The Vortex Mini Rok engine is a very popular choice when it comes to the younger generation of drivers. This engine is ideal for beginners who are new to the sport and to driving as a whole. The speed of the Mini Rok engine is restricted though.
Under ideal conditions, the Mini Rok engine will hit a top speed of 56 mph! This is really quick for a simple 10 horsepower, 60cc engine, but there are many factors that determine this top speed.
In this article we are going to have a look at why this engine is so popular, and some variables that can help you to squeeze out some extra power from it.
Popularity of Vortex Mini Rok
What makes this engine so popular is its simplicity in operation and maintenance. It is arguably a bit easier to maintain than the Rotax engine, which is its main competition. Despite this, the Rotax engine is still more well known in general, and more widely used than the Vortex. This is simply because Vortex is still relatively new to the karting market.
However, when it comes to the Mini class, the Vortex seems to be more popular. This has led to many karting federations around the world using Vortex engines as an entry level series in their national championships.
The Vortex engine is also cheaper than the Rotax version, adding to its popularity as an entry level engine. The Vortex Mini Rok engine will cost you around $1600, whereas the Rotax version, the Mini Max, will cost you around $2500.
The main difference here being the upgrades. The Rotax Mini Max is easier and cheaper to upgrade to junior class than the Vortex version. So, you would really be looking at lower initial buy-in cost, versus lower long-term cost when it comes to moving up to junior class.
Vortex Mini Rok Speed Comparison
There are also some small differences in specifications between the Vortex and Rotax engines. Of course, these engines are hardly ever used against each other in races, but it is still interesting to compare them to see which has the better performance.
First of all, both engines are restricted, since they are aimed towards kids under 12. To start us off, let’s have a look purely at top speed comparisons. Under ideal conditions, the Rotax engine is slightly faster than the Vortex. Rotax will give you a 59 mph top speed and the Vortex will come a close second with 56 mph.
Like we always say though, top speed is not everything. If you only look at top speeds, you’ll most likely end up mid pack. So how does the Vortex compare in other engine departments. Both are 60 cc engines; interestingly however, they differ a lot when you look at the details.
Looking at maximum power, the Rotax tops the Vortex as well. Moreover, the Rotax will hit this peak engine power at an earlier stage in its engine speed than the Vortex. Vortex Mini engines produce 10 horsepower at 11,000 rpm, whereas the Rotax engines produce 13 horsepower at only 7,500 rpm. This means there is more power available at an earlier stage of acceleration for the Rotax.
The Vortex also loses out on the torque that the engine produces. Once again, the Rotax is able to produce more torque at an earlier stage in its engine speed than the Vortex engine. The comparative figures are 13 nm at 6000 rpm for the Rotax, and 6.5 nm at 9000 rpm for the Vortex.
So, if the Rotax is faster than the Vortex, why is the latter more popular for beginners? The Rotax Mini Max is built for kids who already have racing experience. The Vortex engine is better for kids who are beginners and still learning the ropes of racing.
The slower and slightly less powerful engine presents a smaller learning curve for kids, and allows them to quickly become familiar with the speed of a kart and how a kart handles. The simplicity of the engine also allows them to learn more quickly about how it works and how to maintain it.
Vortex Mini Rok Setups
As mentioned earlier in the article, the top speed of the Vortex Mini Rok engine depends on a number of variables. However, as it is restricted, there aren’t many adjustments you can make to the engine. But there are still some setups you can try to improve the speed of your engine.
There are two main adjustments that you can legally make in the engine department to adjust the speed of your Mini Rok engine. The first is your fuel-to-air mixture ratio. This is important because it becomes a big variable when it comes to competition.
Your engine can run either a lean, medium or rich fuel mix. It is mostly affected by the weather conditions and temperatures. Generally, you want a balanced setting, however, in some cases you will need more fuel flowing into the engine, in which case you will set the needle to the rich setting, giving the kart quicker acceleration.
