Dynamometers allow an engine builder to test, tune and tweak his engines before giving customers the opportunity to do something foolish with them.
In a recent poll on Engine Builder’s website, we asked our readers how important a dyno is to their business. According to our (admittedly unscientific) results, 44 percent of Engine Builder readers couldn’t survive without it, 52 percent have a burning desire to get one and only 4 percent see it as an occasional-use type item.
Where dynos were once considered a luxury available only to certain elite engine builders and mad scientist performance experts, some people suggest that a dyno has become an absolute business necessity, not just for performance engine builders and racers, but for all types of engine builders.
“Building a performance engine today without a dyno is like driving at night without a road map,” suggests Engine Builder Technical Editor Larry Carley. “You know where you want to end up but may not be sure of the best route to your final destination. And since real men never ask for directions, you may make a lot of wrong turns along the way, leaving you unsure where you are at any given moment.”
Carley acknowledges the value that years of experience brings with regard to determining that certain combinations of parts can produce certain levels of horsepower. But how do you know for sure? How much horsepower? Could the engine make more power or have a better torque curve if you tried something different? There are a lot of questions, all of which can be answered through proper use of a dynamometer.
There are many different styles of dynos available, but the main goal of any of them is simple. According to David Manzolini, Depac Corp., “Simply try to fool the engine into ‘acting like’ it is running in the intended application. There is no ‘one-size-fits-all’ dyno. The different types of dynos have evolved based on needs. The stand-alone engine test cells provide the maximum possible controls. Chassis dynos are quick, easy, and a practical complement to the engine test cell to sort out the whole package.”
Profit Center or Business Black Hole?
Let’s face it: dynamometers aren’t exactly the cheapest machine in the catalog. Engine builders should remember that the value a dyno can provide is related to many factors, not simply the fact that you have one. One of the main questions that need to be asked is, for your business, can a dyno be a profit center or is it just a tool that serves as a means to an end? Experts insist that it can be both.
“Absolutely it can be a profit center,” says Steve Matthiesen at SuperFlow. “We have thousands of customers who use the dyno as a profit center. It increases credibility and instills confidence in your customer that you know how to get the most from their engine or vehicle and you are selling them the right product.”
Manzolini says “DEPAC has tried to teach its many customers that their dyno can be a good profit center IF they can demonstrate the ability to understand and make proper tuning changes.”
He says that today’s engine builders have done such a good job developing their products, that big improvements may no longer be possible. “On many well-developed engines there are no more ‘big changes.’ DEPAC equipped dynos have the potential, with better understanding, to show smaller tuning changes. Being able to find 10 small changes can add up to a big improvement, though, and being able to see and understand these changes is key and the standard OEM dyno cannot show these small changes. An engine builder can get much repeat traffic if he can turn a 10th place car into a consistent winner, even though his dyno numbers may be much less than advertised by a competitor.”
Manzolini is quick to offer one suggestion up front that engine builders should remember: “Avoid developing a dyno-only engine, one that only runs well on the dyno.”
According to Matt Schultz at Stuska, “An engine dyno is no less important than machining equipment in today’s shop. Information is an integral part of being successful in this business and a dyno is how you get that information.”
However, Schultz says there is a whole other side to getting the most out of a dyno besides the “numbers” it can provide. Equally important, look at it from a marketing perspective. While it can cost a lot of money, it should be looked at as an investment.
“An engine dyno should not be viewed as an expense for a shop but as a profit center and part of a business and marketing plan. If a conscious decision is made to integrate engine dyno services into your business, it will increase your profits! Many shops fail to market the dyno, and benefits of having one, to their potential,” Schultz says.
“For those who take their engines to another shop to be tested, there are additional advantages. Consider the following: The time it takes to cart the engine to another shop and back, the cost of the travel itself, the inconvenience of working in someone else’s shop and using their tools/equipment. Who is running your shop/answering the phone when you’re gone? Do you want your competitor getting a peak at your speed secrets? I have had people in remote areas tell me that they are driving up to 5 hours one way to dyno their engines. You don’t have to make many trips per year at this pace to justify the investment in your own dyno,” Schultz says.
