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    Audie Technology's "Flow Quik" Product Review

    by Sean Brown


    Whether your a weekend racer or a professional engine builder, you probably already know how airflow is a key component in making horsepower. We've all heard how an engine is nothing more than an air pump, the more air/fuel mix it inhales, burns and exhales, the more power it makes. This fact is undeniably true and for years has prompted racers and engine builders alike, to develop ways of increasing the airflow potential of the engines they build. The goal is simple, get more burnable air/fuel mixture into the engine, get more power out.

    Unfortunately, this can prove easier said than done and without some form of instrumentation to quantify a given volume of airflow, substitution of, or modifications to an existing component of an engine will be derived from nothing more than guess work at best. Not surprisingly, this problem was realized long ago and out of necessity, a piece of equipment called an "Airflow Bench" was born. An airflow bench utilizes a vacuum source and various flow metering devises to draw air through engine components, in order to quantify the amount of air these components are capable of flowing. This acts as a tool to help engine builders match components of similar airflow capability and to asses the results of any modifications that may have been made in an effort to improve flow.

    A pre-manufactured flow bench can put one out anywhere from $2,500 - $10,000+ (even without accessories like computer integration) and for the average racer or budding engine builder, this can be a hard hit on the pocket book. Historically this has prompted racers to want to build their own, but without a degree in 3 applied sciences and a wealth of fabrication skills, this could amount to a nearly unconquerable task.

    Audie Technology of Norristown Pennsylvania (
    see sidebar) has what they believe to be, a solution designed to "fill the void" between a high dollar flow testing center and frankly, nothing at all. What they have done, is assembled a low cost, scaled down version of their professional level, data acquisition hardware and software into one easy to use package called Flow Quik. This would mean it is now possible for the average racer or engine builder to be doing genuine, reliable flow testing, for well under $1,000.

    What is it?  (Top of Page)

    The Flow Quik might best be described as a bare bones device for measuring flow volumes, (cubic feet per minute or cubic meters per minute) through a component such as a cylinder head, manifold, or carburetor. You must provide the vacuum source, some sort of head adapter and an airflow test plenum, which we will explain in great detail shortly. If you intend to test cylinder heads, you'll also need some way to open and close the valves, as well as measure this movement accurately. In short, the complete Flow Quik package includes the display unit/test section, 10 feet of flexible spiral bound hose, a calibration orifice and an 11 page instruction manual. If you purchased the optional software, you will receive a disk and manual for it as well.

    Flow Quik is also swirl meter and computer ready, if you have an IBM compatible computer, (286 or better) Audie has an optional program available to help in crunching the numbers Flow Quik generates. The software is currently in DOS, (with a windows version on the way) but provides many features worth considering. You can learn more about the software by clicking [here].

    How it Works (Top of Page)

    Flow Quik uses what is called an "averaging velocity tube" to measure airflow volumes through an engine component. The velocity tube functions much like an orifice plate, but poses significantly less restriction to the airflow. This allows the use of only one measuring section for a wide range of volumes and depressions, eliminating the need to stop and change orifice plates, or to switch between ranges as on a standard flow bench.

    Unlike a standard flow bench (which requires a standard difference of pressure between the atmosphere and the bench to be set, called the test depression), Flow Quik converts the flow being read real-time, to that which would occur at a standard test depression. You select this standard from the range control knob on the display unit and read the corrected CFM from the digital display. This eliminates time wasted in setting a standard depression level for each test or segment (valve lift point). It also allows the use of vacuum sources not having means by which to set a standard depression (like your vacuum cleaner).

    Getting Started (Top of Page)

    There are some things not included with the Flow Quik package you will need to get started. Assuming you are testing cylinder heads, the first will likely be a head adapter. A head adapter functions as a dummy cylinder to shroud the valves as on an actual engine, as well as provide a means of routing the airflow. The actual cylinder portion should equal at least 1.5 times the stroke of the engine for best results.

    A head adapter does not have to be complex. We made ours from 4" PVC drain pipe, this was in turn glued (via silicone caulking) to a piece of 3/4" plywood (see pictures). We used 3/8" carriage bolts to affix the unit to the cylinder head. By using the actual head gasket, we were able to line up the bore exactly, as well as effect a gas-tight seal. For odd sized cylinder bores, cardboard can be used with the next larger sized piece of drain pipe to "shrink" the cylinder to the size necessary. Do not stray too far off the actual size, or your readings will be incorrect.

