ON THE DYNO:

On the dyno, the F7 made 131.7 Chp @ 7500 rpm. The dyno runs were made with the hood closed so the stock cold air intake could be utilized. Because of time constraints, our dyno data did not include fuel flow numbers-- monitoring fuel flow on EFI sleds requires plumbing a custom fuel flow meter inline on dead-head systems or using two fuel flowmeters (one for fuel flow heading for the rail and another subtracting the fuel flow bypassed back to the tank) on recirculating systems. 131.7 Chp seemed low compared to some preproduction units, but it may be in part due to the smaller air inlet snout in the hood.

AT THE TRACK:

During box-stock runs, the F7 pulled hard out of the hole and RPMs stayed constant at an indicated 8100 revs. I believe that the tach was a bit happy (reading too high); as our DynoTechResearch.com full dyno printouts indicate at these typical pipe temps, the F7 showed only 73.5 Chp at 8100, hardly enough to register that 94mph box-stock run if it were, indeed, revving that high.

Dealer prep by the Big Moose guys included adding a D&D clutch kit, D&D airbox breather, and the rear coupling blocks were removed. Out of the hole was a challenge with the combination of better clutching, improved weight transfer, nasty grooves in the racetrack (thanks to a dozen holeshots by a bunch of 200+ HP violent aftermarket "trail" sleds during "halftime"), and the narrow 13" track. On both runs, the sled twisted to one side or another, resulting in half of the track lifting off the now-bare starting line. This resulted in severe track spin, causing the clutches to overshift and bog the motor down to (an indicated) 7500 RPM, then gradually recover to 7900 for the last 1/8^th mile or so. Again, I think this particular sled’s tach was reading high.

ON THE DYNO:

The Polaris 700 made 120.6 Chp at 7800 RPM with an ultra safe BSFC of .72 lb/hphr (pounds of fuel per horsepower per hour). This is 10 Chp less than last year’s Polaris 700, which flowed 10% less fuel than this year’s, even though the new sled has only one size larger stock main jet (450 vs. 440)! This rich(er) condition may be caused by different overall carb specs and new removable airbox.

AT THE TRACK:

The Pro-X hooked up fairly well, and held 8000 RPM for the full ¼ mile on both runs.

White Lake Polaris "prepped" the Pro-X 700 as follows: 390 mains, their own clutch kit (determined by earlier testing on a similar unit), lower windshield and the coupling blocks removed. For both runs, the sled transferred well, and shifted harder pulling the revs down to an indicated 7900 RPM all the way down the track. Note: in order to achieve the high pipe temp that the White Lake guys "tuned" their clutches for, before each run the sled was subjected to lengthy "jackstand burnouts". This may have caused the engine coolant to be high enough to lose HP during the runs since Polaris has a severe ignition timing retard at 80 degree C and above coolant temp.

ON THE DYNO:

The 700 Skidoo made 118.8 Chp at 7600 RPM with a conservative .71 lb/hphr BSFC. With leaner jetting that can be used with 92+ octane gas (mid- .60’s BSFC), you can expect more HP with the power peak sliding up to 77-7800 RPM due to the higher exhaust gas temp.

AT THE TRACK:

The 700 MXZ spun the worst of all the sleds at the shootout. On both runs, the tach read 8000 all the way down the track, indicating severe overrev.

Doug Smith "prepped" the sled by dropping to 480 mains (Jim Czekala called him a "chicken" while he was conservatively rejetting), the center shock spring was stiffened up, and the TRA clutch "clickers" were dropped to reduce engine revs. On my two dealer prep runs, the 700 MXZ still spun, but not as violently as it did in the two box-stock runs. Thanks to the clicker adjustment the tach held 7800 for the full length of both ¼ mile runs.

ON THE DYNO:

The Viper pulled 115.5 Chp at 8400 RPM, with a BSFC of .69 lb/hphr. As our full dyno sheets indicate, the power band is very broad and forgiving for clutch-calibration induced overrev.

AT THE TRACK:

On the track, the Viper bogged excessively (hence the poor "short times"). The bog felt to me like it was caused by clutching rather than carb calibration. Sometimes the stock Yamaha secondary clutches have a hard time returning the belt to the top of the sheaves, often resulting the clutches being partially "shifted out" on takeoff. After the initial bog was overcome, the engine held at 8500 RPM for the remainder of both runs, a slight overrev. But as the DynoTechResearch.com printouts (Jim wanted me to plug that) indicate, the "flatness" of the HP curve, especially beyond the HP peak allowed for good performance even with overrev.

Big Moose Yamaha techs prepped the Viper by installing a Bender clutch kit and adjusting the front limiter strap. As shown by the improved 60’ times, the bog was gone and the engine held 8400-8450 all the way down the track.

