Thunder PowerJet

• More Power

• Improved Fuel Efficiency

• Easy Precision Jet Changes

• Adjusts For Altitude and Temperature

• Works on Snowmobiles, Motorcycles, ATV's & other vehicles

The Thunder PowerJet fits any size or brand carburetor.  It is exactly what you need to achieve maximum performance with your engine.  The TPJ improves performance by precise fuel metering with needle valve adjustment.  Fuel distribution is improved by adding fuel through two sources instead of just one.  This means more horsepower at any temperature or altitude.  The TPJ gives you a range of over 10 to 12 jet sizes with precision external adjustment.

TPJ-Single  -  $64.95

 For more information read articles below

     Power Jets have been around for a long time and are a great addition to any carburetor.  Mikuni recognized the benefit of power jets many years ago and still offers their version today.  With Mikuni's version of the power jet, you must unscrew the top of the power jet, reach inside with a screwdriver and start the process of changing jets until you find the correct combination.

     Here is where the Thunder PowerJet is different.  We wanted the Thunder PowerJet to be user friendly so we placed a knurled adjustment knob right out in the open.  Just rotate the knob by hand counter clockwise for increased fuel flow and clockwise for less fuel.  The Thunder PowerJet is nickel plated for corrosion resistance as well as great looks.  The Thunder PowerJet is truly a simple trouble-free product that makes carburetor adjustment easy.
     With the Thunder PowerJet installed, the main jet is decreased by 20% to 25%.  The remaining fuel is supplied by the Thunder PowerJet.  This combination gives you great throttle response due to the smaller main jet's superior atomization.  Throttle response is dramatically increased.  Overall power is also increased for several reasons.  First of all, the Thunder PowerJet can be dialed in so quickly and accurately for any temperature or altitude that you no longer dread rejetting your carbs.  It is about a one to two minute job.  With the Thunder PowerJet, fuel distribution is enhanced because you are now adding fuel in two locations instead of just one.  The last benefit is increased fuel efficiency.  This is due to part throttle riding conditions where you are running on the the smaller main jet.
     The Thunder PowerJet has a huge fuel delivery range from  zero fuel to as much as a #500 Mikuni main jet.  These adjustments can be made in finite increments as small as a 1/4 jet size at a time.  The Thunder PowerJet has enough range to ride from lea level to 15,000 feet as well as any temperature variation.
     The Thunder PowerJet is ideal for stock engines, mod engines, big bores, nitrous, blower or supercharger applications.  Any fuel or additive may be run through the Thunder PowerJet without damage to the seals.
     The Thunder PowerJet can be used with pressurized or non pressurized float bowls.  It can be used on any brand of carburetor.  Each Thunder PowerJet kit comes with everything you need for installation including an excellent installation and tuning manual.  Technical support and information is available at Thunder Products during all normal business hours.
Options:
     The only option available for the Thunder PowerJet is a Deep Well Float Bowl Nut (we recommend it) which will fit on your carburetor eliminating the need to drill and tap your float bowl.  This also places the Thunder PowerJet fuel pickup further from your main jet, eliminating the possibility of fuel cavitation between the two fuel sources.  More information at Deep Well Float Bowl Nuts.  

SnowTech Article

Here's a new twist on an old method; adding a power jet to a carburetor. Remember those? Simple power jets have been used for years as a method of improving the calibration on bigger carbs, like what sleds use. A Power jet consists of a fuel pickup in the bottom of the float bowl, connected through a fuel hose to a spray nozzle that protrudes into the incoming air stream going into the carburetor.  

     How and why is this an advantage? Using a power jet allows you to lean down the main jet circuit with far less fear that the engine will seize on top end, as the power jet supplies the rest of the fuel needed on top end. This has several advantages. Throttle response improves dramatically, and since most riding is done at partial throttle settings, fuel economy is improved as well. Power is improved at any temperature or elevation.   

            What makes the Thunder PowerJet different from a “simple” power jet is that it is adjustable! It has a Viton needle valve (needle and seat) for precision adjustment. It allows for extra fuel to be added to the total fuel delivery, adding to the fuel from the rest of the carb jets. It can be set to the tune of adding zero fuel, all the way to adding as much fuel as a 500 main jet can supply. Think of it as giving you an external adjustment of around 10-12 jet sizes, minimum! A large knurled knob with an index pointer makes adjustment easy (and no more digging into the carburetor). 

The strongest fuel signal is in the 1/2” circle in the center of the carb bore.  The further away you move from the center of the bore, the later the TPJ comes on.  Fuel flow will begin at approximately half throttle delivering progressively more fuel and reaching maximum efficiency in the 3/4 to full throttle range.  The TPJ will improve mid to top end throttle response and protect you from leaning out with extended full throttle runs.

The TPJ is great for piped engines because power comes on at higher than stock rpm’s, so fuel can be easily added in this area without suffering through a rich condition in the lower rpm areas. It also works extremely well on turbo, nitrous and blower applications.

            A one-way check valve is included, so you don’t have to suck the fuel all the way from the float bowl. The TPJ body and all hardware are nickel-plated to resist corrosion, and the viton seals on the adjustable needle and seat are compatible with all fuels, including race gas and alcohol.

Some may wonder how this differs from a Dial-A-Jet. The Thunder PowerJet is not air corrected like a Dial-A-Jet, so there’s no mixing chamber or emulsion mixture. This is raw fuel being delivered here. Thus, the range of adjustability in terms of total fuel delivered is greater.  

Mountain riders can calibrate their sled to work best at any elevation. As they come down the mountain they can add fuel to maintain safe ratios. Or, let’s say you wake up and the temps are colder than your jetting is safe for. No problem, tweak your TPJ and add some more fuel, quickly and easily. The options are many.

Add the Thunder PowerJet to any carbed engine and you instantly gain the benefit of (quick and easy) external adjustability. Then add to it the benefits of having a powerjet. Generally, the bigger the carbs and larger the engine, the greater the performance benefit. Big bore twins are prime candidates (like ones with 38mm, 40mm or honking 44mm Mikuni carbs). Sleds with smaller carbs would still see gains and would also benefit from the external adjustability.