Kevin Gertgen at Performance Trends agrees that the marketing opportunities are great. “It offers significantly increased value to your engine builds when you can provide computer printouts of a power curve for the customer’s engine. Being able to say “dyno tuned” allows you to charge more for your services. Plus you may get ‘walk-in work” from the guy who just wants to see what his engine or vehicle will do. This is especially true for chassis dynos.”
According to Dan Roberts at DTS, the question isn’t “will a dyno increase business?” but “how much?” “Every new customer of DTS has said that once they installed their dynamometer system their business increased. Some sell dyno time while some do not, but whichever way they have their business configured the dyno is a moneymaker.”
Roberts also suggests considering what a dynamometer can save in comebacks and engine problems. “You won’t get customers saying ‘Hey it ran fine when it left here. What did you do?’”
While dynos are often thought of as a great way to test an engine and break in cams or rings, Al Freilich at Easy-Run Engine Stands says using a dyno for such a purpose can be counter productive.
“Most engine builders and restoration shops prefer to know that the engine has been certified either on a dyno or on a run stand,” says Freilich. “The risk factor is too great today with the high cost of parts, labor and company reputation to send out an engine that has not been proven.”
However, he says “I would be very surprised to see anyone just spend the money for break-in time only. Normal break in time is about 20-30 minutes, where a builder would torque bolts, check gaskets and then run for at least another hour. On a dyno, $150 per hour gets expensive for just break in.”
A run stand like Freilich’s (which has universal mounting capability for virtually any engine) gives builders the chance to ensure the engine is ready to go before spending the time and money on a dyno pull. And, in Freilich’s view, it should do so easily and safely.
“Engine run stands should be safe to operate, (should not need to stand between the headers to view the control panel or in front of the radiator and reach across the fan belt area while viewing to operate the carb) give great engine visibility during the run cycle while viewing gauges and master shut down switch, provide excellent room for repairs when needed, must be able to load, run and remove the engine quickly to be profitable. Adaptability is a must as no one wants to spend big dollars and be limited to its use.”
Freilich’s continues, “When possible, the run stand should be easy to store for the shop that is limited on floor space. The run stand should provide its customer with everything possible to make the assembly easy and complete. Adjustability is a key factor: The radiator must be able to be above the highest cooling system requirement to reduce air pockets (intake manifold cooling passages). The engine mounting system should accommodate anything from a 4 cylinder, V6 to an 8 cylinder or larger engine. That means very adjustable cross members and mounting system are a must.”
Freilich says another advantage a properly equipped test stand can provide is the ability to heat cycle the engine many times. “The Easy-Run permits you to have extended engine runs, completely cool the engine many times and verify the gaskets, seal and block plugs are all sealing correctly, valve adjustment is correct, timing is correct, importantly that there is no vacuum leaks causing a lean engine condition, use of an air fuel ratio gauge in the exhaust will help with a good starting point for jetting and it makes a nice tool for breaking in new set of headers so as not to ruin the coating as per many header manufacturers,” he explains.
“Dynamometers are targeted towards specific applications,” explains Virginia Bergeron at Land and Sea. “While there is certainly some overlap, the right tool needs to be used for the specific testing job. For example, AC based chassis and engine dynamometers are able to motor the engine this allows simulating coast-down conditions and is vital for evaluating complex hybrid driveline behavior. Reaction-cradle systems provide near instantaneous capture of torque transients, etc. On-board torque measurements bring the dyno out onto the drag strip or race course.
Getting the Most From Your Dyno
It might seem surprising that one of the country’s leading dyno facilities would sing the praises not of its dyno but of the Easy-Run Stand. But Freilich says large dyno facilities often have problems with guys who fancy themselves engine builders but are really only parts assemblers.
“The biggest things one of my contacts sees is the average guy (not the pro engine builder) who builds an engine, maybe puts in a cam and carburetor and wants to see how much horsepower it has. He takes it to the dyno shop who finds a few things: 1. The distributor is often put in exactly backward; 2. Since the engine hasn’t been fired, the manifolds and sealed surfaces start moving around and they have to go around and retighten everything; 3. Some of the engines haven’t been primed, etc.
