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Spoiler or Air Dam


Hunter260Z

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Hybridz did a windtunnel test of the S30. There were only two air dams tested, BRE and MSA type3. Data shows that the MSA type3 was twice as effective at reducing lift (no downforce in Z cars, unless highly modified) compared to the BRE. I have a feeling that the MSA type1 is also more effective than the BRE.

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I have the spook on my car, and I'm certain that a modern air dam could be more effective at high speed. That said, the improvement that my spook gave over stock was huge. And since I rarely drive much faster than 75 MPH in mine, I'm willing to trade some aero efficiency for appearance. I prefer the looks of the spook.

Edited by Arne
typo
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Looking at the wind tunnel results, the two weren't tested back to back so as to make a direct comparison, but if you look at the first test of both, in test #9 of the BRE spoiler you have 203 lbs of lift in the front, and in test number 16 the original test of the Type III you have 195 lbs of lift in front. Not a real significant difference.

The real difference came when they blocked off the gigantic opening in the front of the grill and the Type III, and that's not exactly an apples to apples comparison. Based on the idea that blocking more of the air from going under the car is going to reduce lift, I would say that a solid airdam that comes closer to the ground and doesn't have a big hole in it would likely do better than the BRE (too high off the ground) or the Type III (big hole) before modifications.

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This is my BRE Mk 1 or Series 1 Spook that was already installed by the dealer when I bought my car 03/31/71. It has been fully re-habbed and will be back on the car soon.

post-22303-14150815744869_thumb.jpg.

It was the first design from BRE and used in 1970 competition only, to the best of my knowledge. Check the BRE archive pictures (link below) to see the 1970 car and the change on their 1971 cars to the design more commonly associated with the early BRE Spook. I suspect the first design did not provide adequate downforce, hence the redesign for 1971.

http://www.bre2.net/mm5/merchant.mvc?Screen=CTGY&Store_Code=B&Category_Code=brearchivephotos240zs

Jim

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There was a report by some NasTcar teams that by simply covering the grille with duct tape, they had a noticeable improvement in handling and speed, but at the cost of less cooling.

I agree with Leon, that the air dams don't add to downforce, but only block air from going under the car, reducing lift, and that the spook spoiler is more of a way to direct air to the radiator than to make any down force.

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Modern cars seem to throw a so-called splitter below the airdam that runs flat back to the front axle (or to a rear difuser if the car has underside panels).

The front of the splitter seems to protrude infront to the dam and catch downward spillage that creates down force.

A rake in the car can also create downforce.

http://www.modified.com/tech/0610sccp_automotive_aerodynamics_part_2/photo_11.html

Here is a nice read: http://www.rapid-racer.com/aerodynamic-upgrades.php

Edited by Blue
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Funny how neither looks like mine or some of most common I've seen. I would love to see more styles compaired in wind tunnel w/ just air dams & no spoilers, side skirts, etc. I've considered the splitter on my Miata but looks a bit too trendish or something.

post-23475-14150815752175_thumb.jpg

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