    Now that you have a means by which to mount the head, you will need what is called an airflow test plenum. The test plenum is nothing more than a box, used to collect and dampen the airflow prior to measuring it. The plenum will dampen the effects of "head surge" and allow a stable source for Flow Quik to read the actual test depression. The only rules for the test plenum, are to make it strong enough, position the static depression tap in an area of static pressure (airflow not buffeting the pressure pick-up) and to position the outlet hose under the inlet area. You do not want the air to make a 90 degree turn inside the plenum box.

    At this point you should be able to measure the airflow, with some minor exceptions. Flow testing of cylinder heads is most often carried out in a sequence of valve lifts from .050" up to the maximum lift afforded by the cam (or further). A means by which to measure valve actuation accurately is therefore necessary. For our example head, we built a simple system from scrap steel. [See pictures here] If this proves beyond your capabilities, all is not lost. Several companies exist which are able to supply valve actuation and measurement equipment for most of the popular cylinder head designs. Many of these companies also supply pre-made head adapters and are listed at the end of this article. Failing that, you can get creative, we have also used stock adjustable rocker arms with the adjuster swapped out for a long bolt, the bolt is then tightened to actuate the valve. For overhead cam engines, shims added under the cam's base circle can be used as well.

    For accurate valve lift measurement, we recommend a 1 or 2" travel dial indicator be used. Do not try and skimp on measurement accuracy, or your numbers will not repeat as needed. While dial indicators are not expensive, it should be noted that a 1/4" - 20 bolt will move .050" per revolution, providing you have the means to fab something up. [see our example] It is important to make sure you can delineate exactly one turn every time.

    Rounding out the "must have" list includes, a vacuum source, some duct tape and modeling clay. You can use the clay for sealing leaks and making radiused inlet guides for the air to follow when testing inlet ports. Duct tape has a million uses, but here we will use it for sealing hoses etc. and this brings us to our vacuum source. In all cases, at least one large "wet-vac" drum-style vacuum cleaner should be used. Try to get one with the largest hose size and greatest power rating. If your valve size is much over 1.8" or your lift greater than around .500", you would probably want to consider the use of two (or more). If the depression drops too low, you will not only be asking more of Flow Quik's abilities, but the non-turbulent qualities of the flow could allow unrealistic results to be seen. Having said that, it was our finding that the repeatability was not altered with changes in test depression. So while the actual numbers may not match between tests taken at differing depression levels, either test would repeat indefinitely.

    Using the Flow Quik: (Top of Page)

    Using the Flow Quik is pretty straightforward in itself, there are a few things to note about it's operation worth mentioning. We'll highlight the good and bad points and give some tips to make things go easier.

    Time is of the Essence: (Top of Page)

    The first thing you will learn, is that the Flow Quik is fast, and in this regard, Audie has definitely held true to their word. You can literally test as quickly as you can open a valve and record the numbers. The conversion capabilities of the unit eliminate the need to figure CFM from percentages, therefore saving time after the test as well. With the optional software, you can graph your results within seconds of finishing a test.

    Because of the extreme speed at which you can test with Flow Quik, any inadequacies in your setup will be highlighted. You will be much further ahead to spend the time in making a good setup (test plenum, head adapter etc.) prior to attempting to test a cylinder head. If you don't, you will quickly become frustrated chasing leaks and wasting time with bogus results. If you do it right the first time, you will definitely be time and effort ahead.

    Checking for leaks is as simple as reading the display while the valves are closed, if you see anything over 00 CFM, then this is your leak. You must either seal the leak, or subtract that number from the test results at each test point. Using the software, you can actually record an average of the leak (if the leak is surging) and input the result, the software will then subtract the amount from each preceding test segment automatically.

