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Now is the time of lightweight big 2-stroke 800 twins. Every OEM, except Yamaha, has several 800cc sleds in its stable.
On average, each OEM's 800 powerplant is making 145+ horsepower. Yamaha competes in this power region too with its 149-hp Genesis 4-stroke engine. …It's a good time to be a high-performance rider!
We took a look at this segment in depth in our 800cc short-track comparison story last issue and further scrutinize it with our 800 crossover comparison
(p. 18) this month. We didn't have independent dyno data from a production sled for last month's issue, but we've got it now!
We put the Polaris 800 Dragon on the dyno at Dynoport for several runs and also received data from the good folks at DynoTech Research. Here's the skinny.
Early optimismWe were optimistic after many late season test rides on the pre-production Dragons. Yet, in our dyno tests we did not exactly see the horsepower numbers we thought we would, but did learn a lot about the engine. Dynoport reported 147.1 hp at 8,000 rpm as the best horsepower after several runs with the Liberty liquid 2-stroke.
While this is lower than the Polaris-stated 154 horses, it's still darn good for an 800cc engine. We also heard that the rings on this engine are particularly hard for longevity and heat protection. Polaris tells us it takes 300-400 miles for break-in and only after that will consumers see the Dragon's peak power.
It also is apparent that this sled responds well to bolt-on mods and 93 octane gas. A quick test by Dynoport, simply adding an SLP pipe to the sled, showed an increase in horsepower to 156. So with a Y-pipe and more, this sled will most likely be a 160+ hp machine.
Rich running sleds have also been a concern for Polaris riders the last several years as many sleds have come from the factory fat and had to have their ECUs re-mapped in order to create peak performance. Several carbureted 600s have needed to change main jet sizes as well.
Another dyno-shop, DynoTech had success in reducing fuel flow from 110 lb./hr. to 95 lb./hr. after adding a Power Commander III fuel-injection module. With the Power Commander, DynoTech saw more than 153 hp, very close to Polaris' stated figure for the Cleanfire Injected machine. It's possible that Dragon owners could use Power Commander III's or BoonDocker control boxes to lean out their own mixture and obtain the magic 154 hp, but they will have to buy and install those separately.
This year, with ever-growing concerns about deteriorating fuel quality, the rich fuel mapping may have been done to provide additional protection to the engine. We would also much rather have a machine that protects itself and has the detonation sensor retard on the engine sooner rather than have a burn down.
Competition dataWe dynoed the 800R powerplant from Ski-Doo at 155 hp at 8,100 rpm, which was impressive. We also dynoed Arctic Cat's 800 EFI at 143.7 hp at 7,700 rpm. Interestingly, the old Polaris 700 Dragon netted 135.8 horsepower at 8,100 rpm and the venerable Cat F7 netted 140.1 hp at 8,000 rpm.
Having looked at these stats again, it seems as though everyone is chasing Ski-Doo's 800R motor as far as pure stock power production. It's important to remember that not every sled that comes off the line makes exactly the same horsepower and it's nearly impossible to re-create the exact same dyno pull every time.
Polaris is on track with its 800 engine and in the light IQ chassis, the Dragon SP will turn more than a few heads on the lakes and trails this winter.
More info:
www.dynoport.com or
www.dynotech.com