SNOWTECH PRODUCT EVALUATION
Land & Sea DYNOmite Engine Dynamometer
One of the more interesting devices we have here in the SnowTech shop is an engine dyno, the Land & Sea
DYNOmite. The prospect of being able to independently verify power output is very attractive. How much horsepower does the new engine from brand X make? What kind of power gain will I really see from this set of pipes? What RPM does this combination make the most power at? The possibilities are endless.
The basic DYNOmite package that sells for $4495 consists of the dyno itself, a hand held computer & cable, a manual load valve, water hoses, and hardware needed to attach and remove the dyno from the engine. What you need is a sled to be tested, a clutch puller to remove the primary clutch, and here¹s the catch; an adequate water supply.
The whole process is actually quite simple. You remove both clutches and place the dyno onto the crankshaft with the torque arm on the jackshaft. Attach the load valve and the water supply and return hoses, and attach wiring to monitor engine RPM. Once the engine is warmed up, you apply throttle and control the load valve to stabilize the engine at some RPM. Once stabilized, you increase the load and sweep the engine RPM while the computer captures the torque readings. The whole data capture is done in about ten seconds. That¹s it.
How The DYNOmite Works
As you probably already know, Horsepower = RPM x Torque / 5,252. The DYNOmite (like most dynamometers) provides both a way to load an engine (via its compact water absorption brake) while monitoring RPMs (with its digital tachometer) and Torque (with its electronic strain gauge). The DYNOmite computer collects the data at up to 200 readings per second, then filters and displays the data in usable horsepower vs. RPM format.
The DYNOmite's water absorption brake receives water (via the garden hose fed load control valve assembly) which it pumps through its specially designed recirculating vanes. Engine horsepower (which is normally absorbed overcoming the drag of running the vehicle forward) is instead absorbed as heat generated pumping the water around INSIDE the brake!
The force created by the internal impeller's pumping water against the stator (external housing) vanes tries to rotate the brake assembly. An aluminum torque arm resists this rotation. The DYNOmite uses an integral strain gauge to electronically convert the bending action that this force creates in the torque arm to a digital foot-pound display.
The computer then takes all the operating data, performs the calculations, and displays it in a variety of optional formats. Filtering and averaging smoothes the data into honest SUSTAINABLE power figures.
WATER SUPPLY REQUIREMENTS
The DYNOmite¹s water brake loading capacity is a function of its ability to convert an engine's power output into heat. Some engine dynamometers use huge electric generators to load the engine; the electrical output is then absorbed in heating a resistor array. Similarly, the DYNOmite (like other water brake dynos) loads the engine via a specially engineered low efficiency water pump. The engine's power is still absorbed in the pumping process as waste heat.
To avoid damaging cavitation boiling inside the water brake, it is mandatory that adequate water volume and pressure be available at the load valve, and adequate discharge lines installed for the power being absorbed. This is where we ran into trouble; having a consistent supply of water, without fluctuating pressure. Our solution? Land & Sea offers a small gas-powered (Homelite) pump, powered by a two-stroke engine. This was perhaps the single most important thing we did. Now we have a contained water system, using a twenty gallon container (Land & Sea tells us we can use a five gallon bucket) that holds the water (mixed with automotive anti-freeze for cold weather testing).
How accurate is the DYNOmite? At first, we questioned the repeatability of the dyno. We have learned that it is unfair to compare a $4495 dyno against a Superflow that costs $50,000 or $100,000. Our best comparison was to our Dynojet SLEDyno that measures track horsepower by measuring the amount of time it takes to rotate a heavy steel drum, selling for a similar dollar amount.
It was actually our experience and knowledge from using our track dyno that allowed us to really figure out the DYNOmite. We¹d heard stories about shops that had a DYNOmite but were never really able to figure it out, or just simply couldn¹t get it to do what they wanted. We were in that boat for a while too. Getting the water supply bit figured out was the first step. As with any technical instruments like this, there is a learning curve, and it takes a level of commitment to sort through the variables and procedures. We found the Land & Sea technical reps to be very helpful with our questions, leading us down the path of proper testing procedures.
The next missing link was the accuracy of the SLEDyno weather station; we could use our temperature, humidity, and ABSOLUTE barometric pressure readings from our SLEDyno hardware and enter them into our DYNOmite computer. This provided the level of accuracy (and repeatability) to our corrected horsepower readings that we never had before. Once we discovered how important this was for repeatability and reliable testing, we immediately upgraded our DYNOmite with the Land & Sea Weather Station that automates the whole process. The Weather Station is a little black box that instantly enters the weather variables into the DYNOmite computer at the exact moment you press the ³test² button and begin your dyno test, and your results are automatically corrected.
Being able to print out fancy graphs was important to us, as was the ability to print out runs with the RPM, torque and horsepower in a neat printout just like we format all of our dyno tests. This required us to upgrade to the Dyno-Max software. As you can tell, the results are impressive. The capabilities of this software are staggering, even intimidating, but this was another critical step in making our dyno system do what we wanted it to.
The next step was to automate the test sequence. Having to hold the throttle with one hand, press the ³test² button with another, and control the load valve with another made for a three-handed job. The solution here was to upgrade to the Electronic Servo Load Valve. Now all we do is enter the desired ³Holding RPM² into the computer (which is the start-RPM for our sweep test), and enter an ³End RPM² for the end of the test. Start the sled, warm up the engine, apply throttle, let the servo stabilize the engine RPM, hold it to allow the pipe temperature to stabilize, press ³test², and the computer controls the RPM sweep test based on the parameters you¹ve entered. From the time you press ³test² to the end of the run is about 10-15 seconds.
All said and done, we can now recommend the basic DYNOmite system, water pump, Dyno-Max software, Auto Servo Valve, a full-function cable (allows connection of weather station, automatic servo valve and Dyno-max software and future upgrades), Weather Station, and an RPM pickup that allows us to track engine RPM on the dyno instead of using a pick-up on the ignition system. The DYNOmite RPM pick-up is more consistent and doesn¹t have any data ³drop-out² like what can happen with ignition pick-ups. The full-function cable allows the addition of fuel-flow tracking (BSFC), exhaust gas temperatures, water temperatures, and a host of other variables to fully expand your system into whatever you want it to be. The possibilities are near endless.
There is so much more to understanding and performing accurate dyno tests that it can¹t possibly be covered in one short product review. In reality, it has taken us several years to get to this level of proficiency, but then again we¹re magazine editors seeking the truth. Suffice it to say that we have found the DYNOmite to be a valuable tool that can provide the information many shops and dealerships so desperately need, at a cost much lower than other dyno equipment. Whether it will fulfill your individual shop¹s needs is something that you will have to determine, but you don¹t have to rely solely on information provided by others; you can find the truth yourself. Contact Land & Sea at 603-329-5645, or visit www.dynomitedynamometer.com for more information.