    Sequence Of Events: (Top of Page)

    You must test in a specific order every time or you might get snagged up on a few things as we did our first time out. The first minor incident that occurred in our review, involved the sequence of operation. It is essential that the Flow Quik be turned on prior to the vacuum source! If the Flow Quik does not "see" a no-flow situation prior to beginning the test, the numbers will be wrong. In making that mistake, we achieved 250 CFM through a 1.625" valve, open .050". Since this head was our baseline head (stock) it would have been rather difficult to better those numbers! Lessen learned? Turn the Flow Quik on first!

    Calibration: (Top of Page)

    To calibrate the Flow Quik, you simply hook the included calibration orifice-tube to the end of the inlet hose supplied with the unit. It is a simple matter to turn everything on and then use the calibration knob on the back to set the flow reading to the required amount. This allows you to compensate for changes in the weather and make sure that your numbers will be accurate and repeatable. Additionally, we found the CMM scale more stable to calibrate with than the CFM scale, though either can be used as mentioned in the instructions.

    The next thing we found, was calibrating for the inlet side only did not necessarily work when switched over to test the exhaust flow! When asked, Audie mentioned this is a unique effect varying with each unit produced, but will not vary by more than the advertised accuracy. We found a difference of about 2 CFM when testing back and forth, which is only 2.5% and well below the 5% advertised accuracy. This inaccuracy is not really a problem unless you intend to compare your results with other published standards, or input the numbers into an engine simulation program like Dynomation or Engine Analyzer Pro. What is important, is that you stick to your method (either calibrating for one direction only, or stopping to calibrate both) or the results you generate will not be comparable, and repeatability is what counts.

    Lastly, we checked to see if the unit would agree with itself when set on different conversion ranges. After testing about five times and recording the results seen when each range was tried, we found (after punching a lot of calculator buttons) that the unit agreed with itself absolutely. So far so good.

    Validating The Numbers: (Top of Page)

    Thus far, the Audie Technology Flow Quik seems like a pretty hot ticket to high speed, affordable airflow testing. This however raises the question as to how the numbers Flow Quik generates, compare to that of an industry standard flow bench? We asked ourselves this very question and decided to put the Flow Quick up against an industry standard, Superflow 400 flow bench. We should be quick to mention however, that the purpose of this comparison was not so much to prove either system better than the other, but rather to validate the results seen by the Flow Quik, with something of a known standard.

    It may come as no surprise that Superflow is the dominate force in pre-manufactured flow benches. Since the beginning they have built a strong reputation for making benches that are accurate, quick to use, and repeatable, thus establishing themselves as the industry leader in flow measuring technology. We felt these grounds were reason enough to use the Superflow as an established standard in our comparison.

    The Test Piece: (Top of Page)

    We had a hard time choosing the exact engine component to make our comparison with, but finally decided on a 2300 Ford Pinto SOHC cylinder head with extensive port work. This head was modified for use in a mini-stock circle track application and was chosen on the basis of valve size and flow efficiency. We figured our 1.89" inlet valve size would be fairly representative of a wide variety of heads which could be used successfully with the unit. For these tests, our vacuum source consisted of two heavy-duty vacuum cleaners hooked together in parallel by a single PVC "T" fitting. Because of the low vacuum power for the flow volume, the depression would drop relatively low at the higher lift points, thus putting an increased demand on the Flow Quik's ability to compute the corrected flow volumes.

    Setting Up for Comparison: (Top of Page)

    Setting up for the two tests was relatively simple. In both we used the same valve actuation and measurement system, as well as the same size and type head adapter. We even used the same clay air entry horn for both tests to assure the results could not be skewed in this manor. The only differences in setup times, were directly as a consequence of the equipment in question. The Superflow takes up about 16 square feet of floor space, but provides instant-ready capabilities, set your head in place, clamp it down and begin testing. The flow quick can be as permanent, or as temporary as you prefer. If you want, it can be broken down and stored neatly out of the way where it will take up very little room. However, at the cost of increased floor space, could be increased time taken in setting up and breaking down the unit every time you feel the urge to go flow testing. So realizing the benefits of both, one has to make his/her own decision, therefore we did not include set-up time in our comparison.

    Making the comparison test was straightforward and to be fair, we did not use the software when making the comparison test, as doing so might noticeably shift the results in favor of the Flow Quik. This meant we would be manually reading and writing down the flow volumes, just as we would do with the Superflow. Once the tests were complete however, we did use the keyboard entry facility of the software, to graph and record the numbers seen in both tests and we'll show you that graph in a moment.

