Under Review | The new IAME KZ, more low-end power

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THE NEW IAME KZ, MORE LOW-END POWER

Carlo Forni

16 March 2016

TYPE
Like most kart engines on the market, the RKZ is a 2-S. 4-stroke engines are still a small niche

125 CC

DISPLACEMENT
125 cc has been the standard for some time now, while in the past it used to be 100 cc

PUSH

START
Push-mode as in all KZ engines, with hand-release clutch and neutral to 2nd gear shifting

GEARBOX

TRANSMISSION
The RKZ belongs to the gearbox “family” of karting engines.
It has a 6 gear manual transmission

HOMOLOGATION
Certified under KZ homologation, just renewed and valid for the next 9 years, beginning in 2016

IAME is a specialist engine manufacturer and the most famous engine company in the karting industry, thanks to its long, distinguished history. It is proud to introduce its new engine in the Parilla Screamer 2 Shifter classes. Let’s find out more

The Parilla Screamer 2 by IAME includes modifications to almost all the components of the previous model, particularly in the cooling system. Our analysis begins with the cylinder head, which now consists of three pieces, all machined from a solid block: the outer cover, the body of the head and the actual combustion chamber itself. The outer cover can is easily removable from the other two elements, which are assembled together by force. The solution with a two-piece head is also approved and can be used. The head cooling system is now more efficient, especially in the area below the spark-plugs, thereby improving low-end acceleration. The previous solution, with a portion of the head obtained by casting, resulted in a hotter area and greater thrust at strong>high revs after the maximum point of power, commonly called “over-revving”, but less low-end power. Indeed, the cylinder and the head need cooling, within certain limits and, depending on how and how much this is done, there is an effect on reliability, as well as performance.

The new cylinder head consisting of 3 components: a cover and a two-piece head. This reduces costs should it become necessary to replace parts due to damage inside the head

Above, the lower slots of the cylinder have been enlarged compared to before. Below, a detailed photo of the cylinder and head coupling using 6 screws and the liner completely detached from the upper part of the cylinder

Above, a resin conveyor (“Factory Kit” version) and an aluminium one. Below, the coupling point of the gear selector, which has been shortened to make the engine more compact and adaptable to any chassis.

The goal of the new KZ engine by IAME KZ was an improvement to low-end power, to increase drivability. An increase in the diameter of the lower cylinder slots, through which the water passes, provides greater cooling of the exhaust system and further optimises performance at low and medium revs. Speaking of the cylinder and the head, now the coupling has 6 screws, instead of 5, while the liner is completely detached from the upper part of the cylinder, ensuring more room for expansion when the engine becomes hot and avoiding critical deformations and tension of the metal. The cylinder can therefore expand more uniformly with the piston at the different temperatures of engine operation, to the advantage of the tolerances between the two elements. This is an important aspect, given that the cylinder tends to cool down more at the front due to the air flow when the kart is moving. The new Screamer 2 is also available with the Factory Kit, an advanced solution compared to the Standard version, with more of an effect at higher revs and greater potential in terms of performance.