Polaris Liberty 800 Dyno-Tested

We received a late-release 2008 Polaris 800 IQ in time to put on 200 miles last spring. All summer it sat in the storage bin on queue for this season until we hauled it to Straightline Performance Inc. (SPI) in Forest Lake, Minnesota, to put the mighty 800 Liberty on the company’s dyno.

After Polaris claimed 154 hp from the Liberty 800 when introduced last year, we measured a peak of 144.9 hp at 8000 rpm. After more phone calls and validation from other sources and dyno shops that found similar results, we believe our numbers are accurate.

Unfortunately, it looks like history is repeating itself. When the Liberty 700 was unveiled in the 2007 Dragon, we sang praises of the engine’s power. Once the snow was on the ground, Dragon 7s didn’t meet expectations. Polaris might have to deal with another batch of riders whose sled doesn’t measure up. We wrote previously that the 800 Dragon has the strongest 800-class twin. On paper, the production machines don’t measure up to our claim.

We asked Polaris why there was such a large discrepancy. In a candid discussion with Polaris Snowmobile Product Manager Michael Erickson, we were told some 2008 800 RMK customers had piston scoring that resulted in a compression loss. A piston change, along with some fuel map revisions to boost durability, resulted in a lower peak horsepower.

Erickson told us that Polaris engineers reported a slightly longer break-in period with the revised Liberty 800, too. While not disputing the peak horsepower number we found, he said Polaris expects peak power in the 149-150 hp range. With just a few tanks of gas through our machine when it was on the dyno, we hope that after some more miles our 800 IQ will gain a few ponies.

On the spring rides with our production 800 Liberty, it felt as strong as expected. Polaris engines make great mid-range power, are trail-friendly and they run well in the field. That was the case of the 700 Dragons, and we think that, too, will repeat. Under ideal conditions horsepower will increase, but not to the advertised spec.

Owners won’t get all the horsepower they believed they were buying, but they’ll be getting a powerful sled with a great mid-range rush. Owners can purchase an EFI fuel controller and, according to DynoTech’s Jim Czekalia, modify the fuel map to reach the 154 hp claim. But altering the factory fuel setting will nullify the warranty.

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