Every now and then a snowmobile manufacturer will release a new sled with little to no warning, surprising everyone.
This was exactly what happened with the brand-new 2018 MX Z 600R from Ski-Doo. This
is a limited-build late-release model that introduces the all-new Rotax 600R E-TEC engine fitted into the REV Gen4 platform. This is Ski-Doo’s very first 600 engine in the narrower Gen 4, which should be a huge hit with trail riders everywhere.
Why is it being called a 2018 late-release instead of a 2019 early-release? It seems like it could go either way, but it depends on the exact build date of the machines. These sleds were manufactured in December of 2017, so they can not be called a “2019”. Not that it matters, but it is curious.
As is the configuration. Looking at the machine’s features, specifically the shock package, you’d swear it is an MX Z X-RS. Multi-function gauge pack, rack steering, Quick Adjust rMotion with a KYB Pro 36 in the rear and adjustable KYB Pro 36 R piggyback front shocks all scream X-RS. It is highly unusually for Ski-Doo to offer a sled with these features mid-season, as they typically reserve this kind of hardware for Spring-only buyers. But that’s the golden nugget – since you can only buy an X- or X-RS package in the Spring, this new sled had to be simply an MX Z, not an X and not an X-RS. Kind of a wolf in sheep’s clothing, if you will.
We were stoked to find this sled fitted with the Quick Adjust rMotion in the rear, minus the adjustable Pilot TS skis up front. Instead, the MX Z 600R is fitted with the familiar Pilot 5.7 skis which we have found to provide great handing across a wider range of snow conditions. We also like to add the extra set of runners to the outside edges of these skis for improved durability, especially in a year like this with mostly all lake effect snowfall and little system snow where we do most of our testing in the U.P. of Michigan.
The All-New 600R E-TEC
Despite the chassis and suspension configuration, the attraction and primary point of interest for most will be the brand-new 600R Rotax E-TEC engine. Our beloved 600 E-TEC engine that came out in 2009 has been in production for ten full model years, so it was due time to bring a replacement to market. The catalyst of course was to have a new engine that was narrow enough to fit into the sleek Gen 4 platform, as this is the main reason we have only been able to get Gen 4 sled with an 850 E-TEC, until now.
As wonderful as the 850 E-TEC engine package is, it was designed first and foremost for the power-robbing higher elevations of the west. Down at lower elevations many riders have found it has what could be described as excessive power, excessive torque and almost scary fast acceleration. Really? Yes, really. The 850 is a wicked-fast & wicked-strong engine package, and not everyone wants or needs that kind of excess. It has an appetite for fuel, oil and drive belts, and costs a fair chunk of change. Mere mortals who wanted the Gen 4 platform and the agile handling it provides have been waiting for a lower-powered version, one that wouldn’t get them into so much trouble so quickly. We all knew it was only a matter of time, and when Ski-Doo released their 2018 race sled fitted with a mono-block 600 E-TEC engine, we could see the future right there in front of us. This would be the basis for the next-generation 600 E-TEC from Rotax.
SnowTech editor Kevin Beilke visited the Rotax engine factory in Austria back in October while they were building the very same 600R engines that are fitted into this new sled. He witnessed first-hand the assembly process and was able to speak with the engineers and technicians responsible for this new design, able to learn about the features and benefits that were built into this package.
This is what he learned. The new 600R shares much of the same design features as the 850 engine, namely the narrow compact design. A key element of this is the monoblock cylinder design, meaning there is a single block for both cylinders instead of two individual cylinders. What this does is allow the “airspace” between the two cylinders to be used as larger transfer ports, thereby increasing total airflow capability. Like the 850, these are plasma-coated cylinder liners, using a 6-layer process. The plasma coating provides incredibly durability to the cylinder walls, improves heat transfer and offers excellent oil retention due to its porosity as it holds the lubricating oil like a sponge. The monoblock cylinders will also stay closer to perfectly round for a longer period of time, thanks to the rigidity and improved heat transfer.