“A lot of times, they just bring it to him and leave it. He then he has to call them and say it didn’t fire,” Freilich says.
He also explains a more serious potential prolem, “Let’s say it’s an older motor with a two-piece rear main and for whatever reason, it leaks. Now he has some oil in the dyno room, maybe a little contamination depending on how bad it is. He has to call the customer and say ‘You need to fix these issues before we can do a serious pull, because we don’t want to have a problem on the dyno.’ Now the customer is mad, has to drive back and pick it up, make the corrections he thinks are needed and then take it back and still not know for sure whether he’s fixed his problems or not.”
Simply put, Freilich and many dyno operators are making the effort to encourage people to run their engines before taking them to the dyno facility.
“Even professionally prepared engines can have some surfacing issues where valve covers or intake manifolds may not seat to the heads or block perfectly and may have vacuum leaks under the intake manifold so it’s sucking oil and doesn’t run right,” Freilich says. “If the guys have the ability to run the engine for a period of time on the stand, they’ll know whether it’s ready to go to the dyno or into the vehicle.”
Or consider that you build an engine for your customer and haven’t fired it. You send it off, he slides it into the car and all of sudden the intake manifolds or cylinder heads aren’t seating correctly. Now who has the problem? Is it the engine builder or the engine buyer? Actually, it’s probably both and EVERYBODY’S unhappy. “The list of the complaints we hear about things like this from people goes on and on and on,” says Freilich.
Tips From Suppliers on Using Dynos Effectively
Dan Roberts from DTS says, “For good, repeatable data the operator needs to run the engine every time in as close as possible the same conditions. He must look at oil and engine coolant temperature and inlet air temperature is the most common to be the same every test. The DTS software display allows the operator to set up a ‘window of opportunity’ on every channel. He can set his oil temperature to be with in a three-degree window, for example. The display changes color so when oil temperature in not in the window it will be a different color than when it is in the window. When all channels are in the color of the window the operator knows he can initiate the test without having to actually look at what the numbers are.”
Roberts agrees that it can be difficult to compare data from one facility to another as conditions will likely not be the same. “Air, room size, exhaust system, etc., all have an affect on an engine’s performance,” says Roberts. “Facilities with multiple test cells usually are pretty close. At the Engine Masters Challenge held at World Product’s facility, all three DTS test cells were within one horsepower of each other. At a facility like Roush Yates Racing Engines, their six DTS cells are almost identical…but that is because they utilize DynoAir, which conditions the engine’s inlet air so every engine, every test cell and every test has the exact same air condition day in and day out. Smaller engine shops usually do not utilize DynoAir as it is extremely expensive.”
Roberts and others say the “correction factor” issue required to compare different dynamometer facilities “opens a huge can of worms, and I nor do you have the time or paper to go into that at this point. If you’re testing an engine and doing any sort of R&D it’s best to use one facility and best to do the R&D in the same day and not use correction factors. A number is a number the engine will not see the same conditions once it is installed in its application as it saw on the dyno.”
Matthiesen from SuperFlow explains that certain parameters must be recognized by an operator to produce accurate results. “Controlling the variables is No.1. If you want a dyno to repeat then you have to be sure that each and every test is performed in the same manner and under the same environmental conditions as well as the engine/vehicle temps are the same. When the results are different than expected, does the operator blame the dyno or does he look for other reasons why the power is down? We teach our operators to understand that a dyno is a tool and a very reliable and repeatable tool. When they see a ‘blip’ in one test versus another, there is usually a good reason and usually it is not the dyno. It could be the ABS/stability control decided to retard the spark since the front rolls were turning a different speed than the rear rolls. In the case of the SuperFlow chassis dynos, we mechanically connect the front rolls to the rear rolls so the ABS/stability control never sees the driveline ‘windup.’ Or Joe Cool, your favorite customer, comes in with his Porsche sporting new tires and wheels, makes a couple of pulls on your dyno and decides that your dyno is broken because the car doesn’t make the advertised HP that he paid $110,000 for. What he didn’t say is that his Zoot Capri new tires/new wheels all together weigh 100 lbs more than the original new tires/new wheels. Believe it or not, today’s dynos can see the HP difference to the roll surface due to the changes in rotating mass. It makes a difference.”
