We now offer Dyno tuning with our state of the art Dynojet dynamometer
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Some Q & A regarding dynos, some myths dispelled and a lot of good information.
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How can a dynamometer help you? A dynamometer is a machine that can simulate riding conditions by creating a load on your motorcycle that emulates actual riding conditions. While this load is applied, your machine is stationary on the dynamometer and is connected to a series of high tech analyzers that gather information and convert it to a readable graph. With this information we can see where you are losing power, or not realizing all of your bike's potential. What this means is with this information we can adjust or modify your bike to our geographical location as well as your particular needs. This is especially useful for racing bikes and even casual street riders. We can do jetting changes, fuel injection mapping or any number of evaluations of aftermarket products. A dynamometer is the number one tool used by OEMs and aftermarket companies to evaluate and develop products. There is no better tool for making your bike run at it's full potential or making more power!
How does the Dynamometer work? The word Dynamometer is actually a compound word derived from dynamo and meter. A dynamo is a "power producing" assembly and a meter is a device used to measure units. Therefore a dynamometer is a power producing meter measuring output of engines. A Dynojet motorcycle dynamometer does not measure horse power. It measures acceleration and then calculates torque and from that horsepower. During a dyno run the rear wheel of the motorcycle is placed on a large drum that is very heavy. During the "run" the ability of the motorcycle to accelerate this drum is measured by an optical sensor that records the rpm of the drum. From this the software uses the F=MA formula which, simply stated, says that Force is equal to Mass times Acceleration. Algebraically converted it can know the force as it knows the mass of the drum and the acceleration of that drum from the optical sensor. Once this Force is known it then uses another mathematical formula to find the torque. (t=fdcosine) (translated meaning torque is equal to the force (previously found) times the radius of the drum times the cosine of that angle) Once the torque is known it now uses the HP formula which is HP= t x RPM/5252. Converted this means that the HP is derived from the torque generated at the drum multiplied by the RPM divided by a mathematical constant of 5252. Seems like a lot of work to get to this point but it works! Keep in mind that motorcycle dynamometers measure rear wheel horsepower, not engine horsepower.
A lot of confusion exists regarding HP. Motorcycle manufacturers often advertise engine HP and not rear wheel HP. That is why you sometimes see very high HP figures on the MSO or other OEM publications. We do not have a convenient way to measure engine HP and, realistically, it's not engine HP that we see as there are always losses through the drive train as well as multiplication of torque through the primary and transmission. These modern rear wheel dynos have become the standard in the motorcycle, as well as the automotive, industry.
What will be measured when my bike is on the dyno and how will it be tested? Your bike will be strapped down on the dyno and a pickup will be connected to your ignition system to gather engine RPM data. We will also connect a type K thermocouple to your radiator to monitor engine temperature. We will also be inserting a probe in to the exhaust outlet to monitor the air fuel ratio during the run. The "run" begins by actually getting on the bike and riding it, shifting it through the gears until it gets in to 4th or 5th gear. (this depends on the actual gear ratio, we want to be as close to 1:1 as possible for accuracy) We then push a remote controlled button and snap the throttle open. This is where the sampling begins. Once the engine reaches it's RPM redline the test ends and we then analyze the data that appears on the computer screen. The software converts everything we just did in to an easy to read, formatted graph charting; HP, engine RPM, Torque, MPH and Air Fuel Ratio. With all this pertinent information we can then offer improvements and changes to be made to increase the output of the engine.
How does the air fuel ratio relate to making HP? One of the most important factors in making more and better power is controlling the air fuel ratio. When we measure samples from the exhaust what we are actually measuring is the oxygen content in that exhaust sample. The amount of O2 in the exhaust is relative to the amount of 02 entering the engine. What the 02 analyzer does is compare the amount of oxygen present in the exhaust to the fixed amount of oxygen in the atmosphere (this never changes) When the air fuel ratio is considered rich, there is little O2 available in the exhaust stream and when the air fuel ratio is lean there is available 02 in the exhaust stream.
It is well documented and known that in general terms the optimum air fuel ratio for making the most power is about 12.2:1. Understand that this is not an absolute figure and can change significantly from engine to engine. Understanding that each engine has unique characteristics and flow dynamics adds to the challenge of improving the output. What we do know is that engines that run too lean or too rich will not make optimum HP. Being able to see what the A/F ratio is at each and every RPM along the axis of the graph gives us a wonderful tool for adjusting that A/F ratio.
What is most confusing is that there is a lot of information floating around out there about A/F ratios. Internal combustion, gasoline burning, naturally aspirated engines will conform to this nominal ideal A/F ratio of 12:1. Deviation from this ideal is normal and expected. However, we can find that ideal number by performing runs and "learning" from these runs. The real confusion exists with what people hear and read. Many times the A/F ratio of 14.7:1 is tossed around in discussion and is published quite ubiquitously. This stoichiometric A/F ratio is generally ideal for catalytic converter efficiency and not necessarily for making maximum power. This stoichiometric A/F ratio is necessary on modern, catalyst equipped vehicles for the reduction of Carbon Monoxide, Hydrocarbons and Oxides of Nitrogen but not for maximum HP. What's interesting about this often misunderstood A/F ratio is that it is the same value as atmospheric pressure at sea level but has no relationship to it at all. It's simply a scientific coincidence. What's more interesting is that we find the ideal A/F ratios of modern, properly designed, engines and combustion chambers getting towards the leaner side of the accepted standard. That is, they start creeping up from around 12:1 and make the most power at leaner A/F ratios than older engines. This is a result of good combustion, excellent ignition systems and precise fuel control that allows for better fuel atomization.
