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The most appropriate dynos (considering cost and ...
Some shops run their engines on test stands, like...
The SpinTron by Trend Performance can examine the...
Dyno Decisions Depend on Business Model
Making the decision to add a dyno to your operation is a big one. A dyno can be a huge asset or an ugly drain on your resources.
By Len Emanuelson
If you need a dyno only three or four times a year, you’re probably better off renting dyno time from another facility. If you build race engines for a living, an engine dyno is an essential part of how you do your job and ultimately the value you provide to your customer.
So what are the pressing reasons to own a dyno? In engine building terms, knowledge is horsepower, and without a dyno your base of knowledge is very limited. You don’t know much of anything for sure about the engine you are ready to ship. You have theories, and you may have history with a certain engine combination, but as an engine builder you don’t know what that particular engine does until you put it on the “pump.”
If you simply want to check that everything is okay before you send an engine out the door, a run test stand is a more economical and time efficient. You can check oil pressure, manifold vacuum, set dynamic ignition timing and adjust the carburetor. All of these adjustments are a huge added value to your customer and prevent costly comebacks due to unforeseen things like oil and vacuum leaks.
However, if you are serving high end performance customers and especially racers, you need to know more, like does the power curve match the application; does the brake specific fuel consumption (BSFC) validate the efficiency of the engine combination, and does it meet the fuel consumption goals. NASCAR and endurance engine builders spend countless hours working on reducing fuel consumption while keeping power up. In the ultra competitive nature of racing today, a couple of horsepower can mean the difference between winning and losing. A super accurate and repeatable dyno is the only way you can ensure success.
Over the past 40 years I’ve had the privilege of watching this nation’s top engine builders dyno test engines. The dynos have ranged from state-of-the-art computerized dyno cells to an ancient Go Power pump hooked to a garden hose and operated with a hardware store gate valve. In fact, many of the dyno setups I’ve seen used by some of the best engine builders are hybrids, with a power absorber from one source, and the data acquisition from another.
What I have taken away from this experience is that there is no standard “must have” setup that will serve the needs of everyone. Engine builders have individual needs and usually end up innovating and adapting a dyno system to fit those needs. You may need a dyno that can take stable load readings from 1,500 rpm. Or in the case of engine builders like Kenny Duttweiler you need a dyno that can handle upwards of 3,000 hp at 8,000 rpm very different requirements that require very different dynos.
Once you make the decision to take the leap, the most important thing you can do is step back and thoroughly research which dyno is right for you. The two main categories of dynos, (engine and chassis), serve very different needs. If you are an engine builder you probably need an engine dyno. If you are a repair/tuner shop you most likely need a chassis dyno. It all depends if the bulk of your work is with the engine in, or out of the vehicle. The ideal situation is to have both.
First, with an engine dyno you are able to quantify the engine without any outside influences. When you put the engine in the car and roll it up on a chassis dyno, you get a more accurate picture of what you have. How is the vehicle’s exhaust system, air inlet system, accessory drag and driveline affecting power output? Gremlins like low charging system voltage show up right away and are easier to troubleshoot on the dyno than by checking lap times at the track. Ultimately, the final test is on the track with data acquisition and data logging. Comparing the data from all three tests can be a powerful tool to making you and customer winners.
Some of the things you should know about dynos if you are considering adding a dyno to your operation for the first time are:
Do you have the space a typical engine dyno has a footprint of 20’ x 20’, and you need a place for a 1,500 gallon water tank to supply a large capacity water brake absorber dyno.
Can your immediate shop area and your neighbors handle the noise? And equally as important, are you zoned properly?
Costs purchasing a dyno is just the start. Building a cell, wiring it, plumbing it, building an exhaust and air inlet system all run the cost up.
Dynos need maintenance like any other tool or piece of equipment, dynos need fixing and upgrading on a regular basis.
Do you or one of your employees have the expertise to operate and troubleshoot a dyno?
The primary types of engine dynos are water brake, eddy current, and AC/DC motor/drivers. A water brake is the best choice for most engine shops. They have the torque capacities reaching 2,000 ft.lbs. and more. And most have a 10,000 11,000 rpm rev limit that will cover most conventional engines.
Eddy current dynos while more precise and faster reacting, typically have lower power and rpm ratings and are more expensive. Eddy-current absorbers offer quicker response so they better handle transient load changes. In contrast, large-volume water-brake absorbers require close to a second to fill or drain and even the best (lower volume) still take fractions of a second. An engine builder’s dream dyno would be an AC motor dyno that can simulate a lap around a racetrack or roadcourse, but with the price tag bouncing off $1 million, don’t expect to find AC motor dynos anywhere except in NASCAR and F1 shops.
