The following information may be helpful in answering questions and solving problems that you encounter when installing and using the DynoSim. If you donít find an answer to your problem here, send in the Mail/Fax Tech Support Form in the DynoSim Users Manual (ProRacing Sim Software provides Mail/Fax technical service to registered users only mail in your registration form today). We will review your problem and return an answer to you as soon as possible.



Question: DynoSim won't run and produces an error messge stating that a .DLL file is missing.

Answer: Some Windows installations do not have the correct versions of required dynamic-linking library files needed for the DynoSim to operate properly. If you are using the DynoSim and you've received a message indicating that a ".dll" file is missing, download program updaters here. After the download is complete, double-click on the Updater to add the necessary files and patches. If all else fails, upgrade Windows and make sure Internet Explorer is installed and working (do not uninstall Internet Explorer as this removes essential system files).

Question: Received an "Error Reading Drive D" (or another drive) message when attempting to run or install the DynoSim. What does this mean?

Answer: This means your computer cannot read the disk in your CD-ROM drive. The disk may not be properly seated in your drive, the drive may be defective, or the disk may be damaged. If you can properly read other CD-ROM disks in your drive, but the DynoSim distribution disk produces error messages, try requesting a directory of a known-good disk by entering DIR X: or CHKDSK X: (where X is the drive letter of your CD-ROM drive) and then perform those same operations with the DynoSim disk. If these operations produce an error message only when using the DynoSim disk, the disk is defective. Return the disk to ProRacing Sim Software for a free replacement (address at bottom of Tech Support Form).

Question: Received a "Canít find E:\SETUP.EXE..." (or another drive) message when attempting to install the DynoSim. What does this mean?

This means your computer cannot find the install files on the DynoSim disk your CD-ROM drive. The problem is due to an outdated CD-ROM drive or driver software. You can get around this program by creating a TEMP folder on your hard drive. Use the Windows Explorer to copy all files from the DynoSim CD-ROM to the TEMP directory (youíll need about 350MB of free disk space to complete this process). Then run the SETUP.EXE file from the TEMP directory. When the installation is complete, delete the TEMP folder.

Question: After installing the DynoSim (using Compact or Custom install options) I am unable to access the DeskTop Software Video files from the HELP menu in the DynoSim. I get a message referring me to the Installation Guide or Users Manual. How do I fix this problem?

Answer: Reinstall the DynoSim from the CD-ROM. When you are presented with the three install options (Typical, Compact, Custom) choose Custom. Then remove the check marks from all files except the DeskTop Software Videos. Continue the installation to reinstall just the Video files.

Question: When I tried to access the Users Manual from the Help menu in the DynoSim, I get an error message that says that Adobe Reader can not be found in the registry. How to I access the Users Manual?

Answer: You need to install Adobe Reader on your system. Double click on the AR3W95.EXE (or AR4W95.EXE) file located in the Acroread folder on the DynoSim CD-ROM. This will install Reader (or go back to the support page to download the same file). After installation is complete, you can open the DynoSim Users Manual by selecting User Manual from the DynoSim Help menu or select Users Manual from the Start, Programs, DynoSim Windows menus.

Question: Encountered "Could not locate the DynoSim CD-ROM" disk error message when trying to run the DynoSim. Why?

Answer: Please insert the DynoSim disk in your CD-ROM drive. Occasionally, the DynoSim will need to access the CD. Please keep the DynoSim disk handy.

Question: The DynoSim produced an Assertion Failure error. What should I do?

Answer: Please note down all of the information presented in the message box, provide a quick synopsis of what lead up to the error, include the version of your software, then send this information to ProRacing Sim Software. Thank you for your assistance in helping us improve the DynoSim. Also, download program updaters here. They eliminate several Assertion Failures.


Question: Everyone talks about how longer rods make more power. Why isnít rod length one of the choices in the pull-down menus?

Answer: Tests we have performed with the DynoSim show that rod length has virtually no affect on power. We realize that many actual dyno tests have shown power increases, but our simulation tests tell us that the power, when found, probably has little to do with piston dwell at TDC (and the associated thermodynamic effects) or changes in rod angularity on the crank pin. The measured power differences are most likely due to a reduction of friction on the cylinderwall from changes in side-loading on the piston. This can vary with bore finish, ring stability, piston shape, the frictional properties of the lubricant, etc. These variabilities are highly unpredictable. Some development, after all, can only be done in the real world on a engine dynamometer.


Question: The DynoSim calculated the total Combustion Volume at 92ccs. But I know my cylinder heads have only 75ccs. Whatís wrong with the software?

