SuperFlow AutoDyn, Operator'S Manual

Page: 206 / 208

Fundamental Concepts to Obtaining Superior Repeatability
Volume 3, 9/10/04
Appendix B - Page 213
Appendix B
Fundamental Concepts to Obtaining
Superior Repeatability
The following concepts were originally presented by Jim McKenzie of Hendrick Engines
Dynamometer Labs during the 1998 AETC conference. These are intended as guidelines for using
an engine dyno and obtaining maximum repeatability in your results. Following these guidelines
can result in +/- 0.1% repeatability. We've added additional info and hope this provides you with
the necessary guidelines to get the most from your SuperFlow product.
B.1 The Dyno Cell
• Air flow across the engine is a must. It must be sufficient to evacuate the test cell at
least 8 to 10 times per minute. Look for 1-1.75" water pressure drop in your test cell.
• Engine intake air should be sealed off from the environment inside the test cell. The
engine should draw its air from the shop if possible, or use outside shop air.
Additionally, you may add a fan to purge air in the plenum.
• Use some type of exhaust system and keep it sealed as well as possible. Many times
you will be working in the test cell with the engine running. Hazardous fumes will be
present unless you use some type of exhaust. Also, consider noise abatement
requirements for your area and use mufflers where required. Critical grade industrial
mufflers are a good choice. You also want little or no back pressure in your exhaust
system.
• Make sure your water system is adequate for your testing needs. You will use
approximately 10 gallons per minute for every 100 horsepower (5-6 gpm if you are not
running a cooling tower). To rapidly warm up engines, a separate pre-heated water
system can be employed, but it is recommended to use the dyno water system for
engine cooling. Pressurized cooling towers will increase repeatability and will allow
testing of the engine under more realistic conditions.