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The
Harley-Davidson ® High - Performance Cylinder Head Design and Engine
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Complete Engine Rebuilds - Fuel Injection and Carburetor Tuning - Chassis Work - Parts - and More ... Very competitive pricing |
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HOW TO READ A DYNO GRAPH First of all, if you are new to the automotive world you may be asking yourself what a dyno graph is. Well, a dyno graph is a graph that displays the torque (in ft lbs) and horsepower (HP) that an engine makes over the engine's RPM range (rotations per minute). Now your next question may be what is torque and what is horse power? Okay now stick with me on this. Torque is the force (measured in pounds) it takes to cover a distance measured in feet (torque = lbs x ft) and HP is whatever the torque value equals divided by the amount of time it takes to reach that distance. (HP = torque(ft lbs)/ time (s)). I find it easier to understand in practical terms. Say you have a 20 lb box and you want to lift it 3 ft off the ground. In order to lift 20 lbs you need to apply 20 lbs of force. Therefore the torque is equal to the 20lbs of force multiplied by the 3 feet it traveled equaling 60 ft lbs. Now, HP is equal to the 60 ft lbs of torque divided by the (lets say) 5 seconds it takes to move it 3 ft, the HP then equals 12. So this individual makes 60 ft lbs of torque and 12 HP while lifting a 20 lb box 3 feet up in 5 seconds time. This is how the engine works. An engine can be designed to produce more torque creating a quicker acceleration from the throttle and more HP can be produced to get to the destination quicker. That is when Johnson Engine Technology™ comes in best! It is important to have the proper balance or else the amount of HP you have means nothing. |
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Knowing this, let me explain to you how to read the dyno graph to the left: Torque is represented on the right of each dyno graph and HP is represented on the left. Both of these values are represented on the graph by the same color shade as that of the font of the bike in question (found in the upper left corner). For example, to the left is a dyno graph comparing the HP and torque of two different bikes. One is a stock EVO which will be represented in shades of blue, and the other is a J.E.T. EV-27 combination (once an EVO stock bike) which is represented in shades of red. (The name "Carlson" is the last name of the individual that owns the bike Johnson Engine Technology worked on and dynoed.) |
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Now torque is shown to be displayed on the graph with the colors pink and light blue (as indicated by the small color blocks). The pink block corresponds to the pink line on the graph representing the J.E.T.EV-27 combo because it is a shade of red (96 ft lbs torque); and the light blue block corresponds to the light blue line on the graph representing the torque value of the stock EVO bike because it is a shade of blue (75 ft lbs torque). The same happens with the HP found on the left of the graph. The color blocks indicate HP to be displayed on the graph with blue and red lines. The red line then shows the HP value of the J.E.T. EV-27 combination (84 HP) which is compared to the blue line displaying the HP value of the stock EVO (only 58 HP). It is evident here by the graph alone that a bike with the J.E.T. EV-27 combination performance package by Johnson Engine Technology makes 26 more HP and 21 more ft lbs of torque than the 96 Heritage Stock EVO bike. So what do you think...need some modifications?
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