Rear vented hood pics, ready for molding :-)
Rear vented hood pics, ready for molding :-)
03-15-08, 10:28 AM
#7
My 7 is my girlfriend.
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About damn time man. Although I was expecting them a little later in the year. I guess that's one more thing to start saving for. One question though, wasn't the vent a little farther forward on the previous hoods?
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03-15-08, 08:34 PM
#10
Bill Hates
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Dimensions are the same as the old design. Bascally the only difference is the ridge around the vent has been deleted for a nicer profile.
03-15-08, 08:37 PM
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03-16-08, 07:11 PM
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It doesn't really matter about the ridge, any opening in an Rx7 hood will vent hot air (that isn't forward facing of course) take a look at the scoops on a GT40, no ridges there...
03-16-08, 07:31 PM
#22
But there are air ducts that channel air directly to the ducts. Have you done any pressure testing at speed with the FB hood? Did you know that if you prop your hood in the back it acts as induction and not a vent? You need to make sure that the air pressure in the exact spot that the vent is at is higher than the air pressure passing over the car as it travels. Or the vent will not be a vent at all it will be a intake and all that extra air going under the hood has nowhere to go bu under the car causing lift. I'd hate to sell a product that killed some ricer kid because he thought his hood was venting air instead of it actually causing lift. If there isn't enough under hood pressure to over come atmospheric pressure and all the other pressure as the air passes over the car then you need a lip to cause the pressure drop and make the hood actually vent under hood air. You also have to remember the GT40 has hundreds of millions of dollars of development that went into that car, and I'm sure some of it went into the areo dynamics fo the car. And I'm sure the GT40 has spent plenty of time in a wind tunnel making sure it's vents work.
03-16-08, 07:38 PM
#23
djessence
I'd hate to sell a product that killed some ricer kid because he thought his hood was venting air instead of it actually causing lift.
While i agree on both fronts, I think the venting/lift will provide cooling no matter where the air is goin. Its goin somewhere. The amount of lift caused (if any) is not going to be THAT significant.
As well, yes the GT40 did have millions spent in R&D when it was made. But it was also a purpose built high stress racing car. The slight change in aerodynamics on our cars at the speeds they will be capable of is not going to make a huge amount of difference. For the cars like the GT40, the location of that venting and how deep it is etc. makes the difference of 0.X of a second a lap at le mans. Not significant by itself.
I am glad to see Fibremaz still developing different products for the ever dying breed of te 1st gen
Last edited by djessence; 03-16-08 at 07:45 PM.
03-16-08, 07:49 PM
#24
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When I had a vented hood on my car after a drive you could feel that the mesh/vent area was very warm and surrounding areas were not which to me is an indication that it's venting hot air. I would love to get one into a wind tunnel but that's mega $$$ and not readily available where I live. When I get a vented hood back on my car I will try and get some underhood temp readings with flat hood and vented hood to show that it works
03-16-08, 07:56 PM
#25
djessence
When in doubt use the sticky page markers (colored tops, tape bottoms), go for a drive and observe their behavior. Cheap way of wind tunnel, works best on non windy days. Videoing it helps too. Its what we used when were designing our solar car project in the intial stages because we were only allowed x amount of hours in the wind tunnel.
EDIT: You place them strategically on some form of pattern (depending on where you wanna test). Takes a bit to figure out and you dont get the advantage of the smoke screen to observe but it does give a ROUGH idea.
If you observe a wind tunnel test, they use a much more expensive piece of tape thing (cant remember name). Placing them backwards and forwards. Staying flat is good aerodynamics, up or flapping is turbulent air (obviously).
EDIT: You place them strategically on some form of pattern (depending on where you wanna test). Takes a bit to figure out and you dont get the advantage of the smoke screen to observe but it does give a ROUGH idea.
If you observe a wind tunnel test, they use a much more expensive piece of tape thing (cant remember name). Placing them backwards and forwards. Staying flat is good aerodynamics, up or flapping is turbulent air (obviously).