CL1 Jr. Dragster Support

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CL1 Jr. Dragster FAQ

How does the CL1 Junior Dragster Kit differ from standard data acquisition kits?

Mobile technology and cloud data. Standard data acquisition systems utilize an on board data recorder, be it a data recorder and separate digital dash, or a data recorder dash. Information is saved and downloaded via either a removable memory card or download cable, to a PC. This method is dated, limiting and time consuming, requiring manually moving data files between multiple PC’s for viewing, using 1990’s era windows based software for programming and analysis and more importantly, not taking advantage of the mobility aspect of modern day mobile devices and cloud technology.

The CL1 Junior Dragster kit utilizes a vehicle mount mobile phone, running Racepak’s propriety D3 app and a vehicle mounted CL1 data box, to transmit sensor data via Bluetooth, from the CL1 to the mobile phone, for instrumentation, data recording and automatic uploading of data to an optional cloud account, for remote data review, on an internet connected device, anytime, anywhere in the world.

So how does the CL1 actually work?

At the very basic level, a CL1 data box is mounted on the vehicle and connected to external sensors (temperature, pressure, rpm, etc.). A mobile phone, running the D3 App, is installed in the vehicle. The mobile phone then receives sensor data from the CL1, via Bluetooth, displays pit and engine information, uploads data via the cellular service of the phone to an optional cloud account and can also function as a data analysis program.

Why use a cell phone for this purpose?

Very simple. Modern cell phones are more rugged, have far superior displays, processing power and wireless capabilities than data logging or display devices currently on the market. They are designed for constant abuse by the consumer, have incredible technical capabilities and the costs to duplicate their properties for data acquisition purposes would be astronomical.

Is the vehicle mounted phone GPS used?

NO. The CL1 data box contains an onboard 20 Hz GPS system, along with an external GPS antenna, providing highly accurate data for the D3 app.

What is the D3 App?

The D3 app combines instrumentation, data recording, data analysis and device programming into a single location, on the vehicle mounted mobile phone.

Why do you call it a data “box” and not a data “recorder?”

The CL1 is merely a collection point for all external and internal sensor data, which is then wirelessly transmitted via Bluetooth, to the vehicle mounted phone running the D3 App.

How many data channels can the CL1 input?

8 external sensor inputs. There are four external sensor connectors on the CL1, each user programmed as an analog and RPM input.

How can I input eight sensors if there are only four sensor inputs on the CL1?

Racepak provides an optional analog/rpm splitter, enabling the input of one rpm, one analog sensor per input

What are the sample rates for the data channels?

User defined from 1Hz to a maximum of 50Hz, per data channel

What comes with the CL1 data kit?

The CL1 data box, GPS antenna, three rubber mounting feet, four AA rechargeable batteries, USB charging cable and adapter, Engine/RPM harness, inductive rpm wire and mobile phone mount.

How is the CL1 data box powered?

Four rechargeable, Ni-Mh, AA batteries.

What about battery life, as I don’t want to charge the box after every run.

No need! The CL1 has an advanced energy management plan, which keeps the box in sleep mode until an Engine RPM signal is detected. After a short period of inactivity, the box will return to sleep. A typical junior dragster day will use less than 20% of battery life

What about phone battery life, on the vehicle?

The D3 app also contains a sleep setting, allowing the phone to sleep until the CL1 data box awakens (from the tach signal) which then awakens the D3 app and phone. This function is optimized for Android devices, while IOS devices are not optimized for an external wake up signal. Instead, the D3 app can just be quickly tapped, bringing the app from sleep.

What sensors can I connect to the CL1?

Racepak offers a complete line of RPM, pressure, travel, temperature and air fuel sensors.

Can I connect my own sensors?

Yes. If you know the calibration values for your RPM or analog (0-5V) sensors, Racepak offers an unterminated sensor cable (CL1 mating connector installed, no connector on the opposite end) which the user can install the mating connector for their sensors and connect to the CL1.

How are sensors programmed?

From the Settings icon on the homepage of the D3 app. remember the phone functions as the data recorder, so no need to “send” programming changes to the CL1 data box.

Does the CL1 data box utilize internal G meters?

No. The processing properties of the D3 app and mobile phone provides highly accurate lateral and accel g data.

What type of Bluetooth is used between the CL1 and the vehicle mounted mobile phone running the Racepak D3 app?

Low energy Bluetooth (BTLE) as it has proven to be highly robust and dependable in a variety of conditions. Remember, the onboard mobile phone is only receiving data from the nearby mounted CL1 data box, so there is no need for long range Bluetooth capabilities.