Answer: The confusion comes from assuming that the calculated Total Combustion Volume displayed in the component-selection screen is the same as your measured combustion-chamber volume. The Total Combustion Volume is the entire volume that remains in the cylinder when the piston reaches top dead center. See page 25 in the User Guide for more information about compression volumes.


Question: When I choose a carburetor that is too large for an engine (for example 1200cfm on a 283 Chevy), why does the power increase without the typically seen "bog" at low speeds?

Answer The DynoSim, along with virtually any current computer simulation program, cannot model over-carburetion and show the usual reduction in low-end performance that this causes. In reality, carburetors that are too large for an engine develop fuel atomization and air/fuel ratio instabilities, phenomena that is carburetor specific and extremely difficult to model. The DynoSim assumes an optimum air/fuel ratio regardless of the selected CFM rating. While the program produces positive results from larger-and-larger induction flows (by the way, this is not far from reality when optimum air/fuel ratios can be maintained, as is the case in electronic fuel-injection systems), you canít go wrong if you use common sense when selecting induction/carburetor flow capacities.

Question: The engine I am building uses two 660-cfm Holley carburetors. How can I simulate the airflow?

Answer: The DynoSim will simulate induction airflow from 100 to 3000cfm, rated at either standard 4-barrel pressure drop of 1.5-inches of mercury or at standard 2-barrel pressure drop of 3.0-inches of mercury (a pressure drop of 1 inch of mercury is equivalent to 13.55 inches of water). To simulate two, 660cfm, 4-barrel carburetors, simply add the airflow and enter the total 1320cfm value into the component-selection screen (make sure the pressure drop shown in the INDUCTION category is 1.5-in/Hg).

Question: I am working on some custom 2-barrel carbs. My buddy has a flow bench and has tested some of my handiwork, but he used a pressure drop of 30 inches of water instead of the "standard" 3-inches of mercury. Can I convert these flow numbers to 1.5-inches of mercury so that I can test them in the Dyno?

Answer: Yes. Use the AirFlow calculator incorporated in the DynoSim version 3.08 and later. Download program updaters here.


Question: I built a relatively stock engine but installed a drag-race camshaft. The engine only produced 9 hp @ Sim rpm. Is this correct?

Answer: Yes. Very low power outputs at low engine speeds occur when radical camshafts are used without complementary components, such as high-flow cylinder heads, high compression ratios, and exhaust system components that match the performance potential of the cam. In fact, some low performance engines with radical camshafts will show zero horsepower at low speeds. This means that if the engine was assembled and installed on a dynamometer, it would not produce enough power to offset any measurable load.

Question: The horsepower produced when I enter the seat-to-seat timing on my cam card does not match the horsepower when I enter the 0.050-inch timing figures for the same camshaft. Why are there differences?

Answer The DynoSim uses the timing specs found on your cam card, and in cam manufacturerís catalogs, to develop a valve-motion curve (and from this, develops the instantaneous airflow for each port). Neither the seat-to-seat nor 0.050-inch timing figures precisely describe actual valve motion; you would need to measure valve position at each degree of crank rotation to come close to developing an exact valve-motion diagram! Lacking this, the DynoSim "creates" its own seat-to-seat valve-motion diagram for use in later calculations of power and torque. A lot can happen in induction airflow between the time the valve rests on the seat and when is reaches 0.050-inch of lifter rise. When in doubt, use seat-to-seat timing figures. They provide the DynoSim more information about valve motion at low lifts, and are more likely to produce accurate simulated power levels.

Question: How does the DynoSim allow for hydraulic, solid, and roller lifters?

Answer: The DynoSim calculates a valve-motion diagram that is used in subsequent calculations to predict horsepower and torque. When the choice is made to move from hydraulic to solid, and then from solid to roller lifters, the DynoSim increases the valve acceleration rates to coincide with the lobe shapes that are commonly found on these cam grinds. See pages 53 in the User Guide for more information about lifter selection.

Question: Can I change rockerarm ratios with the DynoSim?

Answer: Yes. Simply use this formula to alter valve lift (the DynoSim will calculate the new valve motion throughout the lift curve):

                        New Ratio
New Lift = Old Lift x -------------
                        Old Ratio

When you have calculated the new valve lifts for the intake and exhaust valves, enter these numbers directly into the component-selection screen (make sure Auto Valve Lift is turned off).

Question: I found the published factory seat-to-seat valve timing for Pontiac engine that I am building. The IVC occurs at 112 degrees (ABDC). Something goes wrong when it enter the valve events into the DynoSim.