The 600R engine is aimed at improving overall reliability over the previous 600 E-TEC, as that is what the “R” stands for in the name 600R – reliability. The Rotax team worked on improving the cooling in the head and cylinders, as well as around the spark plug. That said, this engine does not have a liquid-cooled crankcase as it is not needed at this power level. Rotax engineers assured us the main bearing temperatures are perfectly acceptable at this power level without a liquid-cooled crankcase. The PTO bearing is now located 5mm further out for improved support, and the crankshaft is now indexed to the improved pDrive primary clutch (now with improved cooling capability). We’re told it still uses Isoflex lubrication, and that the heavy-duty oiling system of the 850 is simply not needed at this reduced power level (40HP less than the 850).
Power? Peak power is said to be 5 HP more than the 600 E-TEC, now up to the 125 HP level but with more torque all through the RPM range, and all with no increase in fuel consumption meaning it is all done more efficiently.
While many riders might not notice the extra power, what they will instantly notice is the improved dynamic response – how quickly the power is delivered when you crack the throttle. It’s not jumpy or on/off power, but it does react to your inputs faster. This is due to the shorter and straighter intake tract and the 850-style reed blocks that are now positioned 30% closer to the pistons. We also find 3-stage eRAVE power valves and a smoother exhaust port transition, again helping to boost power and response. Speaking of boost, there are no boost injectors like what the 850 has. While the 600R shares the same 52mm throttle bodies as the 850, the ports for the booster injectors are closed off as they are not needed to provide extra fuel at the 125 HP power level. In fact, the 600R uses the same E-TEC injectors as the 600 E-TEC engine, perfectly capable of providing all of the fuel required for this amount of power.
The overall engine package is only 1.5 pounds lighter than the 600 E-TEC, up to 3.7 pounds if you include the electric start. Making the engine narrow enough to fit the Gen 4 platform comes from the use of the monoblock cylinder block, and the narrowing of the magneto by 37mm (1.25”).
Those lucky enough to throw a leg over a new MX Z 600R will discover they are riding a confident all-around rough trail performance machine with precise cornering and big bump capability. We have instantly fallen for this new 600R, having ridden it for 500 miles in three days. Without a doubt, Ski-Doo continues to evolve and improve the overall calibration of the Gen 4 platform, something we typically experience with each and every new platform as it usually takes a couple of years to get a new chassis calibrated to true excellence.
With its centralized mass the MXZ 600R responds instantly to the slightest rider input for easy & near-effortless handling. Outfitted with premium KYB Pro 36R shocks in the RAS 3 front suspension and KYB Pro 36 and HPG Plus in the rMotion 129 rear suspension, the MXZ 600R E-TEC is supremely agile and tames harsh trail conditions with ease. The shock package delivers an excellent balance, both comfortable and capable, making this package our favorite MX Z to date. Features such as the rack steering system and Forward Adjustable Riser also help to create a precise, confidence-inspiring ride.
You really don’t notice the extra 5 HP on top all that much, to be honest. Instead, what you really notice is the dynamic response. The sled and engine is quick to respond, extremely smooth and linear in power delivery, with clutching that allows the 600R to spin up above 8,000 RPM almost effortlessly. Acceleration is smooth and fast, but the package doesn’t seem to be as “electric” in nature or as quiet as the 600 E-TEC. Rather, there is a bit more growl or throat to the sound, with a slight resonance at around 6,500 rpm. Nothing annoying, but if you are super familiar with the 600 E-TEC you will notice this engine does talk to you a slight bit more.
Once the break-in period is over, the 600R is very competitive with the 850 for a long ways into a pull. Our riders found it to be extremely fun to ride, not so intimidating, and seemingly more playful in that we could ride it with more enthusiasm and not have to be so extra cautious as one needs to be with the 850 that can be so excessive at times. Some riders like to have all of the power of the 850, but the masses will certainly appreciate the 600R as the better trail riding package. Even though the total machine weight is likely very similar, when you ride the 600R it gives you the perception of being significantly lighter than the 850. We really like it, and think you will be as happy with it as we have been.
The 2018 Ski-Doo MX Z 600R is available in limited quantities right now at Ski-Doo dealers for $13,199 USD.
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