Chassis dynos have been evolving over the past decade. The days of the power-limited Claytons have been replaced by inertia type dynos. For the first time, cars producing more than 450 RWHP could be tested without smoking the tires and having five people pile on the trunk for traction. The large diameter inertia drums provided excellent traction, even for vehicles putting close to 1,000 hp to the rear wheels. Although the data was good and repeatable, tuners wanted a dyno to do steady-state-load testing capability (especially important for fuel mapping EFI) so inertia dyno companies like Dynojet added an eddy current mode, so the dyno can be run either way. Mustang, Superflow and Land & Sea have a strong presence in the chassis dyno market.
Mustang has several different units with their MD-1100 unit capable of handling 2,500 wheel horsepower and speeds of 225 mph. Land & Sea offers both 2WD and AWD chassis dynos with water brakes or eddy current absorbtion units. Superflow also offers a line of chassis dynos both 2WD and AWD capable of harnessing 2,500 hp and 225 mph. They use air-cooled eddy current absorbers, and offer extremely narrow track that is great for narrow rear end drag cars.
Regardless of which chassis dyno you consider, don’t simply go for the max power capacity − look at the rated load capacity that is usually much lower. Also look for features like the ability to run an automatic (computer controlled) sweep or step test. A few of these chassis dynos can simulate a 1/4-mile run or 0-60 blast from a standstill. There are several new innovations like Dynojet’s OBII interface that maps air fuel ratio, spark timing etc., which could be a big help in diagnosing problems.
One final note on chassis dynos both in-ground and above-ground models are easier to install and take up less space than traditional engine dynos. Chassis dynos can be a good drawing card for your engine building business, too. Lots of people just want a dyno pull on their vehicle for bragging rights, and you can host a car club meeting giving discounted dyno tests to club members − a great way to build a relationship with potential customers who would otherwise never darken your door. You could also run a local dyno challenge with awards or prizes. The local buzz can be incredible.
Another style of dyno not widely known is the direct couple chassis dynamometer from Dynapack. You jack the vehicle up, remove the wheels and bolt the wheel hubs up to the rolling power absorbers. It works equally well with 2WD and 4WD. Some of the advantages claimed by the manufacturer is that there is no wheel slip for more accurate readings, and when not being used it can be totally rolled out of the way, freeing up shop space. It has the capacity to handle virtually anything you can bolt to it with the ability to contain up to 3,200 hp and 7,000 ft.lbs. of torque.
Chassis dynos are great, but the ultimate tool for engine builders is the engine dyno. Like we said earlier, the most appropriate dynos (considering cost and capability) are the water brake styles led in popularity by Superflow’s 901/902 series, DTS’ Powermark and Land & Sea’s DYNOmite line. Stuska offers complete dynos with its Tackmaster LC and Go Power Systems offers turnkey systems as well. Here’s where you have to do a lot of your own research and see which dyno offers the features you need, at a price you can afford. If you are going to be running 2,900 hp Pro Mod motors with three stages of nitrous your needs will be very different from a shop running 750 hp normally aspirated circle track motors.
Land & Sea’s President Bob Bergeron offered this sage bit of advice “Buy an inexpensive (but modern design) dynamometer from a company that allows a modular upgrade path. However, remember: Hands down the most important part of any racing/research dynamometer package is the software. The buyer must make certain to thoroughly examine the software, as it will soon become the dyno to him! Software that does not have all the long-term capabilities, that almost all shops will eventually require, will force the shop to start all over again someday losing much of their investment of dollars, time, and that database of tests.”
Several top dyno manufacturers offer great entry-level deals to get you started. Superflow has a starter package that is good for 1,500 hp and 1,000 ft.lbs. for $26,950. It is a fixed “engine stand” model but should handle the majority of typical engine shop requirements. DTS offers its EM2000 model for $38,500 and is a “docking cart” model that enables an engine to be pre-installed on a cart then pushed up and attached to the power absorber. Docking carts are one of the latest innovations and most companies offer them. They are especially helpful when there are several engines scheduled for the dyno. Multiple carts minimize hook-up time you can be loading or removing an engine while another is running on the dyno.
Don’t forget the cost of everything else you will need, test cell, air supply, water supply, fire suppression it all adds up. The average investment will probably approach $50,000 - $100,000 for a new first-rate setup. Sure, you shop around for used systems or actually build your own out of commercially available components.
Regardless of how you do it, it is still a sizeable investment. So how do make money with one of these things? Typical rates for dyno testing an engine range from $500-$1,000. As a race engine builder you can simply roll the cost of the dyno time into the price of the engine. A racer paying $28,000 for a turnkey race engine isn’t going to quibble about another $1,000 to make sure it’s right. The same holds true for an engine being “freshened.” No one wants to go to the track with an unknown quantity under the hood.