Keep in mind that internal combustion engines are not very efficient at converting gasoline from potential energy in to kinetic energy. This is what we are constantly trying to improve when we modify an engine. By allowing us to "look" at the A/F ratio of any particular engine we can customize that A/F ratio in to making the most power for any given engine.
The gas analyzer used on the dyno is a "wide-band" O2 sensor. A wide-band sensor is an 02 sensor that has a working parameter of about 0 to 5 volts. When A/F ratios are very lean they generate a very small voltage at or near zero. When the A/F ratio becomes rich they will generate almost 5 volts. This varying voltage is then sent to the A/D converter on the dyno stack and then converted in to a readable A/F in numerical terms. Narrow band 02 sensors, such as those used on automobiles and some motorcycles in their fuel injection systems, generate a useable voltage of about 0 to 1 volt. These sensors have less sensitivity and their working parameter is not as useful for interpreting A/F ratios.
It is also necessary for 02 sensors to be at or above about 600 degrees F in order to generate reliable voltage readings thus explaining the need for the heater in the sensor. This heater warms the sensor very quickly so that it can be useful as soon as possible. This also explains why modern vehicles have heated 02 sensors. The engine management system needs this information as soon as possible in order to begin controlling A/F ratios and achieve a reduction in tail pipe emissions as soon as possible. Understand that disconnecting 02 sensors reduces or eliminates the ability for your engine management system to operate properly. 02 sensors are as prevalent today as spark plugs and understanding their role in modern engine management systems is vital in achieving contemporary goals of reduced emissions and maximum power.
What do Power Commanders do? Here is where it gets tricky. Power Commander modules are devices that alter the original engine management software instructions. All engine management ECUs are basically a set of instructions that control A/F ratio and ignition timing. On more advanced systems they can control up to dozens of components and controllers. For this discussion we will be limiting it to A/F ratio.
Fuel injected engines are fairly simple in comparison to carbureted engines where the tuner had to have an intimate knowledge (very rare) of how carburetors work, basic physics and a myriad of other incidental factors. This is why most people can never really get the jetting right! The good news is that fuel injection is easier to understand and the computer is doing all the work for you.
Fuel injection uses solenoids that are pulsed on and off (duty cycle or pulse width) to control the A/F ratio. These solenoids can be turned off and on as fast as .001 seconds. Given this incredible speed to adjust is what gives the ECU such fine control of the A/F ratio on a modern vehicle. When the bike is designed the ECU is programmed to pulse the fuel injector of and on and vary that pulse (pulse width modulated) to achieve that perfect A/F ratio. Remember stoichiometric? The ECU determines this pulse and it's width based on several important inputs such as: engine RPM, engine coolant temperature, intake air temperature, exhaust 02 content, throttle position, manifold pressure and others. With all of this information and at any given moment in time the ECU will go to a preprogrammed internal chart (MAP) and look to see what the fuel injector pulse width should be to achieve the perfect A/F ratio for any given situation. This is happening very quickly and hundreds of times per second. What the ECU does to richen the A/F ratio is extend the time that it turns on the fuel injector (pulse width). To lean the A/F ratio it shortens this pulse width. All of this happening up to hundreds of times per second. As soon as some of the input information changes, which it does constantly, the ECU must look up a new pulse width (from the internal MAP) for the new situation and change the A/F ratio to keep up with the new demands. At the same time it is also controlling the ignition timing. It is very busy but easily accomplishes this task with incredible speed.
What are some of the more important inputs that have a lot of influence on mapping? One of the most influential is the engine coolant temperature and I will use this particular input to explain how mapping is done. When an engine is cold it needs a much richer A/F ratio to maintain combustion. This is because the cold engine is not conducive to evaporating fuel so a "little extra" is given to get the job done and eliminate hesitation and stumbling that would occur if it were run at the normally leaner A/F ratio of a warm engine. So as the engine warms up the ECU monitors this and slowly leans the A/F ratio according to a pre programmed MAP in the ECU. This MAP is constantly in use by the ECU to see where the A/F ratio should be at any given temperature.
Imagine a square piece of paper with dozens of boxes laid out on it. Each of these boxes containing a set of instructions on what to do with the fuel injector in each and every case. As the conditions change the ECU is constantly referring to a different cell or box on this sheet of paper or MAP. What a Power Commander does is "get in line" with the output of the ECU and causes the intended signal to deviate in to another ECU which has it's own MAP.
