Ski-Doo really had a big task facing them. With the REV taking the industry by storm back in 2003, it had risen to the...

Ski-Doo really had a big task facing them. With the REV taking the industry by storm back in 2003, it had risen to the top of the world and it was five years into its cycle. The other sled makers were catching up, and passing it in some regards, so it was time to once again move the target. But, how do you improve upon it? How do you once again make it bigger, better, and worthy of your consideration?

It’s not like Ski-Doo riders were complaining about the weight of the REV models. About the most valid complaint was that since Ski-Doo had introduced the “rider-forward” ergonomics, the rest of the industry had analyzed the rider positioning and tweaked it so the knee angle wasn’t as tight as the REV. Many of us felt the Arctic Cat F-Series and Yamaha Phazer models had improved upon the REV seating position with a more relaxed knee angle. The key was to keep the hips above the knees so standing was easy, so it could be done using your legs instead of having to bench press your entire body weight with your arms when you wanted to stand.

Ski-Doo had also been watching Yamaha, very closely. They saw how the four-strokes were gaining popularity, and how with each passing year they were getting lighter and lighter. Then, the Phazer and Apex models truly featured rider-forward ergonomics. The four-stroke engines were mighty and very reliable, but they really didn’t have anything over the SDIs in fuel economy.

However, the XP didn’t come about as a reaction. Its development started as soon as the REV itself was validated, so Ski-Doo next set their sights on doing it “right”. The REV was really a stop-gap sled in the sense it was built from a new, solid chassis, but the rest of the platform was using existing components. To go all-new at that time would have been too risky. So, with rider-forward proven, they set out to make an all-new sled with rider-forward ergonomics, but to do it with this in mind from the get-go.

Basically, every part and piece had to reapply for its job. Logically, their engines were a huge investment so they kept them intact, as the next wave of EPA rules wasn’t until 2010, they could use their existing engines for a couple more years. But the rest of the sled was analyzed and redesigned as if they were a start-up company that didn’t have parts bins full of pieces to utilize. This meant new tooling, new parts, new everything. Very expensive and very risky. But, the result would (hopefully) be so impressive it would force the other sled makers to reel.

The Yamahas were getting really close in weight to the REVs, so Ski-Doo knew they could make their two-strokes so much lighter that there would again be a significant weight difference. Ski-Doo asked us how much weight would be a “significant” difference, and we all told them 25 pounds would be huge. So, they aimed for 50. Go figure!
OK, here we go. The new REV XP (eXtra Performance) models are about fifty pounds lighter, across the board. About the only parts left over are the engines, primary clutch, skis, coupler blocks, and maybe the left handlebar control block. Maybe a few bolts here and there, but everything else is all-new.

Not only did they computer-analyze each and every part and make it as light and multi-tasking as possible, they also wanted to re-arrange the components to get our feet where they wanted them. They knew rider-forward was valid, but they also wanted to let us open up that knee angle and get some comfort back that had been lost in moving the rider forward on the REV. With the REV, the secondary clutch and jackshaft was the limiting factor, so this was relocated up and forward so we can now place our feet in this valuable location (right alongside the drive axle). The result is the ability to ride aggressively AND more relaxed, as you can move your feet EIGHT inches further forward than before. No longer are they locked in place.
During the development of the REV XP models, Ski-Doo realized something profound. Their MX Z Trail, the 500SS value sled, was within striking distance of the magical 400 pound mark. They could, with some tricks and lighter parts, make a 500 SS model that broke the 400 pound (dry spec) mark.

Enter the MX Z TNT. It has a dry weight spec of 399 pounds (the prototypes were 392, but they gave themselves a couple of pounds to work with as production seems to add a couple here and there). They started with their rock-solid 500SS engine package (actually the 600 liquid engine that originated with the first ZX Summit 600) and did what they had to make it a jazzed-up version of their MX Z Trail (gas cell suspension 500SS value sled).

The MX Z TNT blows away the competition when it comes to weight. It is said to be 82-88 pounds lighter than the Polaris 500 XC SP, Arctic Cat F5 EFI and Yamaha Phazer. Over eighty pounds lighter. That’s a lot of cheeseburgers.

To offer a 600 liquid-cooled sled at under 400 pounds takes some time to comprehend. The last time we recall such a comparable feat was with the original fan-cooled Phazer that came in at under 400 pounds, but that was like twenty+ (24) years ago.

A sled this light translates to a level of responsiveness only hinted at by snowmobiles of the past. It is almost a telepathic bond between you and the sled that allows for responsive handling that has to be experienced to be understood. You move, it responds. Terms like agility, flickability, responsiveness, lightweight, they all pale in comparison to the reality. It’s like a toy underneath you. You don’t drive it, you ride it. You don’t steer it, you manhandle it. And with your feet forward (but you centered) you can again leverage the chassis with your feet. Maybe they should have called it REV-PLUS.

OK, so we like the TNT. What don’t we like about it? It is a fairly cold sled to ride, as were the REVs. Wind protection is marginal with the minimalist front end. The packaging is very tight, as the mechanics were placed and then the stylists formed the panels around the sled. The stealthy design looks futuristic and fast, even standing still. The diamond-pattern is called “faceted” design.

Our prototype testing of the TNT indicates it is way lighter than anything else in recent memory. The handling is precise, with surprisingly light steering effort for a Ski-Doo. It isn’t what we’d call squirrelly, but it isn’t a sit-back-and-relax cruiser by any means. It requires less constant attention than the first REV models, so most anyone should be able to acclimate to the sled. Hanging on for a long day’s ride doesn’t require as much effort since you don’t have to horse around the extra 80-100 pounds.

Where we noticed the most need for improvement was in the rear suspension. This was true with all of the XP models, in that the new SC-5 suspension wasn’t up to the performance level in prototype form that it should be, so we’re going to have to wait and see what the production sleds work like. With this much of a radical change, it will take some time to get the suspensions tweaked and fine-tuned. It wasn’t until the fourth year of production that the REV suspensions really came into their own, so we’d expect the XP suspensions to get better with each year as well.

With under 400 pounds to haul around, the proven 500SS engine package works very well. This engine still makes about 108 HP, and despite being carbed, our testing has shown it is very close to the 600 SDI in real-world fuel economy, so don’t think the SDI is going to be head and shoulders better than the SS. They’re pretty close out on the trail.

How does the TNT differ from the MX Z Trail (500SS)? The Trail has gas cell shocks, the TNT has HPG Take Aparts all around. The TNT gets taller handlebars with hooks, and a host of lightweight parts from the X-packages that also help shave 16 pounds off, in comparison to the Trail. The biggest difference, performance-wise, will be the suspension calibration, with the TNT more capable through the rough, with the Trail more of a groomed trail sled than a bump sled. The TNT could have been called a 500X, but then it wouldn’t stand out.

Bottom line; the Ski-Doo MX Z TNT is an explosive little rocket that brings back the fun factor of smaller and lighter sleds that don’t break the bank. Whether it is still durable remains to be seen, but we have no reason to believe it won’t be everything that you’d expect. Whether blasting down a forest road, groomed trail, across the lake, or through the meadows, the TNT is going to be one of the hottest sleds of 2008, and yes; it truly has the potential to be bigger than the original REV.
The 2008 Ski-Doo MX Z TNT sells for $7,649.

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