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Lowering
Topic Started: Jan 15 2010, 10:20 PM (1,637 Views)
Coche Blanco
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Tell me then why companies lower cars 1 or 2 inches and do other various mods to add MPG?
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Bad Bent
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Facetious Educated Donkey

Here's an article on creating a front 'under tray.' http://autospeed.com/article
One statement; "One source of inspiration for this approach was the Mercedes-Benz SLR McLaren road car. As this diagram shows, the McLaren uses a flat undertray with rear diffusers."
With Slideshow.
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starscream5000
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Got 70 MPG?

Our cars are not smooth underneath if you've ever taken the time to look. There is parasitic drag on the underside of the car that can be reduced by lowering the car. Lowering will reduce the amont of air that can have a chance to flow under it, causing less drag. To further benefit from lowering, a complete underbody tray with a rear diffuser will significantly reduce the drag underneath the vehicle.
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bogs
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Duct tape heals all wounds

BB, that is 2 very excellant articles on aero. :thumb bud :) From the first one you posted, part of what interested me was the article mentioning the rake of the chassis, i.e. lower in the front / higher in the rear. I wonder if that wouldn't be just as effective as the skirting/damming/and possibly tubbing the underside? The article explained it better than I can, again thanks for the reading material :thumb
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Bad Bent
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Facetious Educated Donkey

You are welcome, bogs.

I have an image of a NASCAR car in my head. I believe the tail would be raking? I look at mine, being able to still get 51 mpg, and the air dam may effectively lower the front end, making the rear end higher (without doing any spring cutting), as you suggest. BUT good point, worthy of contemplation. :thumb



*Just an all points bulletin on aerodynamics for everyone: check your cars rear bumper for air flow. My '91 has stylish indented slots or a fake grille. I cut the plastic out so it is now long slots that allow air flow and reduce the parachute effect. The Wife's '96 already has an air flow through system.
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bogs
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Duct tape heals all wounds

Actually, I wasn't thinking so much of spring cutting, i.e. lowering the front, but more along the lines of rear end lifting to create the same rake. back in the day when I was a kid, one of the most common things we did was to fit larger width/diameter tires in the rear (kinda like james pro-gasser look). Of course, one of the things you come up against is rub, so you have 2 solutions, tub the rear end (we did that a LOT), or lift it via taller springs and / or air shocks.

We got much the same rake as listed in the article, so I would think the front was still squeezing off the air flow much as it shows there. (Of course, we weren't doing it for aero when gas was only 30-40 cents a gallon :lol )
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Bad Bent
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Facetious Educated Donkey

Good point. :)

Maybe the taller rear wheels would work... B-)
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bogs
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Duct tape heals all wounds

That under the nose tray article was also extremely intriguing, they are claiming a 5 mpg gain from that on the Prius. :hmm I wonder if a combo of those 2 would do anything :dunno
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Coche Blanco
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Raking a car forwards, increases frontal area and changes Cd. It can changes Cd for the better, or worse.

Option 1: Rake car and lower Cd enough to offset the increase in frontal area.
Option 2: Rake car and increase Cd and frontal area.
Option 3: (rare) Rake car and decrease both.
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