You may have questions about how the MPI turbo kit works at different elevations; or may just be wondering why MPI over the competitors?
We sat down with the guys at Snow Tech Magazine this past fall to discuss the details on the MPI turbo kit. – Below is the article published in the December 2017 issue; article is re- published with permission of Snow Tech Magazine.
Mountain Performance (MPI) 850 Turbo Kit
“After reaching a business agreement this past spring, together Straightline Performance and Mountain Performance (MPI) have been busy developing a low elevation pump gas turbo for the Ski-Doo 850 E-tec. Some may recognize the MPI name as they were the first to produce an 850 Ski-Doo turbo kit which has been on the market for over a year now with great success at high elevation. The first step in the MPI/Straightline plan was to ultimately produce a premier low elevation turbo kit for the high-performance enthusiast. This not only gives the trail rider the fastest trail sled, but the mountain rider also has the availability to ride at both low and high elevations with very minimal changes and consistent HP the entire time.
You may be asking why do I need a turbo on my 850? It’s already screaming fast. The phrase, and meaning behind a turbo is to essentially “bring your own atmosphere.”
As we all know conditions change from day to day. In turn one day your sled may run great, another it may run mediocre. Atmospheric air pressure changes, along with temperature and humidity are the factors in horsepower and performance of any engine. The “basic” concept behind an electronic boost controller is to measure and recognize current atmospheric pressures to ensure that the “total” boost level remains constant, no matter what conditions exist.
For example; one perfect atmosphere is 14.7 PSI, but normal atmospheric pressure typically ranges from 10 – 14.3 PSI depending on elevation, and atmospheric conditions (temperature, pressure, and humidity).
Here is quick couple of examples to help explain “total” atmospheric pressure
#1. Theoretically; if we are trying to achieve 18.6 PSI total pressure for optimal performance with the stock machine using pump gas, and the current atmospheric pressure is 14.2 PSI the boost controller will recognize that it needs to make 4.4 PSI in boost, to produce the total 18.6 required.
#2 If Current atmospheric pressure is 10.6 PSI the boost controller will recognize that it needs to make 8 PSI of boost to achieve the same 18.6 PSI that is established above as optimal performance.
This is why when people ask, “how much boost do you run?” it’s nearly impossible to state a specific boost pressure without understanding that there are too many factors to answer this question.
A self-compensating turbo charger system (a turbo system that makes its own adjustments based upon atmospheric pressure) eliminates the atmospheric pressure variable on any naturally aspirated engine. Thus the power loss that is often noticeable on any naturally aspirated engine is no longer a factor with a boosted engine. This creates the consistent, constant, and guaranteed power all the time.
At a consistent 200HP, a minimum of 35HP- 50HP over stock depending on the day, the MPI kit is the most powerful modification available for your 850 while still maintaining the reliability of the stock machine. Electronic Altitude Boost Control (EABC) and Automatic Fuel Tuning make this “Hands-off Safe”. The kit’s precise recognition of correct atmospheric conditions, create the consistent boost levels required while changing the required fueling through its additional injectors. It’s no secret that the 850 Ski-Doo engines are engineered with advanced technology. This allows for increased HP without sacrificing the longevity of stock components. Straightline’s in house dyno facility has also confirmed it with over 230 dyno pulls at 200HP on one motor alone with normal signs of wear.
Not only has the Straightline/MPI 850 been proven on the dyno for 100’s of pulls, but In-field testing on the asphalt has also confirmed that the turbo Ski-Doo 850 is capable of running passes similar to the 250-300hp kits on the Yamaha and Arctic Cat production turbo sleds. This is the same kit you can purchase for your sled; this sled is all stock except for the low elevation turbo and clutching. During its first day’s out the MPI turbo kit ran 5.7 in 660ft at 116 MPH. In comparison, a stock base line 850 runs 100MPH in 660ft. The MPI Turbo kit includes the following features.
- 200HP at all altitudes/Conditions – includes EABC (Electronic Altitude Boost Control).
- The Entire Turbocharger Module comes pre-assembled — Just unbolt the OEM muffler and install the complete turbo/muffler assembly (use all OEM mounting).
- Aluminum Airbox with advanced air box design provides the superior throttle response compared to a non-air box system.
- Billet Manifold houses 2 additional 35# injectors.
- The Entire Turbo Assembly is Stainless Steel. Including the High Flow Stock Sounding Muffler or the optional Lightweight Mountain Muffler.
- Uses Proven MTA / Billet GT2860RS Oil-less Turbocharger. Ceramic Ball Bearing and Billet Aluminum Turbo CHRA – Better cooling and saves weight.
- Bolt-on installation in hours, not days. No fabrication required, all parts included.
- “Sea-Level Safe” Premium Pump Gas. Automatic Fuel Turning and Automatic Boost Control makes this “Hands-off Safe”
To make the low elevation turbo kit 100% turn key Straightline Performance also offers an adjustable clutch kit specifically designed for the turbo kit.
For those of you who are looking for even more performance there are also Lake racer/ full race HP variations & upgrades available from 250-300 HP!”