The Big Dogs Dyno Up

The Big Dogs have more in common with each other than you might expect
Turns out that the Big Dogs- stock sleds with the biggest engines and greatest amount of performance- have more in common with each other than you might expect. When it comes to 600s and 700s, their identity is based on sheer performance and each sled brand seems to counter another competitors' top model.

With the four Big Dogs -in this case, Arctic's ZR900 twin, Polaris' XC SP 800 twin, Ski-Doo's REV 800 HO, and Yamaha's unique four-banger- there are some major choices to be made when making a purchase decision.

On the dyno, the Cat 900's 151.1 horsepower at 7200 revs with 110 foot-pounds of torque leaves little question as to which sled is Top Cat. But with 140 horsepower and a linear torque curve, Yamaha's four-cylinder, 1000cc, four-stroke engine is a marvel. The choice between the two is amazing. The Cat is brute force and zero subtlety. The Yamaha is new technology for sleds, turbine smooooth performance, and two extra cylinders and valve train of weight. The Polaris and Rotax fit in between these two.

The Polaris engine is a wonderful "Made in the USA" Liberty twin with cylinders slightly less imposing than the ZR900 and horsepower akin to the Yamaha four-stroker. By the numbers you're looking at 140-hp, 96-lbs-ft of torque coming from 7700 revs per minute. Ski-Doo's engine company antes up good performance in this class as well with 140 horses and 94 lbs-ft of torque at a similar RPM.

The bottom line is simple. Three of the four Big Dogs are incredibly similar in output. The Top Cat leads the way in performance. And, as you might have expected, as wonderfully clever as it is, the Yamaha one-liter four-stroke needs an extra 200cc to compete favorably against the 800cc twins from Polaris and Ski-Doo.
Now the choice is complicated. Weight, as in power-to-weight, is a consideration. The Yamaha four is a more complicated mass of valves, cams, etc. Added weight is a given versus the two-strokers.

Based on last year's Shoot-Out numbers, each horsepower from Yamaha's four-stroker had to pull more than 4.6 pounds (less rider weight). The Ski-Doo and Arctic Cat pulled slightly more than 3.8 pounds each, while each Polaris pony pulled just less than four pounds of sled weight.

Based on reality, when making a decision to buy a Big Dog (or, Cat!), you need to consider more than dyno numbers. Two or four cylinders? Two or four-cycles? Power-to-weight? And those are the easy questions.

This story ran in the February 2004 issue of American Snowmobiler magazine
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