How similar are the results from one dyno to another? “It depends on the type of dyno,” says Mattiesen. “An engine dyno will show you the highest HP and torque number since we have taken the driveline, tires, rolls out of the equation and the HP and torque results will be very accurate. A chassis dyno will provide you with better real world power from tire to ground results but you have to temper that with the size of the rolls, how hard was the vehicle tied down to the rolls and what kind of test was done on the chassis dyno. Was it a simulated drag test or a steady state test? Neither test will show the same numbers. And there is always all the parasitic loss in the driveline… from exotic oils in the engine to what kind of oil was run in the transmission. SuperFlow offers software that can reasonably approximate the engine power at the flywheel by performing a ‘coastdown’ test while on the chassis dyno that measures the driveline losses and then from the results of the coastdown test back calculates the engine power and torque.”
Kevin Gertgen from Performance Trends reminds readers that there is a difference between accuracy and repeatability. “Accuracy means that if you report 500 HP, the National Bureau of Standards in Washington, DC would agree it makes 500 HP. Repeatability means that your dyno may report that 500 HP engine as making 520 HP, but it repeats that 520 HP within 1 HP any day of the week. This means you have a very repeatable dyno, which is typically more important for developing strong race engines. Actually, the 500 HP dyno may say 495 one day and 505 HP the next. It is actually more accurate at reporting something close to the actual 500 HP even though it is not as repeatable as the 520 HP dyno.”
In Gertgen’s opinion, the best way to achieve both is to everything exactly the same from test to test. “Oil and water or head temperature must be the same at the start of the run. The acceleration rate must be the same. This is what gives the inexpensive, simple inertia dyno a big advantage in repeatability. It is so simple and accelerates so smoothly, there is really very little which can change from run to run.”
Exactly, says Matt Schultz at Stuska. “I think it’s important to make a distinction between accurate results and repeatable results. It is repeatability that we are looking for. It is easy to define and without it a dyno is useless. Accuracy, on the other hand is almost impossible to define. There is no universal set of standards for accuracy. To obtain repeatable results, the testing conditions need to be repeated from one run to the next. This means, among many other things, the air quality, oil temperature and water temperature all need to be duplicated to the best of your ability.
Depac’s David Manzolini agrees that controlling conditions is key. “You must be able to control conditions that affect the results. Thinking conditions are OK can be misleading when they are not. I see too many air systems that are very bad even though the operator ‘thinks’ it’s OK. The testing technique or procedure can be very bad. Simply repeating the same bad procedure does not compensate, as much as many would like to think. Then, you must be able to distinguish whether the engine is running very erratically and possibly why. Everybody thinks their engine runs perfect but in reality it produces random results, that can vary from .001% to really bad, more than 10% errors. The better combination of components and good engine design will have less performance scatter.
DEPAC displays performance scatter as a pattern of Machine-Gun dots for Trq-Pwr on the grafplot screen (see the GrafPlot explained here http://www.depac.com/depac-method.htm). It shows what the engine is really doing, like it or not. DEPAC does not pre-filter (or distort) the information or smooth the resulting curves. Our method produce quality results that are very significant. Inertia cause errors on any torque seeps can be very significant.. DEPAC can easily remove any inertia errors so the engines true performance can be shown. A heavy flywheel can easily smooth or filter the torque scatter of an engine. DEPAC’s very effective inertia corrections can completely remove the filtering effect of the flywheel. See the 2 curves mentioned above where the engine is swept up and down quickly yet they are with 1/100% on average even though the average inertia errors would be 5% with our very effective compensation.”