    Making the Tests  (Top of Page)

    Flow Quik:

    Using the Flow quik goes as follows. Be sure to turn the unit on first! Then with the valve closed, turn your vacuum on (or vacuums depending on the number used) to check for leaks. Begin opening the valve in the increments you desire and record the flow numbers shown for each sequential opening. As soon as you have all your test points and numbers written down, the test is complete. We chose to use the 28" of water range in order to make comparison of the numbers easier later on.


    Using the Superflow is a little more involved. First ensure there will not be any leaks, once certain of this, open your valve to the first test point and you're ready to begin. To actually test the flow, it will be necessary to choose a range. If you're lucky, you might get away with only one range, but if your port uses a wide range of flow volumes, you could easily need to use two sequentially as we did for our comparison. It is best to stay within the middle of the range specified or your numbers may vary in accuracy.

    Having chosen a range, you switch on the vacuum motors and open the vacuum control far enough to produce the correct test depression. For our tests, we used 28" of water as our test depression. The test depression is the difference in pressure between the atmosphere and the test plenum inside the flow bench. It is measured with a manometer, which is also built in. The depression is held constant for each valve opening point in order to make the numbers comparable and it must be held precisely or you will not generate the correct results. There is no compensation ability with the Superflow.

    With the depression set for the lift point, you read the percentage of flow from an inclined manometer. You must then use this percentage to figure the flow volumes from the maximum the selected range is capable of flowing. I.E. to compute a 200 CFM range percentage of 87%, we would write, 200 X .87 = 174 CFM. This procedure must be followed for each valve lift point, resetting the depression and calculating the percentage. If you find yourself out of range, you will need to stop and switch ranges before continuing.

    Results? (Top of Page)

    All in all, it took a conservative 12 minutes for one person to test the port with the Flow Quik. With two people operating, (one setting depression and the other recording numbers) we did the same inlet port on the Superflow in just under 25. By now, it should be seen that the Flow Quik is indeed quick in it's abilities to generate flow numbers. Want to see some test results? Click Here!.

    Looking at the results, it can be seen that the Flow Quik did not vary off the Superflow numbers by more than 3% at any given time. In Fact, the numbers varied by less than 2 CFM prior to the .350" lift point where the test depression on the Flow Quik dropped considerably lower than that of the Superflow. Whether this variance was due to a phenomena of airflow, or Flow Quik's abilities being spread too thinly remains to be seen, however the results are encouraging to say the least. The above accuracy is well within the advertised plus-or-minus 5%, even rivaling that of some larger manufacturer's entry-level benches.


    Conclusion: (Top of Page)

    For it's targeted market, the Audie Technology Flow Quik appears to be a worthy piece of flow testing equipment. The portability, effectiveness and speed of operation make the unit unique, as well as functional. Our findings showed the unit to be not only highly accurate for the cost, but extremely repeatable as well, making it the ideal piece for anyone attempting to improve cylinder heads or related components. For a racer, or anyone doing their own cylinder heads (even valve jobs), the use of an airflow testing device should be considered mandatory if true high-performance is the ultimate goal. Looking at the costs, the Flow Quik is a pretty cheap investment toward realizing these goals and earning the one-up on the competition. For engine builders, the unit allows an opportunity to not only improve the products delivered, but to also gain a more professional image with their customers. In any business situation, the Flow Quik should provide a nearly immediate return on investment by allowing an additional service to be included on the bill, if the customer so desires.

    Above all, we found the Flow Quik did exactly what it was advertised to do, well within the quoted accuracy limits. While the unit does require some fabrication effort on the part of the user, it is not extensive and could be made as complex or simple as one cares to take on. For those interested in making a more professional bench, the Flow Quik unit could be used as a measuring device in that application as well. Thinking imaginatively, the Flow Quik could fit into many applications and provide a wide range of benefits and possibilities.

    Flow Quik Software: (Top of Page)

    While the Flow Quik package is fully capable of being used without the optional software program, there are many advantages worth considering. As well as making actual flow testing quicker and easier, the Flow Quik software provides the user an ability to make professional looking graphs and multi-test data comparisons. The Flow Quik software is currently in DOS, but a Windows version is on the way. The software is also fully compatible with other Audie Technology programs, including Dynomation, allowing users to import flow graphs for direct computer simulation.