Do you trust a mobile phone to survive the racing environment?

Yes. Consider the demands placed on a consumer electronic device, which typically lives in our pockets and is subject to constant abuse. Water, heat, cold, sand, dirt. Constantly taken in and out, turned off and on. Subject to continual drops, slips, and g forces and they typically continue to work

Will it work on Android and IOS?


What mobile devices do you recommend?

View our Mobile Specifications Sheet here.

What happens if I do not have cellular service on the phone? Can I still have a cloud account?

Yes. Since the phone functions as the data recorder, all data is stored locally on the phone. If the phone has Wi-Fi capabilities, as soon as the phone can access a Wi-Fi network, data is automatically uploaded to the customers optional cloud account.

How much is the cloud account?

It varies by the number of users. The account holder plus two remote user accounts is $9.99 month / $100 year.

Why do I need to register the CL1?

In order to associate your CL1 with you, your team and remote users, the CL1 utilizes a unique serial number that must be registered before first use. This not only links your CL1 to your account, but to the vehicle mounted mobile phone, while also securing your account.

Where to I register the CL1?

Go to and follow the online prompts.

Can the Bluetooth fail to connect from electrical interference?

We have not found any issues with connectivity, at this time.

Why should I trust Racepak’s cloud service?

Racepak’s cloud service can upload and live stream data and has been tested with thousands of users, with no issues. Our software team has extensive experience in both the gaming and cloud industry, providing the most rugged, reliable and secure motorsports cloud data service, in the industry.

Where are the Racepak servers located?

Racepak’s dedicated servers are located in the United States and hosted by one of the top ten cloud service providers, in the industry. This ensures reliable, 24-7 service with redundant backup and security measures for all your data.

Can you lose my data?

While no technology is 100% fool proof, the hosting company selected by Racepak is ranked within the top 10 for cloud providers, servicing a number of Fortune 500 companies. Your data is in good hands.

Can more than one person remote view my data?

Yes. Depending upon the optional cloud program chosen during the CL1 registration process, anywhere from 1 to 100 or more can view your data.

How can other remote viewers not see my data?

Only authorized remote viewers, with a unique passcode, can access your data.

Where do the Google overlay track maps come from?

Racepak has pre-loaded more than 2000 worldwide track maps into our map data base, providing simple and automatic overlay.

What starts data recording and uploading to my cloud account?

When the vehicle exceeds 11 mph / 5 ms and Engine RPM is detected, data transmission is initiated.

Can I use any phone on the vehicle?

The short answer. Yes. The key area is display brightness, or Nits. A list of technical specifications can be found on this website.

Can I use any tablet for remote analysis?

Yes. As long as it has working Wi-Fi. We recommend any of the Samsung or Apple products.

Can I use a phone for remote analysis?

Yes, remember the D3 app provides the same analysis functions regardless of the device on which it is installed.

Can I use a tablet on the vehicle?

Technically, yes. The challenge is size and mounting. If the table has active Bluetooth, you could pair with the vehicle mounted CL1 data box. You would not have data cloud upload, unless the tablet has cellular service. However, once connected to Wi-Fi (such as in the pit area) it will automatically upload data from the just completed outing.

What happens if I uninstall the app from the mobile phone?

If a cloud account is active, the data remains saved on the cloud server. If no cloud account is active, then all locally saved data on the mobile phone, is lost.

How does the data analysis differ?

As the D3 app is designed for use with mobile devices, all the intuitive actions such as touch, swipe and pinch can be utilized. In addition, the superior resolution capabilities of modern tablets exceeds the capabilities of most laptops and PC’s proving greater detail.

Is the same D3 app used for the vehicle mounted mobile phone and the tablet used for remote viewing?


What about firmware updates?

Automatic. When the vehicle mounted phone and CL1 data box powers up, the CL1 data box is “checked” by the D3 app for the latest software version. If a newer version is detected, it is automatically installed and the viewer notified of the current installation action.

Is the D3 app available on Google Play and the Apple store?


How do zero a run

No need. The D3 app automatically zeros the run, displaying data 1 second before the start, until the vehicle comes to a stop.

What starts data recording and uploading to the cloud?

When the vehicle exceeds 11 mph (5ms) and along with a working tach signal, inputted into the CL1 data box.

What if my track is not in your database?

No problem. The D3 app will still utilize Google maps when overlaying driving data. The map will be zoomed out more than if Racepak pre-mapped.

Where can I find Racepak’s list of track maps?

Support / Available Maps, on the CL1 landing page.