While it is real-world results that matter, it’s dyno results that some enthusiasts use as bragging rights. Virginia Bergeron from Land and Sea agrees that good software will return reliable results. “Surprisingly, the dynamometer’s software (along with the operator’s ability to use it correctly) is one of the biggest factors in producing usable results. A dyno with poor software acts like a straightjacket to the operator’s abilities. Be sure to evaluate the software thoroughly before selecting a dynamometer.”
Bergeron says in most cases dynamometer results should compare. “The math and functionality are the same. The dyno operator is usually the biggest reason for variation in dynamometer results. Attention to details such as weather correction temperatures, etc., are the biggest culprits. As long as the operator is honest, proficient with the usage of the equipment, and has a good understanding of the input parameters – the results should be consistent.
That said, a few dyno manufacturers choose to inflate their power readings (by 10% to 15%) to make “happy” customers! No legitimate dynamometer manufacturer should play such games and specifically, DYNOmite Dynamometers do not do this.”
SuperFlow’s Matthiesen says, “It is proven time and time again that a competent operator instills confidence and credibility in his place of business. We provide the operator of our dynos upon successful completion of training a ‘SuperFlow Certified Dynamometer Certificate.’ This ensures that this operator knows our equipment as well as the theory and operation of SuperFlow dynos. In most cases training consists of 2 days but in some cases it can be as much as 3-4 days depending on the system.
Should you get your own dyno? Obviously, that’s a tough question, but the potential upside is strong, especially if you remember its powerful marketing aspects.
“What are you marketing?” asks Stuska’s Schultz. “The first is quality control. Not only are you verifying the performance of the engine, but you can also check for leaks and resolve fine-tuning issues or potential problems before the customer receives the engine. A dyno builds customer confidence in your workmanship. Use the dyno as a showpiece and attention grabber for your shop. Have an open house in the off-season and run an engine for potential customers. When they hear the engine and smell the burned race fuel they will get motivated to buy. Dyno every engine whether it’s new, or a rebuild and have the fee built into the package price. In the long run, this will make you more money, increase quality and customer satisfaction.”
Schultz concludes: “Work smarter not harder. In today’s economy you need every tool you can get to differentiate yourself from your competition.”
Useful Test Stand Tips
Al Freilich from Easy-Run Engine Stands suggests ways a quality engine stand can improve customer satisfaction as well:
Guys take them to swap meets and rent them out. Somebody may want to buy a motor but wants to see if it works first.
You can mount the entire engine and transmission combo (either automatic or stick). This helps restoration guys who may not be able to find the right bellhousing. It’s pretty tough to find a stick bellhousing for an old Chrysler. But chances are they have an automatic or they’re converting an old Hemi by putting the Turbo 400 behind it. You can run it through the gears and make sure everything is shifting. You can check front pump seals, and more importantly, especially with the Chrysler guys,there are about a half-dozen converter/crankshaft combinations out there. If you match the wrong converter with the wrong crankshaft you wind up with a converter vibration. This is a fairly common problem with Chryslers and some Fords. A restoration shop in North Carolina has been using our stand and has found a bunch of these problems because customers will bring them all these parts and you never know for sure if they’re right. They’ll run it all on the run stand before they slide it down in this finished body. It saves them time and problems.
Here’s a tip for GM guys if you’re doing a bunch of GM engines, you can go to a wrecking yard, get a universal GM turbo 350 or R200 tranny case and do pretty much any GM engine. Pontiac and Buick starters are on the drivers side; Chevy’s starter is on the passenger side. All you need is an automatic case, put it on with mounting we provide and you can do a lot of different engines.
We can’t possibly supply every different fitting to mount the hoses and fittings but the engine mounts on the Easy-Run stand are adjustable and the radiator can be moved up or down, so you can typically use the stock hoses.
You can run the engine through acceleration, accomplishing what many people thought only a dyno was capable of.
When you’re comparing a dyno to an engine run stand, yes they both have their place. Unfortunately, some run stands have taken a beating over the years we’ve all seen pictures of engine builders hanging their engines from trees, or from swingsets…that’s the image we want to help people stay away from. Easy-Run’s goals are to take it to a level that gives you, the engine builder, more professionalism.