Our first glimpse of Polaris' new 800 XCR came at Canterbury Park near Minneapolis, Minnesota, last January. At the unveiling, Polaris Snowmobile General Manager Bob Nygaard boasted that this new machine was significantly
stronger at both the top end and the midrange. We listened, but reserved judgment until we could see for ourselves at our spring test session, and hopefully on a dyno. Afterall, it ain't braggin' if it's doin' and this brand new motor showed us it's definitely doin'!
As usual, our resourceful dyno guys commandeered an early release of the hot new 794cc Fuji mill as we requested. Based on what we've seen on the dyno, we can truthfully say that this is the strongest production 800 motor ever!
The new motor uses RAVE-like variable exhaust valves, actuated by pressure in the cylinders to smooth out the acceleration curve and gain another four to six horsepower in the midrange. What makes the Polaris Variable Exhaust System different is that the guillotine valve opens and closes the subports on either side of the main exhaust port, where Rotax's design only modifies the main center port. "The fact that Polaris' design handles all the port openings instead of only one definitely helps it make its power," explained Dynoport's Rich Daly.
The powerband is extremely generous on this new motor. Tuners have a 400 rpm spread to hit for more than 155 horsepower. Our test sled hit its peak at 159.2 ponies at 8600 rpm. "We wanted to get it to hit 160," said Daly. "We hit peak power on the third pull. The pipes definitely like to be heated up, but not over-heated."
One of the many new features on the XCR is a temperature sensor which automatically retards the timing if the water sensor exceeds 160 to 170
degrees Fahrenheit. The sensor is also throttle-position sensitive, so at trail speeds, it allows for slightly hotter running temperatures before it begins its fail-safe mode. If the water gets significantly hotter once the timing has been modified, it will begin a controlled misfire.
Other engine safety features of the new mill include an overrev limiter, which will not allow the motor to run at unhealthy speeds. There is also a Low Octane/ Premium fuel switch onboard the sled. This allows owners to make a slight timing change based on the quality of the fuel available. "We played with the fuel switch a little," reported Daly. "We found it richened up the motor by about one or two main jets. That's a nice feature for guys who ride in rural areas where gas quality can be sketchy. The richening didn't affect performance enough to be noticed from the seat."
Daly estimated that there is definitely some room for aftermarket shops to massage more power out of the new motor. "You can expect to see about 10 more horses from a set of pipes. Silencers can add three to four more. It should be responsive to porting, too, since it has such a broad powerband."
Polaris is finally offering a competitive sled in the 800 class. It has the power and torque throughout the operating range to satisfy both lake runners and trail riders.
1999 Polaris Indy 800 XCR
Air Density: 98.0
Fuel: 94 Octane Pump Gas
| RPM | CBT | CBHP | BSFC | FUEL | H2O |
| 5600 | 65.0 | 69.3 | .84 | 57.3 | 99.0 |
| 5700 | 65.3 | 70.8 | .80 | 56.3 | 99.5 |
| 5800 | 65.6 | 72.4 | .79 | 56.8 | 99.5 |
| 5900 | 66.8 | 75.0 | . 77 | 57.0 | 99.5 |
| 6000 | 68.0 | 77.6 | .75 | 57.6 | 99.5 |
| 6100 | 68.3 | 79.4 | .74 | 58.4 | 100.0 |
| 6200 | 68.8 | 81.2 | .75 | 59.9 | 100.0 |
| 6300 | 68.9 | 82.7 | .76 | 61.8 | 100.0 |
6400 | 70.4 | 85.8 | .76 | 64.3 | 100.5 |
| 6500 | 73.7 | 91.2 | .75 | 67.5 | 100.5 |
| 6600 | 76.5 | 96.2 | .75 | 71.0 | 100.5 |
| 6700 | 79.4 | 101.3 | .74 | 74.1 | 100.5 |
| 6800 | 83.1 | 107.6 | .71 | 75.8 | 100.5 |
| 6900 | 83.8 | 110.1 | .72 | 78.7 | 100.5 |
| 7000 | 87.1 | 116.0 | .70 | 80.1 | 100.5 |
| 7100 | 87.4 | 118.2 | .70 | 82.3 | 100.5 |
| 7200 | 89.6 | 122.8 | .68 | 83.1 | 100.5 |
| 7300 | 89.7 | 124.7 | .68 | 83.5 | 100.5 |
| 7400 | 90.3 | 127.2 | .67 | 84.7 | 101.0 |
| 7500 | 90.1 | 128.7 | .68 | 86.0 | 101.0 |
| 7600 | 90.0 | 130.2 | .68 | 88.1 | 101.5 |
| 7700 | 90.3 | 132.4 | .69 | 90.7 | 101.5 |
| 7800 | 90.8 | 134.8 | .69 | 91.6 | 102.0 |
| 7900 | 91.4 | 137.4 | .68 | 92.0 | 101.5 |
| 8000 | 92.3 | 140.6 | .67 | 93.1 | 102.0 |
| 8100 | 94.3 | 145.5 | .66 | 94.8 | 102.5 |
| 8200 | 95.0 | 148.3 | .65 | 95.8 | 103.0 |
| 8300 | 96.9 | 153.1 | .63 | 95.2 | 103.0 |
| 8400 | 97.4 | 155.8 | .62 | 95.7 | 103.5 |
| 8500 | 98.2 | 158.9 | .63 | 99.2 | 103.5 |
| 8600 | 97.2 | 159.2 | .64 | 100.6 | 103.5 |
| 8700 | 95.0 | 157.3 | .64 | 99.5 | 104.0 |
| 8800 | 92.4 | 154.8 | .65 | 99.2 | 104.5 |
| 8900 | 89.4 | 151.5 | .68 | 101.9 | 104.5 |
| 9000 | 86.0 | 147.3 | .71 | 103.4 | 105.0 |
| 9098 | 81.8 | 141.7 | .75 | 104.8 | 105.0 |
RPM: Engine crankshaft speed.
CBT: Corrected Brake Torque.
CBHP: Corrected Brake Horsepower.
BSFC: Brake Specific Fuel Consumption.
FUEL: Actual fuel flow pounds per hour.
H2O: Water temperature in degrees F.