10-18-2009, 11:19 AM | #1 | ||
Drives: CTS/CAMARO Join Date: Jun 2009
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Calculating Ram Effect
Here is some info from some engineering sites.
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10-19-2009, 12:59 PM | #2 |
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I look at it from an airflow perspective (instead of pressure). Its a little less precise, but a lot easier to follow.
Find the flow rate of air the inlet would be collecting by multiplying its area by the speed of the car. Find the air consumption rate of the engine at WOT (displacement*RPM/2). If the car needs more air than is being forced in through the scoop there is no significant effect. For my Grand Am (which says Ram Air right on the fender) the twin openings are roughly 7.5"x3" which gives an area of 290 cm^2. At 60 mph that would give 46,700 L/min. Now, how much air does my engine need? My 3.4L makes its peak power @ 4900 rpm so it would require 8,200 L/min. There should be a rather significant ram air effect in my car. I have no clue how much extra power I would get from it but clearly more air could be forced into the engine than it would ever need. Contrast that with a 9"x1/2" mailslot opening feeding a 6.2L engine. That would give 9300 L/min at 60 mph but the engine needs over 18,000L/min of air at its power peak of 5900 rpm.
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10-19-2009, 01:11 PM | #3 | |
Drives: 2010 VR 2SS/RS A6 Join Date: Oct 2008
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No disrespect intended, but check out this link and then rethink your calculation using The fluid mechanics theory. The results may surprise you. http://www.camaro5.com/forums/showthread.php?t=48033
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10-19-2009, 01:49 PM | #4 | |
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__________________ Originally Posted by FbodFather My sister's dentist's brother's cousin's housekeeper's dog-breeder's nephew sells coffee filters to the company that provides coffee to General Motors...... ........and HE WOULD KNOW!!!!__________________ Camaro Fest sub-forum |
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10-19-2009, 02:39 PM | #5 | |
Drives: 2010 VR 2SS/RS A6 Join Date: Oct 2008
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WoW I didnt know Our northern brothers were so smart. (please hear the sarcasm in my voice)
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