The main program screen allows you to select engine components, dimensions, and specificat
While the program provides a selection of generic head choices, choosing Custom Port
With pistons other than pure flat-tops, the Compression Ratio Calculator requires ei
The Cam Math Calculator allows direct cam data entry. It also simplifies changing lobe-cen
The magic of computers now lets anyone with a home computer build and test virtual engines in minutes. One of the best-selling programs in the budding field of engine-simulation programs is the Desktop Dyno series from Motion Performance and Mr. Gasket. In the March 01 issue of Car Craft, we reviewed Motions totally redesigned, Windows-based DragStrip 2000 drag-racing simulation program. We were impressed by its ease of use and accuracy in simulating known real-world vehicle combinationsso we couldnt wait for the opportunity to try out the new, improved Dyno 2000 advanced engine-building simulation program for Windows 95/98/ME/NT/2000.
Dyno 2000 links closely with Drag-Strip 2000. The DragStrip program allows you to import engine files from Dyno 2000 and see how well a car with that engine would do at the drags. Both programs look, feel, and behave like a standard Windows program.
Dyno 2000 is designed for use by people who have a wide range of engine building expertise. Many fields support both specific, direct data entry, orif you dont have all the numberstheres also an extensive library of predefined entries. An extra CD-ROM is included with an entire library of aftermarket cam manufacturers specs.
The program lets the user test virtually any normally aspirated, forced-induction, or nitrous-equipped engine. Its virtual dyno operates in a 500-rpm step-test mode increment from 2,000-11,000 rpm, and it corrects horsepower and torque data to 68-degrees F, zero humidity, and 29.92-in/Hg atmospheric pressure. Unfortunately, this is a different correction factor and testing regime than most actual dyno shops use. The user cannot alter the programs test mode.
Another drawback is that Dyno 2000 doesnt allow the user to enter specific design characteristics for intake manifolds (plenum volume and runner dimensions) or exhaust system design (header primary tube and collector dimensions, plus exhaust muffler flow capability). The induction and exhaust systems are key ingredients in determining the engines output and also the rpm level at which peak power and torque occurs.
For example, most of us know from real-world experience thateven though both are generically classified as a dual-plane intakethere is a significant difference between a standard Edelbrock Performer intake and the high-rise RPM Air Gap. But the program lumps all dual-planes together.
Similarly, you can choose between small-tube and large-tube headers, with or without mufflers. The programs user manual says you should select small headers if your primary tubes measure 95-105 percent of the exhaust-valve diameter; tubes that measure 120-140 percent of the exhaust-valve diameter are large tube headers. But Murphys Law says that the tube/valve size ratio usually ends up falling somewhere in between.
Selecting from the generic cam types can also lead to inaccurate results, but fortunately the program allows direct cam data input. We obtained more accurate results by using seat (or advertised) timing figures in lieu of 0.050-inch tappet-lift numbers. The program makes no provisions for connecting rod length (the programs authors dont believe it has a significant effect), nor how lightweight reciprocating and valvetrain components can alter an engines rpm band and frictional power losses. However, the program does provide three built-in calculators for cam timing, cylinder-head airflow numbers, and compression ratio calculations. The airflow calculator can convert any measured airflow and pressure drop to any other pressure drop and equivalent flow.
Because of the programs limitations, we had to fudge the input component selection to get close to real-world peak power numbers on two test case engines (see sidebars). Even so, torque production could not be accurately modeled.
One cool feature sets this program apart from other consumer-level engine sims: Taking full advantage of todays powerful processors, the iterative testing function allows the computer to evaluate hundreds, thousands, or (if your computer can handle the pressure) even millions of variations, then display the 10 best combinations. With its unique iterative function, we believe this program is most useful for homing in on overall trends or the effects of changes of an existing known engine combo rather than predicting exact real-world output. While this program is a definite upgrade over its clunky DOS-based predecessor, we feel that Dyno 2000 is still a work in progressand have to give it a two on a scale of five. Its available for $49.95 through Mr. Gasket.
Motion Software Inc.