Frequently Asked Questions

Why does HM Turbos use a Cold Air Intake on your kit?

HM Turbos also uses a cold-air intake, one of the few companies to offer cold air intake on turbo kits. Remember that cold air is more dense, that is, it carries more oxygen than hot air. For every 10 degrees F. you lower your intake temperature, your engine produces 1% more horsepower. An example: one turbo kit breathes hot air under the engine compartment versus another turbo kit which uses a cold air intake and makes the temperature difference 100 degrees F. The turbo with the cold air intake kit has a 10% advantage over other turbo kits. More oxygen means more horsepower-- remember cold air carries more oxygen!

What is the maximum boost capacity these kits run?

Anything above 15 lbs. of boost, including spikes will damage the pressure transducer in the fuel management control box. At 15 lbs. of boost, the fuel pump is at maximum capacity. If boost exceeds this level, an aftermarket EXTERNAL fuel pump as well as a custom fuel management controller is required. Both of these can be purchased through HM Turbos, call for details.

Is there still be a break-in period of time?

Yes, all new engines require a break-in. Normally aspirated (stock) engines require a one tank of fuel break-in period. HM Turbos recommends two tanks of fuel for a break-in period of time. This allows for the pistons to take set to the clearance. Most piston seizures result from too much heat being induced into the piston. Pistons expand when heated; if heated too much they will grow larger than the cylinder and piston seizure will result. Long pulls up a steep mountain will result in stressing the pistons. If you are jetted a little on the lean side, you will be a major candidate for a new piston and cylinder. The two tank break-in also allows you plenty of time to dial in your jetting and get used to the awesome power of this kit.

Will running a turbo wear my engine out prematurely?

Yes, it is impossible to make more horsepower and not experience added wear to your engine. The most important thing that you can do is to make sure you are jetted correctly. Running your engine on the ragged edge can promote detonation even if you use 110 octane fuel. Your Polaris Dragon has a detonation sensor. If detonation occurs, you must add more fuel! Just because your engine has some safeguards, don't depend on the detonation sensor to save your engine watch your jetting! Running quality fuel with enough detonation and the recommended oil will save you in the long run.

Why do you use an AIR TO WATER Inter-cooler on your kit?

When air is compressed it generates heat. Most turbo chargers fall into the 70 % efficiency range. At boost levels in the 10 psi range at 6000 ft you can expect to see charge temps in the 250 degree range. That is why we run the air to water intercooler, it allows for full cooling at any speed, including deep snow conditions in the trees at slow speeds. The intercooler takes over 120+ degrees out of the charge temperature with less than 1 psi of pressure loss. This equates up to a 15 % horsepower gain over non- Air to Water inter-cooled kits and extends the life of the engine components. It also helps to prevent detonation and allows you to run less boost and make more horsepower. Less boost requires less octane in the tank, saving you money.

Remember, 1 lb. of boost equates to approx 10 hp. By using a air to water intercooler, you are essentially gaining 2.5 lbs. (25 hp) over other kits running the same boost level without air to water intercooling.

How can the Turbo become damaged?

  • The most common way a turbo can be damaged is when catastrophic engine failure exists. A hard piston seizure can damage a turbo if metal particles are sent down the exhaust pipe into the turbo.
  • Second, over-speeding your turbo can damage it. Over-speeding can occur if you turn your boost up too high. The series 66 maximum safe turbo boost limits are as follows:

BELOW 8000 ft elevation;

  • 700cc engine can run up to 16 lbs of boost
  • 800 cc engine can run up to 14 lbs of boost

Call for detailed compressor mapping if running higher boost numbers or higher elevation

  • The third way is through debris entering the intake. Ice, windshield darts, foreign debris will damage the intake compressor.


  • The fourth way the turbo can be damage it by to much restriction on the air inlet side of the turbo. Depending on boost levels and snow conditions , HM Turbos recommends as much intake surface area as possible. Install vents!


  • The fith way is by disassembling it. Many turbos have been damaged by customers disassembling it out of curiosity and then reassembling the turbo. Anytime the turbo is disassembled, there is a special procedure and adjustments that MUST be performed by a trained turbo technician.

DO NOT experiment unless you are willing to pay the consequences.

What kind of horsepower can your kit develop?

The 800 Dragon and the 800 Pro RMK with the HM Turbos turbo kit develops 243 hp @10 psi of boost at sea level or 209 hp @ 8000 ft with 10 lbs of boost. Power levels will be higher with more boost with potential of up to 300 hp. Most riders prefer 8-10 lbs of boost, with extreme mountain riders at 10-12 lbs of boost. Drag racers 12-14 psi of boost. All of HM Turbos turbo kits can be used with pump gas or race fuel. The kits produce 200 hp on pump gas and up to 300 hp on race fuel.

What kind of turbo is used?

HM Turbos uses the Aerocharger II turbo series 66. this is the only self-contained turbo in the world that uses a " variable area turbine nozzle" (VATN). The vanes of the VATN have the ability to pivot, which directs the gas velocity as it enters the turbine. The benefit of this is that it acts like a small A/R when asked to and a large A/R when required. In other words the VATN becomes its own boost control without the use of a waste gate. Because it has no waste gate, all the exhaust gas energy is available to spin the compressor wheel and therefore there is no "waste". Another benefit of the turbo is that the turbine speed is always controlled by the VATN. This allows for the largest possible A/R for the boost pressure at that instant. This situation will keep exhaust gas back pressure to be less than the boost pressure. This characteristic is not generally feasible with conventional turbos without the turbines being so large that it becomes unridable and unresponsive at low speed. This situation is called "turbo lag"; a very undesirable characteristic of most turbos.
To sum it up, this turbo provides:

  1. A variable Area Turbine Nozzle for quick response, which virtually eliminates turbo lag.
  2. A self- contained lubrication that requires no oil tank or coolant lines, thus increasing reliability and easier installation.
  3. A ball bearing design for quicker turbo spool up for faster acceleration.
  4. The complete turbo weighs 16.84 lbs (66 series), one of the lightest turbos used by any aftermarket snowmobile company. 


When coupled with no oil tank, no oil pump, no coolant lines, no waste gate, no blow-off valve; this turbo package allows for a high power to weight ratio.

Contact Us

HM Turbos
7105 Hwy 12 W
Lolo, MT  59847

Phone: +1.406.273.6111

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