Many shops have used their dyno as a promotional tool. Consumer magazines, websites and blogs are hurting for good tech information. If you are going to do a cylinder head or cam comparison test, shoot some good high resolution digital photos, document the information and submit it the magazine or website of your choice. Or even if you are building a one-off engine, reader interest in this stuff is high, and the credibility it brings to your shop is immeasurable.
Another way to market your dyno services is to tack it on as added value. Let’s say any engine over $10,000 gets dynoed for free. Any engine over $5,000 gets dynoed for just $500. Whatever the cost equation, the concept is to always add more value to your services without breaking the bank. Just do the math if your dyno cost $50,000, it’s going to cost you slightly more than 50 engine tests to break even. After that, you have years of added cash flow thanks to your dyno.
Regardless of how you approach adding a dyno to your shop, one thing is for certain it will make a better engine builder out of you. As your base of knowledge grows, you’ll learn what works and what doesn’t. A dyno will point you in the right direction to more horsepower and larger profits.
If you don’t need horsepower and torque numbers generated by a dyno but need to run and adjust an engine before it leaves your shop, a test stand is an excellent investment. In fact, some shops run their engines on test stands before they do a full dyno hookup to check for leaks and other unforeseen problems.
One of the best universal test stands on the market is built by Easy-Run. They offer three models (stages of completion) with the top model Professional Series complete and ready-to-run. It includes a heavy-duty radiator, 3-gallon fuel tank (adaptable for EFI), adjustable engine mount system, control panel with gauges, moveable battery tray and much more.
These accessories mount on a rugged powder coated stand with 6˝ casters rated at 800 lbs. capacity each. The stand can withstand extreme high output engines and can be test run with automatic transmissions attached. When you are through using the stand it collapses and stores in minutes.
Understanding The SpinTron
Advanced engine development, either for the race track or at the OE level, depends on the ability to test and simulate real-world conditions while in the laboratory. Only in a controlled and repeatable environment can accurate data be gleaned.
Certain areas, however, such as the study of the valve train while it operates at high engine speeds, have denied close examination until fairly recently. The SpinTron by Trend Performance changed all of that the behavior of every component responsible for valve actuation (either OHV or OHC) can now be examined, imaged and graphed in real time for analysis.
The SpinTron was born of necessity by Trend Performance’s owner and founder Bob Fox. Being desirous of creating the ultimate pushrod for racing applications, there seemed no way to improve its design other than hit-and-miss dyno testing. And when pushrod failure did occur, the reason was often unknown. For valve train technology to move forward, Fox recognized that a means to study the valve’s response to the profile of the camshaft was necessary. The SpinTron quickly revealed what was believed to be happening in the valve train was not the case.
At first glance the SpinTron resembles an engine dyno. There is, however, one huge difference where the water brake would reside there is a large electric motor concealed in the apparatus’ sheet metal housing. Instead of the engine working against a brake, the electric motor spins the crankshaft, which in turn runs the engine without fuel, ignition or combustion. The data acquired during the test procedures is processed and stored in the SpinTron’s computer.
When the test engine is mounted on the SpinTron it is fitted with a mandrel (dummy crankshaft) and a lubrication system. The lubricating system can be either of SpinTron origin or alternately of a conventional dry-sump arrangement.
There are two principal versions of the SpinTron: a gear-reduction model and a direct-drive model. The gear-reduction model, which is the most prevalent, is used principally for valve train testing and is offered with one of four electric motors: 25, 50, 75, or 100 horsepower. On the other hand the direct-drive model is equipped with a 150, 200, or 250 horsepower motor. It is used for spinning the entire engine, including pistons, and its principal function is to determine frictional loses.
With an optional torque arm attachment, this more powerful machine has the capacity to measure torsional deficiencies of internal components. The gear-reduction machine operates up to 11,000 rpm whereas the direct-drive model, which uses liquid-cooled electric motors, operates up to 12,000 rpm.
Regardless of the model of SpinTron, valve train analysis can be performed as a function of a Laser Valve Tracking System (LVTS) or, alternatively, through a very high-speed camera that captures up to 4,000 frames per second. The LVTS provides measurable data, for example, data displayed on a graph showing the magnitude and duration of valve openings referenced to the crankshaft position. The high-speed camera allows valve events to be viewed but not measured.
In addition, there is an optional high-speed data acquisition system that allows users to monitor all sorts of other events going on inside the engine. More information about the use of the SpinTron for valvespring testing will come in a future “Performance Notes” column.