    Some of the highlights of the program include:

    • Nearly unlimited data storage, (depending on your hard drive space) allowing tests to be stored and called up whenever necessary.
    • Multiple configuration files allow different types of tests to be performed without need for reconfiguring flow limitations, etc.
    • Real time flow testing and graphing.
    • Time averaging ability to average "head surge."
    • Swirl meter ready.
    • Graphs include comparisons of CFM, percentages, area under the curve, lift to diameter ratios, port velocities, and more.
    • Print multiple reports and graphs, including comparisons, etc.

    Our biggest concern with the program initially lay with it's DOS interface. For those unfamiliar with DOS based programs, the Flow Quik software could easily be intimidating. We found however, that within possibly 2 hours or less we were starting to look (or at least feel) like computer pro's and our worries subsided. Once familiar with the environment, we found the software to be very useful for it's intended purposes, testing was fast and it was fun to be able to graph the results instantly at any time. You can truly look at numbers all day, but without a graph they can seem rather bland at best.

    For home users, hobbyists and racers on a budget, getting the software would probably be optional. Even if you do not use a dedicated "shop" computer for actual testing, you can still use your home computer via the keyboard entry facility as we did for the comparison tests in this article. Because of this, the software is still useful for comparison purposes and the fun of comparing and printing professional looking graphs. However, for the hobbyists, these elements alone may not pose a significant return on investment.

    For serious racers, head modifiers and engine builders, the software should probably be considered mandatory. There is nothing to add power to your elbow than the ability to print out high quality graphs and reports, proving your product better. Additionally, the added volume of work a professional business would generate could best be handled through computer storage of the information.

    All in all, the Flow Quik software is exemplary of the high quality products within the Audie Technology lineup. It's value for most users will be far greater than the purchase price. While we look forward to the Windows version, the DOS version reviewed here proved entirely functional and easy to use. An ideal accompaniment to the the complete Flow Quik package.

    Meet Audie Technology: (Top of Page)

    Those outside the hardcore racing industry may not recognize the name Audie Technology as a leading edge, performance industry stand out, but the company indeed has a strong reputation for delivering quality products aimed at a vast array of users.

    Having seen an opportunity to design a better software program for the then newly introduced Cam Doctor, Audie Thomas began Audie Technology in 1990, writing code in his spare time and developing the program soon to be known as Cam Pro. The program turned out to be a milestone that marked the beginning of the company's now extensive product line. Preferring to keep the business in his home - "I hate commuting" says Audie - Audie employs one other technician with his wife Teresa keeping the books and handling "a multitude of other tasks." Much of Audie's hardware and manufacturing jobs are sourced to trusted venders, however Audie is quick to point out that much assembly is done in house, as well as all final test and quality control. This allows them opportunity to keep a watchful eye over the products going out the door, ensuring the customer of a top notch product at a reasonable price.

    With an enthusiastic attitude denoted by comments of being a "work-aholic", Audie has continually strived to develop useful software programs, designed to interact with each other, as well as both pre-existing and supplied hardware for markets as diverse as hobbyists and race teams, to OEM's and technical schools. The addition of their website (www.audietech.com) has allowed the company to provide a greater depth of information at less cost to the customer. Adds Audie, "Another great use of the website is distributing software updates. Our customers can go to our website anytime, and download an update to the latest version for any of our Windows programs that they own." Audie is quick to note that enthusiasm doesn't end with the sale, customers are encouraged to write or call at any time they need assistance. This open-door policy has been a trademark of the operation since the beginning, allowing the company to enjoy the merits of repeat sales and word of mouth advertising.

    Interview (Top of Page)

    Audie Thomas gave me this interview to answer questions about the history and technicalities of the Flow Quik, included below is that interview.

    SB: How did you come up with the idea for the Flow Quik, what was the motivation?
    AT: The motivation was to provide our customers with a good tool. The general idea came from two independent sources. Dave Vizard shared a story with me about someone he knew that had a flow setup that used a vacuum cleaner. Shortly after that, our sales rep in South Africa was here for the PRI trade show. He shared similar ideas. It took a lot of development effort to turn those ideas into reality.

