which headlight would you prefer?
I figure since they're a big, front facing flat surface that acts slightly as a scoop as well, they probably drag terribly. Granted, it might only make a difference of a quarter second from 0-100mph, but definitely it'll hurt mileage, too.
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Joined: Feb 2006
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From: USA
Great idea, except that you don't know the total drag force on the car and the air flow against the paddles is not equivalent to the air flow at the lights.
In other words your test fails to come up with even an order of magnitude for calculations and can't even conclusively state whether there would be a net increase in drag. It's still possible (though highly improbable) that the front fascia design was made with the lights in mind such that the total coefficient of drag for the vehicle has a statisticly insignificant variation between the lights being up and down.
I don't need a Physics 101 lesson here, I was looking for some meaningful answer.
In other words your test fails to come up with even an order of magnitude for calculations and can't even conclusively state whether there would be a net increase in drag. It's still possible (though highly improbable) that the front fascia design was made with the lights in mind such that the total coefficient of drag for the vehicle has a statisticly insignificant variation between the lights being up and down.
I don't need a Physics 101 lesson here, I was looking for some meaningful answer.
Senior Member
Joined: Apr 2006
Posts: 429
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From: Northern Virginia
Pretty sure it doesn't matter too mcuh either way, pretty sure you're car still has to displace the amount of air regardless whether it's up or down (unless you had some sort of magicial car that totally disappears from space when your headlights aren't up). The only difference between the two is whether you're running in or cutting through the air. Quite frankly I highly doubt it's big enough of a difference to matter.
Up
Up
I like pop up better.
Best thing about it was when I made the lights pop up one at a time in my 240, it looked as if it was winking LOL
I did it in a row and one light goes up, one light goes down, and so on.
Best thing about it was when I made the lights pop up one at a time in my 240, it looked as if it was winking LOL
I did it in a row and one light goes up, one light goes down, and so on.
I hit 144 on a slight(very slight) down grade in my first N/A at night in June. Flip up for sure, no matter how un-aerodynamic they are. But I agree with MaczPayne the Knightsport lights are killers.
Too many engineers in here 
Yes, drag will eat some speed and reduce fuel efficiency at highway speeds....crap, now I'm doing it too!
Anyways, I like the look of the light covers reflecting at night back at the driver and how they move with you when you turn - know what I mean? It's part of the charm. Reminds me sort of like the old school Ferrari's looking down the hood.
Yes, drag will eat some speed and reduce fuel efficiency at highway speeds....crap, now I'm doing it too!
Anyways, I like the look of the light covers reflecting at night back at the driver and how they move with you when you turn - know what I mean? It's part of the charm. Reminds me sort of like the old school Ferrari's looking down the hood.
I'd say flip-ups are more stylish and fun- they simply don't make cars with pop-up lights anymore, which is a pity imo.
Then again, the lower profile lights provide better aero, are less mechanically complex, and more ideal from a performance standpoint. (Yes, I'm a engineer too) Does anybody know the weight difference between the stock pop-ups and a set of low-profile lights? Or better yet, where to find a set of them now?
Then again, the lower profile lights provide better aero, are less mechanically complex, and more ideal from a performance standpoint. (Yes, I'm a engineer too) Does anybody know the weight difference between the stock pop-ups and a set of low-profile lights? Or better yet, where to find a set of them now?
Senior Member
Joined: Apr 2006
Posts: 353
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From: San Diego, Socal
I know that. I meant at what point is it a significant term in the drag equation. If at 10 MPH it's 0.0001% of your drag and at 100 MPH it's 0.01% of your drag it's definitely insignificant. If the numbers are 1% and 30% however, that's a meaningful difference.
More precisely:
What is the total drivetrain drag on the vehicle?
What is the airspeed drag with the lights down at 30 mph? 60 mph? 90 mph? 120 mph?
What is the airspeed drag with the lights up at 30, 60, 90 and 120 mph?
Why do I keep starting to type "dragon" whenever I type "drag"?
Why do I do the same for "ration" and "ratio"?
Funny thing is, the most aerodynamic production vehicle (which was neither the Element nor the FD) looked like a rolling brick.
More precisely:
What is the total drivetrain drag on the vehicle?
What is the airspeed drag with the lights down at 30 mph? 60 mph? 90 mph? 120 mph?
What is the airspeed drag with the lights up at 30, 60, 90 and 120 mph?
Why do I keep starting to type "dragon" whenever I type "drag"?
Why do I do the same for "ration" and "ratio"?
Funny thing is, the most aerodynamic production vehicle (which was neither the Element nor the FD) looked like a rolling brick.
Its always the same ratio, because its effect on the drag coefficient remains pretty much constant.
I will say that it will knock a good 10 mph off your top speed...which I know from experience.
\Aerospace engineering student here
--Alex
Last edited by raptor22; Aug 18, 2007 at 01:16 PM.
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