Synlubes Posted April 4, 2003 Share Posted April 4, 2003 So I was looking at the new hood vents John Washington is making(Very Nice), and read this. . . "From about ten miles an hour and up, the flow actually reverses due to a high pressure area that forms at the base of the windshield (which is why the cockpit ventilation intakes were put there). This provides a stream of cool, outside air flowing down across all the vital engine parts previously mentioned, and out through the bottom of the engine bay (with assistance from high velocity, low pressure airflow under the car...Bernoulli effect)." So, does air get sucked in a cowl induction hood as well ? So does the same effect happen with the standard 280Z hood vents ? Does the air get sucked in when the MPH`s increase ? What about the air entering the engine compartment from the radiator opening at speed, does this not counteract the air trying to come in from the hood vents ? I have a vented 280Z hood and DON`T want air to be sucked in at speed but for the air to be sucked OUT of the engine compartment at speed . What would need to done to make this happen ? Would some kind of little lip in front of the vents change the way the air flows over the(stock)vents. I also made some inspection lid vents, is air being sucked in at these vents also ? Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted April 4, 2003 Share Posted April 4, 2003 You could answer this for yourself if you taped little telltales of yarn on your hood and vents, and watched what they do at speed. Quote Link to comment Share on other sites More sharing options...
Synlubes Posted April 4, 2003 Author Share Posted April 4, 2003 Yes, you are right about watching what happens but from what John`s artical says " From about ten miles an hour and up, the flow actually reverses due to a high pressure area that forms at the base of the windshield " So, that doesn`t answer my ?`s. Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted April 4, 2003 Share Posted April 4, 2003 The front of the windsheild is always going to be a high pressure area. Cowl induction hoods use this to feed air in, not out. The best place for a air vent is further forward just behind the radiator. This is a low pressure area on the s30 and it will suck air out. Dave's suggestion of putting tell tails on the hood is a good one. Where they start to lift is where you want to put the vents. We have had some mighty fine discusions on this in the past, Might pay to do a search as well. Cheers Douglas Quote Link to comment Share on other sites More sharing options...
blueovalz Posted April 5, 2003 Share Posted April 5, 2003 I did the tuft experiment quite a while back and the higher pressure (and more chaotic air flow) at the base of the windshield diminishes substantially by the time you get about 1 foot forward of the windshield, which appears to be where your vents are located. These vents I have on my hood (which are located in a similar position) do an excellent job of pulling out hot air from under the hood. Quote Link to comment Share on other sites More sharing options...
S30Z Bushido Posted April 5, 2003 Share Posted April 5, 2003 holy crap terry. that is a serious hood! very nice, same goes for the one up top. Quote Link to comment Share on other sites More sharing options...
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