This ECU module (Power Commander) then generates it's own, new, signal to the fuel injector based on it's own internal MAP which is pre programmed or downloaded from the internet. These new MAPS can richen the A/F ratio from the OEMs intended objective in to a newer richer A/F ratio which is better for making HP. The Power Commander also relies on throttle position inputs to help in determining the proper MAP for making power and increasing drivability. Understand that it does not necessarily retain ideal A/F ratios for maintaining reduced tail pipe emissions but will generally increase engine output and in many cases "smooth out" the power curve. Again, it is not an improvement on OEM software so much as it's an improvement in increasing engine output and in some cases smoothing out the power.
On the new dirt bikes that are fuel injected the Power Commander is an absolute "must have" device that, quite literally, replaces the jet kits we have used for decades. With these new high tech race bikes we can now adjust the A/F ratio for optimum power with the Power Commander module. We can measure the A/F ratio at the exhaust, connect a lap top to the Power Commander and down load or create a new MAP for the race bike. Dyno test it, confirm the results and send it to the track ready to go. No more need to carry jets and constantly be changing jetting. The new fuel injected bikes are going to be able to adapt to changes in altitude and temperature unlike anything in the past. It's all good news!
Correction factors, what are they and why so much controversy? Correction factors exist because we all live in different climates and conditions. What if I live at sea level and someone else lives in Colorado at 5000 ft above sea level? How can we compare results that are relative to the conditions we live in? First it must be understood what factors effect engine output and testing.
There are three primary factors that will effect engine output that we can't necessarily control; pressure, temperature and humidity. We'll discuss pressure first. The atmospheric pressure at sea level is 14.7 pounds per square inch. That means that a cubic foot of air at sea level will have a given mass of air under that exact pressure. It also relates to exactly how much oxygen is present in that cubic foot of air at sea level. If I were in Denver, CO, for example, this would not be the same. As we go up in elevation through the atmosphere the pressure is reduced until eventually we exit the atmosphere and there is no pressure and no air (no oxygen either!) So you can easily see that the elevation is very critical to the output of the engine simply because as I go up in altitude I have less oxygen available. This also explains why vehicles lose about 4% HP with every 1000 feet in elevation we rise.
When we start our run the dyno stack reads the barometric pressure and knows the elevation that we are testing at. With this information the software can actually "correct" the readings so that all users throughout the world can compare results without having to figure in the differences in elevation. The good news for us is that we are at about 350 feet above sea level so there is very little correction factor in our runs.
We also need to consider temperature as that has effect on output as well. A colder cubic foot of air is more "tightly packed" or denser than a warmer cubic foot of air. Therefore colder air has more oxygen than warmer air and of course that effects our readings. Most dyno testing is done indoors so the temperature, for the most part, is controlled. Again, temperature is also a factor in the correction process and this information is gathered automatically with our stack. We never go in to the software and attempt to change any of these readings. Temperature readings come directly from out stack and cannot be altered.
Lastly is the humidity of the air. Why does humidity effect output? Simple enough. A cubic foot of air that is saturated with water (very humid) displaces air. Imagine an empty box that someone puts a bunch of marbles in. The more marbles in the box the less room for air. A cubic foot of dry air has more room available for the air and therefore has more oxygen available. Again, the dyno stack constantly monitors this and it is not an adjustable input.
Of the three factors, pressure, temperature and humidity, pressure is by far the most influential followed by temperature and then lastly by humidity. This is clearly evidenced by anyone who has ridden in the high elevation of the western states. As you go up in elevation it is very evident how much power you are losing. The power loses are incredible. By the time you are up around 12,000 feet above sea level, which is easy to do in Colorado you are down 50% in HP!! At the same time if you were riding in 80 degree air and were suddenly thrust in to 20 degree air you would have a difficult time even detecting any differences in HP. And even more so if you were riding in 100 percent humidity, relative or absolute, and then were suddenly riding in the desert at about 5% humidity you would not be able to tell the difference in HP. What this means is that the number one factor to be concerned with is pressure then temperature and then humidity when doing your jetting changes. Do not misunderstand this statement as meaning temperature won't effect A/F ratio because it will. You just can't detect it by "seat of the pants" testing.
Anyone who has raced on the ice knows enough (or should) to make sure to richen the jetting in the winter months otherwise risk engine failure due to overheating the combustion chamber from overly lean A/F ratios due to the more densely packed cold air.
The most important part of this discussion is understanding that fudging correction factors can cause a higher read out but not an actual change. Be informed and always ask what correction factors are used and be sure they are consistent with each run.
There are several "correction factors" that have been developed over the years. The most prevalent one and most often used is the S.A.E. standard. It was developed by the Society of Automotive Engineers decades ago when testing began in earnest during the developmental years of the auto industry. Others do exist but are not as well established or understood. We always use S.A.E. correction factors and never use the others. Why is this important? Well it opens up the door to fraudulent use. If I use S.A.E. on run number one then switch to a more liberal correction factor on run number two I can easily see more HP on the second run simply by changing the correction factor. There are some unscrupulous shops that do this to get a free shot at making more power, or at least an appearance of more power on the graph they produce for their customer.
We offer the most realistic, honest dyno testing that is possible. Although sometimes disappointing in comparison to what we've read or been told the results we get will be real and not contrived. If you are interested in getting the most from your bike and not just snappy print-outs give us a call and set up an appointment and consultation. We look forward to working with you!