AmSnow.com is now SnoWest.com
Next Stages
Under hard launches on the high horsepower programs, if you have a half tank of fuel or less, some machines experience a lean bog due to momentary full starvation with the stock fuel pump. One Stop Performance (onestopperformance.com) makes a surge tank that you can install in the stock fuel tank. The OSP unit consists of a higher volume fuel pump that continuously feeds a small aluminum tank that resides inside the stock tank. This ensures you having more fuel than you will need, especially under hard launches. This sled only exhibited this issue under hard launches on Power Trail, and with less than 5 gallons of fuel. The OSP product worked great and was easy to install and well constructed.
Another popular performance enhancement is an adjustable wastegate. A wastegate in a turbo controls partial and maximum boost settings by bleeding excess exhaust volume that spins the turbine inside the turbo. The stock wastegate starts opening at 4 psi of boost and doesn’t allow for adjustability. Since we were already ordering the surge tank, OSP sells a billet adjustable wastegate that allows for precise adjustability and the turbo to spool up quicker. TD makes a tune designed to work with the wastegate, so we added that too. The OSP wastegate spools the turbo up quicker, and in side by side testing, the wastegate is worth about 2 sled lengths right on holeshot. OSP also makes a host of products which we’ll review in another article including braces to reinforce the engine and jackshaft on ProCross sleds.
The last stage of tuning was to try clutch setups. The stock clutches on the Procross sleds run hot, especially on the turbo sled, so we wanted to reduce heat. One way to improve performance and reduce heat is to run different clutches. We decided to start with a different secondary, STM’s 11.0-inch Tuner Secondary. This larger diameter clutch is beautifully machined billet and uses old style Arctic Cat secondary helixes and a traditional torsional spring. This allows for a wide range of helix angles and spring options. Also, due to the larger diameter of the clutch, you effectively gain lower initial gearing and can run a more aggressive helix with a quicker upshift. We had limited time to test prior to the publishing deadline, but in initial testing we were able to improve acceleration across the entire range and it provided a smoother backshift. Even more importantly, the clutch dramatically lowered the clutch temperatures. We will also be testing one of STM’s Rage IV primary clutches as a next tuning step.