no cost, which contributed to sales.

Furthermore, we implemented an Affiliate Program that enables individuals to earn commissions by promoting Wrumer. While this has seen some success, it has not matched the levels achieved through our social media channels.

How are you doing today and what does the future look like?

Moving forward, we plan to maintain our emphasis on social media and short-form content. One specific initiative we are exploring is the localization of our top-performing videos by translating them and publishing them on language-specific channels.

Example of a TikTok translated to German:


Additionally, we are revisiting paid advertising by leveraging our most successful organic videos and analyzing the outcomes. While the results are marginally profitable, there is room for improvement.

We also want to expand our offerings by introducing upselling options, such as more sounds, and developing additional applications that integrate with the OBD2 port. A diagnostics app is one potential avenue we are considering.

Through starting the business, have you learned anything particularly helpful or advantageous?

A primary takeaway from this journey is the importance of marketing in driving a business forward.

I could never have imagined the various unexpected responsibilities and hurdles that arise in the early phases of a business. A prime example was the manual labor I had to put in to rebrand the devices myself.

Moreover, this experience has proven the importance of perseverance and patience, as traction can sometimes take longer to materialize. Compared to past endeavors, where I may have been discouraged by the initial lack of sales, this venture has shown the value of not giving up.

What platform/tools do you use for your business?

The most notable tools we use that I haven’t mentioned already are Slack for communication and Intercom for customer support.

What have been the most influential books, podcasts, or other resources?

I find a lot of inspiration from Starter Story. I especially love the YouTube videos. They give me the motivation and inspiration that great things are possible.

Advice for other entrepreneurs who want to get started or are just starting out?

It’s essential to be willing to get out of your comfort zone. My initial reluctance to acknowledge the importance of marketing was largely rooted in anxiety and an unwillingness to venture into unfamiliar territory.

Additionally, maintaining consistency and focus is critical. Success is often a result of persistent effort, and it’s important to remember that the only definitive failure is when you give up.

Are you looking to hire for certain positions right now?

We are looking for people who see potential in the product and believe they could market it effectively. Sign up at our affiliate program.

Where can we go to learn more?

If you have any questions or comments, drop a comment below!

Jure Sotosek, Founder of WrumerSound
Pat Walls,  Founder of Starter Story
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