    SB: What market was the Flow Quik intended for and what market does it now fill?
    AT: It was intended to be a "starter unit" that would be used by the hobbyist. I expected some of these people to later "go pro" and buy a regular flow bench. Flow Quik works so well that few owners have moved on to a regular bench, and many Flow Quik owners are standard businesses. We even have some customers who already had a standard bench and needed another bench.

    SB: How long have you been selling the Flow Quik?
    AT: Since 1996.

    SB: How many units have you sold?
    AT: Several hundred.

    SB: SuperFlow, FlowData, and other flow bench companies advertise a specific percentage of accuracy for their products, do you do the same and if so, what is the accuracy percentage for the regular and larger model Flow Quik?

    AT: Advertised accuracy is +/- 5% of reading. Advertised repeatability is +/- 1% of reading. The advertised specs are conservative.

    SB: Does the accuracy or repeatability change with test depression? What about flow turbulence, or surging?

    AT: When working with air flow, you quickly learn that everything has some effect. Flow Quik is designed to automatically compensate when depression changes. This makes it more repeatable and much easier to use than a standard flow bench. Compensation works best when it is not abused. You will get better results if you keep depressions within a few inches of your standard depression. Turbulence is best handled by using the time averaging ability of the Flow Quik software.

    SB: What minimum and maximum CFM ratings will the Flow Quik accurately work within?

    AT: The standard Flow Quik can flow 330 CFM. The large model can flow over 700 CFM. These specs do not have "at 28 inches" in them since it does not apply. A spec like "600 CFM at 28 inches" applies to a vacuum source. With Flow Quik the customer supplies the vacuum source. When we say the standard Flow Quik can flow 330 CFM, we mean that if you apply enough vacuum to it, you can get 330 CFM through it, but not much more, no matter how much vacuum you apply.

    SB: When should one consider the larger model over the standard one? How would a customer determine this?

    AT: The larger unit gives up some sensitivity (especially at very low flow rates) to gain more total flow. If your heads mostly flow less than 330 CFM, or your air supply can not move much more than 330 CFM then you should use the standard unit. As a rough rule of thumb, valve diameters below 2.100 inches will flow under 330 CFM. Installing the larger unit is more difficult, but still easily within the capabilities of anyone who works with engines.

    SB: Is the standard unit upgradeable to the larger size?
    AT: We can do a retrofit.

    SB: Is it possible to use the larger test piece with the regular Flow Quik display and vice versa?

    AT: We have some Flow Quiks that use both size flow tubes. We do this by "stealing" the metric ranges and using them for CFM with the larger flow tube.

    SB: What tubing length is necessary prior to the test piece inlet for accurate results and will additional lengths increase or decrease accuracy?
    AT: One foot minimum for the standard Flow Quik. Two feet of straight pipe on both ends of the larger flow tube. Longer lengths will not hurt. These lengths apply even when using a test plenum.

    SB: Is a test plenum necessary in all cases?

    AT: You get the best results when you use a test plenum to mount your head and head adapter. A "test plenum" is an empty box with a hole in the top and a hole in the bottom. You mount the head adapter on the hole in the top. You connect the hose or pipe from Flow Quik to the hole in the bottom. Flow Quik's depression pickup is placed in the box so that it sees the same depression that the head sees, but is not buffeted by the air flow. This arrangement closely matches that typically used by flow benches. Details on hole sizes are listed in our website.

    List of contacts mentioned in this article: (Top of Page)

    Superflow Corporation

    3512 North Tejon

    Colorado Springs, CO 80907


    Mondello Technical School

    830 21st. Street

    Paso Robles, CA 93446

    Phone 805-237-9185

    Fax 805-237-9154


    Brzezinski Racing Products

    N50 W23001 Betker Drive

    Pewakee, WI 53072

    Phone 414-246-8577


    Dwyer Instruments Inc.

    PO Box 373

    Michigan City, IN 46360



    Bill Jones

    3294 Meadow Wood Way

    Salt Lake City, UT 84118

    Phone 801-969-3807


    Meriam Instruments

    10920 Madison Ave.

    Cleveland, OH 44102



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