Answer There are so many ways that cam specs can be described for cataloging purposes that itís confusing for anyone trying to enter timing specs into an engine simulation program. Your Pontiac is a classic example of this lack of standards. The Pontiac cam listed in the factory manual is a hydraulic grind with seat-to-seat timing measured at 0.001-inch lifter rise. Because the cam is designed for long life and quite operation, it has shallow opening ramps. This is the reason for the large number of crank degrees between the opening and closing points. In fact, during the first 35 degrees of crank rotation, the lifter rises less than 0.010-inch. If this wasnít the case and the valve opened and closed at the specified timing points listed in the factory manual, the cam would have over 350-degrees duration, and itís unlikely the engine would even start! The DynoSim can use 0.004- or 0.006-inch valve rise, 0.007-open/0.010-close valve rise, or even 0.020-inch lifter rise for seat-to-seat timing. But the 0.001-inch lifter-rise figures published in your factory manual are useless for engine simulation purposes.

Question: My cam manufacturerís catalog does not list seat-to-seat valve-event timing. But it does list seat-to-seat intake and exhaust duration, lobe-center angle, and intake centerline. Can I calculate the valve-event timing from these figures?

Answer Yes. Use the Cam Math Calculator built into the DynoSim to calculate the intake and exhaust opening and closing points. Youíll need all of the following information:

1)  Intake Duration
2)  Exhaust Duration
3) Lobe-Center Angle (sometimes called lobe separation angle).
4) And the Intake Centerline Angle.
See the User Guide for more information on the Cam Math Calculator.

Question: I have been attempting to test camshafts from a listing in a catalog. I can find the duration and lobe center angle. The cam manufacturer wonít give me the seat-to-seat timing (they act like itís a trade secret). Can I use the available data to test their cams?

Answer: No. As stated in the previous answer, you also need the intake-center angle to relate cam lobe positions to TDC and, therefore, crank position. Freely providing seat-to-seat timing or any of the other cam specs used in the DynoSim poses no threat to any cam grinder. It takes a lot more than valve-event timing to manufacture a quality cam; full profiles of the lobes are needed to ensure mechanically and dynamically stable operation. Cam companies that refuse to provide potential customers with simple valve-event information for evaluation in programs like the DynoSim are simply living in the "dark ages." Our suggestion is to contact another cam manufacturer.


Question: The DynoSim displayed an error message "The DynoSim was unable to complete the simulation. A more balanced combination of components..." What went wrong?

Answer: The combination of components you have selected produced a calculation error in the simulation process. This is often caused by using restrictive induction flow on large-displacement engines, using a very short stroke, or by using radical cam timing on otherwise mild engines. Try reducing the EVO timing specs, increasing the induction flow, lengthening the stroke, selecting a cam with less duration, or reducing the compression ratio. A balanced group of components should not produce this error.

Question: The DynoSim Iterator takes several seconds to complete one cycle of a several-thousand run test. A full series takes way too long. Is there a problem with my computer or the software?

Answer: The DynoSim is a full 32-bit highly optimized program, however, it uses a powerful full-cycle simulation that performs millions of calculations for each point on the power curves, and this takes some time. Refer to pages 7 and 8 for more information on computation times for several computer systems.

Question: I have tried many different engine combinations using the same engine displacements and have noticed that several of the power curves begin at nearly the same horsepower and torque values at Simrpm. Why are they so similar at this engine speed?

Answer: Since the DynoSim uses a simulation technique that iterates toward an answer this is different from built-in Iterative Testing the first power point must be developed based on educated "guesses" about mass flow and other variables. The next point, at 2500rpm, is calculated from the starting point, plus the data obtained from the completed simulation, so accuracy is higher. By 3000rpm, the power points are based on simulation calculations with virtually no remaining influence from the initial estimations.

Question: When I run a simulation, part of the horsepower and torque graph doesn't appear on my screen. What can I do to correct the display?

Answer: Open the Graph Options menu (right-click on the graph) and select Auto Range for the Y1 or Y2 variable. See the User Guide for more information about graph scaling and plotting variables.

Question: While using the Iterator, II specified a 30-degree range of values for IVO cam timing with 5 degree steps. But the number of steps displayed is zero. Whatís the problem?

Answer: Always specify the lower (smaller) number in the left range box and the higher number in the right range box. The Iterator increments the left-box value with the step value until it reaches the right-box value.

If you havenít found an answer to your problem here, contact (ProRacing Sim Software provides technical service to registered users only. If you haven't already, register your software today). We will review your problem and return an answer to you as soon as possible.

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