The engine is a vital part of the go-kart. It provides the speed and power to move forward quickly. As with anything else on the go-kart, we want to have the best tools in our arsenal. For the TAG Category, two of the most popular manufacturers are Rotax and IAME. Their models, namely the Rotax 125 and the IAME X30 respectively, have brought many drivers to victory lane, and they can do the same for you if you choose correctly. With that, here we will compare what both engines can offer so that they can help you decide what’s best.
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Rotax
As stated by Rotax themselves, the company dates all the way back to the 1980’s making motorcycle engines. They would proceed to cross these engines over to go-kart racing and refine the engine for grassroots motorsports.
When it comes to the specifications, the Rotax runs a fixed jet carburettor which cannot be changed when driving. The jet can be found in the carburetor which allows a certain amount of fuel to flow through. These holes, aside from allowing fuel to pass, also help regulate the fuel flow. This fuel is then mixed with the air which becomes the power that runs your engine. The main jet is mainly for the top-end performance of the engine. Drivers & mechanics can also adjust the needle clip height which is underneath the screw top on the carburettor. This is more to adjust the initial acceleration when the throttle is cracked open in the carb. Another thing to take note is that the Radiator is on the side of the Rotax engine which can be seen in the image below:
The Radiator is basically the part of the kart that cools the engine and prevents it from overheating. Therefore, with Rotax having it near the power source which is the engine, this can help speed up the engine cooling process.
The RPM limit on a Rotax is around 14,200-14,400, making it able to reach top speeds of 70+ MPH or 115km/h depending on the gear ratio you use.
Another strong point of the Rotax is the mid range in terms of how the power is delivered. This makes the engine really powerful around medium-speed corners. What it lacks in initial acceleration compared to the IAME X30, it picks up in the mid-range. Long straights can be a downfall of the Rotax.
All in all, the Rotax is a good candidate for your go-kart, especially if you are on a budget, as the time required between engine rebuilds can be up towards 20 hours. With good midrange and reliability, it is a credible engine that can bring you to the front of the field.
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IAME X30
Known as “The Heart Of Kart”, the Italy-based manufacturer made it start slightly earlier than Rotax, that being in the late 1960’s. With over 50 years of experience under their belt, they have pretty much perfected the go-kart engine, and continue to pursue the excellence they live by.
Comparing it to the Rotax is hard as they both have their advantages and disadvantages. The carb on an IAME is tuneable. So drivers are able to adjust both the high & low-speed jets while driving on track to suit the change in weather conditions and to maximise performance. Next, the radiator is on the opposite side of the engine which can be seen here:
As you can see, the engine is on the right hand side whilst the radiator is on the left and opposite side. The radiator is also substantially bigger than compared to the Rotax, which can mean the engine package may be slightly heavier.
The IAME X30 has a higher rev potential, peaking at around 16,300. Because of this, the X30 has more top end, which is beneficial for tracks that feature long straightaways. Furthermore, it also proves to be faster than the Rotax on the Bottom end of rev ranges. This means that the engine is a force to be reckoned with in the low speed corners as well.
Overall, the IAME X30 is an easier engine to drive, as racers are able to just stamp their foot on the throttle, whereas the Rotax drivers need to be much smoother on their throttle application. This is due to the design of the carburettor and how the fuel is delivered. With more initial acceleration, and better in the top end, the X30 can be advantageous depending on the circuit layout.
And that concludes this article on the Rotax vs IAME X30 debate. Both are great engines that excel in different areas. We hope that this can help you make the right and informed decision in regards to what engine is best for your karting needs and what can bring you to the checkered flag first.
Beyond this however, it is important to match your fast engine with fast driving skills. And for that, Kart Class has the program just for you! Led by 18-time Australian Kart Champion Dave Sera, Kart Class’ Setup Program means you’ll have all the necessary tools to perform on raceday.