ARCTIC CAT ZR900

ON THE DYNO:

On the DynoTech SuperFlow dyno the ZR900 made 141 Cbhp at a stump-pulling 7200 RPM with a BSFC of .71 lb/hphr. Remember, this is warm-pipe data as opposed to that obtained during multi-minute steady state dyno runs. On the first dyno run we had neglected to hook up the TPS, so we missed the typically higher cool-engine pull data. The second and third runs the engine was hotter than normal (for us). Examining our dyno data, it is likely that the warm-pipe ZR900 suffers from the same late exhaust valve opening as the other electrically operated Cat exhaust valve equipped sleds. Note that the HP jumps by 10.3 just as the exhaust valves appear to open at 7200 RPM.

AT THE TRACK:

The ZR900 spun and the tach shot to 7600 RPM and stayed there for both box-stock ¼ mile blasts. I could feel the big twin "flatten out" as the revs climbed to where there was less power, very typical of stock setups.

Big Moose Yamaha/ Arctic Cat techs "prepped" the bone-stock sled as follows: D&D rear helix to pull the revs down, and the coupling blockers were removed. My two "dealer prep" runs were similar—the sled still spun off the line, but the clutch held the revs at 7200 as the skis stayed about 4" off the track for what seemed to be the length of the strip. With ultra-safe, but proper "fine tuning", this resulted in the quickest and fastest machine of the day.

AT THE DYNO:

The Pro-X 800 made a disappointing (but understandable once we examined the fuel flow numbers) 121.7 Chp at 7300 RPM with an 85 octane-safe .75 lb/hphr BSFC. This test was conducted with a 20 degree F air temp! Interestingly, our peak fuel flow on this sled was 102.8 lb/hr which was 10 lb/hr more than last year’s 800 twin. We can say that overall carb calibration, including revised needles, needle jets and airbox contributed to this richness (ultra-safeness). We expect that 390 main jets would cause this year’s 800 to flow the same lb/hr of fuel as last year’s.

AT THE TRACK:

Box stock, as expected, the Pro-X 800 blubbered up to the 330 ft lights, and only then started to clean up. The revs then climbed to 7800, and hung there for the remainder of the ¼ mile track.

For "dealer prep", 400 mains were fitted (I think Jim called the White Lake guys "chicken", too) along with their own clutch setup and chassis adjustments. After more "jackstand burnouts" to get that important pipe temperature up to where they liked it, the sled transferred well, maybe even too well as it felt like it was unloading the track a bit during the holeshot. Downtrack the revs held nicely at 7800, matching the approximate power peak of the hot single pipe. With the 800, it is possible that we exceeded the 80 degree C limit where the ignition will allow full timing (and full HP). Those who are comparing this sleds ET/ MPH should note that during last year’s shootout, the Polaris 800’s wiring harness was fitted with a second coolant temp sensor that was left dangling in the wind.

ON THE DYNO:

The 800 Rev made 132 Chp at 7800 RPM on the best of the two allotted dyno runs with a conservative BSFC of .71 lb/hphr. This is a non- DPM equipped model, and the "break-in" timing retard mode was disabled prior to the dyno certification.

AT THE TRACK:

Box stock, the 800 Rev spun violently and the RPMs held at 8100 all the way, both runs.

During "dealer prep", the Smith Marine guys dropped the mains to still-conservative 380s (for 1500 ft altitude, 20 degrees F) but more importantly added heavier pin weights to pull revs down to where the power is. On both dealer prep runs the sled spun hard out of the holes but Doug Smith’s clutching kept the RPMs at 7800 initially, then creeping up to 7900 at the top end as pipe temp climbed.

ON THE DYNO:

The RX1 made 137.8 Chp at 10,500 RPM, very similar to the first DynoTech test sled. The BSFC was .50 lb/hphr-- deathly lean for a two-stroke but on the safe-side for a highly tuned, high revving four-stroke multi.

AT THE TRACK:

During the two box-stock runs, the RX1 accelerated smoothly out of the hole, held 8800 RPM and slid quickly up to 9600 RPM and stayed there for the remainder of each run. We suspect that, for the average rider, 9600 RPM at full throttle will reduce engine/ valve train wear and increase longevity without a great reduction in performance. Four-stroke engines’ power peaks are unaffected by pipe temp, and we can expect more acceleration by getting the clutches to shift closer to 10,500, but that improvement wouldn’t be as dramatic as a 900 RPM shift on a two-stroke. Comparing the dyno numbers, we can see that the RX1 has a flat, most forgiving powerband.

For dealer prep, Big Moose techs added a Bender clutch kit only. During the two dealer prep runs, the sled pulled much harder out of the hole, and the revs climbed quickly to 10,200 and laid there for the duration. One other attribute of the four-stroke is that while two-stroke power fades quickly with increased coolant temp (reduced volumetric efficiency) the four-strokes’ power seems to thrive as coolant temp goes up. This is probably due to the oil "thinning out", with less friction very much like what happens when NHRA Pro Stock dragracers and NASCAR qualifying cars run ZERO weight oil.

I should note that this sled was exceptionally quiet during my runs--this was confirmed by Jim Czekala. While monitoring stock sled decibels during each acceleration run (to compare with aftermarket sleds’ dB to award the DynoTechResearch.com Quiet Giant awards), Jim found that, during full throttle acceleration, the RX1 was by a large margin the quietest of all sleds- including the 600s.