An easy way to check if your fuel mix is balanced is to have a quick look at the spark plug after a run. This is most likely going to be your best option since you won’t be driving the kart. If the spark plug has a black, oily soot on it, then your engine is running too rich.
If the spark plug has a bit of a white residue on it, then your engine is likely running too lean. Ideally your spark plug should be clean and dry, meaning the fuel and air are have the perfect ratio to mix together.
Track layouts also affect which setting you want to be using. For example, if you are running on a circuit with long straights, you will need a lean mixture, which gives the engine more power at higher rpm ranges.
The other adjustment you can make to the speed of your Vortex Mini Rok engine is the gearing. Like the Rotax engines, the Vortex runs a single gear engine. This sprocket can be changed depending on your need for top speed or acceleration.
Larger sprockets have more teeth, and they will give your kart faster acceleration out of corners, at the cost of top speed. The same will be applied the other way around, going smaller in gearing means higher top speed and slower acceleration.
Again, since you aren’t driving the kart, you will need to judge from a third person view whether or not the gearing on the kart is correct. Generally, most other people will be running the correct gearing, or very close to it.
Otherwise you can stand at the end of the longest straight and listen to your karts engine as it comes past. The engine should not be redlining or maxing out at the end of the straight, however it is fine if it comes close to that. Generally, you want your kart to run close to its maximum engine speed at the end of the longest straight.
Furthermore, there are some other smaller variables that determine the top speed of a Vortex Mini Rok engine, however they are less controllable, or have rules which are set in place to control these variables.
For example, the weight of driver and kart will change the top speed of the kart. However, championships have regulations which impose a minimum weight limit to eliminate this variable and create an even playing field.
Vortex Mini Rok Maintenance
Maintenance is key in engine performance. We are going to cover some basics on how to keep your Vortex Mini Rok engine performing at its maximum for every race. Most newcomers to the sport aren’t clear on what they need to do or even how often they need to do it, and this can significantly reduce the performance and lifespan of your engine.
These may sound like complicated tasks to do; however, it is important to remember that you do not need to be a mechanic to service your kart. It may take some learning and studying at first, but once you know what to do, it will become second nature. You can even teach your kids how to clean their own carburettors.
Clean The Carburettor
Firstly, the carburettor is your most commonly cleaned component. It is suggested to do this after every race, so just make it a habit to clean the carburettor first thing when you start working on your kart for the day of testing or racing. It may feel like a long process, but the more you do it, the quicker and easier it becomes.
Lubricate The Throttle Cable
The throttle cable needs to be checked and lubricated after every race as well. This is very important because the last thing you want is for your kid to be in a kart with a stuck open throttle. If the cable frays, it needs to be replaced, however this rarely happens.
Lubricate The Chain
Next, you will need to apply chain lubricant to the chain. Simply spray it onto the chain while turning the rear wheels. This will prevent or slow down wear on the chain while the engine is running. It is advised to replace the chain after 10 hours of engine run time, however, they can last much longer if properly maintained.
Clean The Spark Plug
The spark plug needs to be checked and cleaned after every 5 hours of running, or after every race. Dirt, oil and fuel normally stick to the spark plug and can affect your engine performance. Simply remove the spark plug from the socket and clean it using a metal brush. Replace the spark plug after 30 hours of use.
Clean The Exhaust
Finally, the exhaust usually needs to be cleaned after 10 hours of use. We have covered some top tips on exhaust maintenance here. The exhaust needs to be removed and the inside needs to be cleared of any dirt or burnt exhaust matting.
The Vortex Mini Rok engine is fantastic for beginners. The slower engine speed allows kids to quickly get to grips with the basics of motorsport, and the engine has quickly become a favorite for many.
You can adjust the setup of the engine to determine the top speed that you need to get from it. Remember, top speed isn’t everything! Setup your engine based on what will give you the fastest lap time, not the fastest speed.
I hope this article has helped you to understand the setup of the Vortex Mini Rok engine better, as well as the maintenance requirements for it to perform at top level.