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Visner Engine Development, LLC
609 Ottawa St.
Lowell, MI 49331
Phone: 616-897-9751
Fax: 616-897-9753
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News 2008
- September• Kurt Johnson qualifies #1 and finished 2nd at the Carolinas Nationals.
- August• Kurt Johnson wins the Lucas Oil Nationals at Brainerd, Minn
- June• Kurt Johnson wins the Torco Route 66 Nationals in Chicago
- May• Warren and Kurt Johnson qualifies #1 and #2 at the O'Reilly Thunder Valley Nationals at Bristol
- • Kurt Johnson wins the O'Reilly Midwest Nationals in Madison.
- March• Kurt Johnson qualifies #1 at the O'Reilly Spring Nationals in Houston
- News Archive
Technical Information
Technical Information
How much does it flow?
This has been the standard question for evaluating a cylinder head for years. Today, it is only one factor in the port design process. Big ports that flow a lot of air frequently do not run well. I often tell racers that all good running ports flow good, but not all good flowing ports run good.
The flowbench has been a valuable tool. When we were working with poorly designed ports, we made airflow gains that made the port more efficient. These gains made more power and we all got flowbench crazy. Eventually, we started to realize that the flowbench does not accurately simulate a running engine and to make ports better, we had to look at other factors.
A flowbench has only one dynamic action, the steady state airflow at a specified depression (usually 28 inches H2O). A running engine has multiple dynamic actions occurring simultaneously like piston movement, valve movement, intake flow, exhaust flow and pulse waves from multiple cylinders. This complicates the port design which needs to be tuned to the engine size, rpm range, and intended use of the application.
When evaluating cylinder heads for modern racing engines, airflow should be low on the list of important factors because as a professionally prepared port, they should all flow well. I recommend working with a cylinder head designer that has knowledge with the head requirements for your engine design and racing application.
