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Old 12-27-2012, 01:32 PM   #11 (permalink)
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good point maybe conventional wisdom that lower is better is not necessarily correct

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Old 12-27-2012, 01:50 PM   #12 (permalink)
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Many new cars have active suspensions that lower the vehicle for better highway fuel economy. There's another thread on the topic here: Does reducing ground clearance REALLY reduce drag?

I installed 1" lowering springs on mine mainly for the handling benefits (since the stock springs are far too soft and body roll was VERY prominent), as well as the slight reduction in frontal area.
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Old 12-27-2012, 06:17 PM   #13 (permalink)
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So if this is true should I remove the front spoiler on the front of the Ranger and add a smooth rolled back one instead?
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Old 12-27-2012, 06:36 PM   #14 (permalink)
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lowering

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Originally Posted by wungun View Post
Thinking about lowering my car...For looks, handling and aero...
What goes on in a lowered car that makes the aero more efficient?
Lowering improves the fineness ratio (length/height)of the car which is extremely important to drag.
The lowest drag concepts all use active suspension to lower and rake the body for maximum drag reduction for highway-only driving.For in town use the car raises to SAE minimum clearances.
Hucho spends a bit of time in his books discussing this very thing.
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Old 12-27-2012, 09:24 PM   #15 (permalink)
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I suppose with these cars they have to be raised up in order to fit proper sized tires underneath?
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Old 12-28-2012, 02:29 PM   #16 (permalink)
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I lowered my pickup 4 inches and garnered a solid 1.0 MPG improvement (measured over at least 1500 miles of the same circuit same time of the year).

No other changes.

I'm sold on the idea.
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Old 12-28-2012, 02:30 PM   #17 (permalink)
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Remember what aerodynamic drag really is... its the amount of force on the vehicle from you accelerating the air in the direction of the vehicle. Drag is dependent on two things: 1. how much air & 2. how fast you accelerate that air forward (in the direction of the vehicle).

Want to REDUCE drag? Reduce the amount of air impacted (smaller frontal profile) or lessen the acceleration of the air (smooth the flow over the length of the vehicle).

**Don't forget you are pushing the air in the front (high hanging fruit), and sucking the air in the back (lower hanging fruit)**

HOW THIS APPLIES:
The lessen the amount of air that you have being pulled forward by the protrusions under the car by reducing the gap between the car and the ground. This will reduce the amount of air available to be accelerated. It will probably have the same acceleration, but less air means less drag.

Other aerodynamicists chime in...

Ryan

Last edited by ryannoe; 12-28-2012 at 02:49 PM.. Reason: Poor flow (pun intended) ... tried to rewrite for ease of reading.
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Old 12-28-2012, 05:27 PM   #18 (permalink)
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raised

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Originally Posted by chrisgerman1983 View Post
I suppose with these cars they have to be raised up in order to fit proper sized tires underneath?
Yes,they're essentially a laminar wing profile and so thin they hardly contain the driver and mechanicals.And rulebook requirements for wheels/tires dictate the tires you see which are integrated into the body as best they can.
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Old 12-28-2012, 05:41 PM   #19 (permalink)
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drag

Quote:
Originally Posted by ryannoe View Post
Remember what aerodynamic drag really is... its the amount of force on the vehicle from you accelerating the air in the direction of the vehicle. Drag is dependent on two things: 1. how much air & 2. how fast you accelerate that air forward (in the direction of the vehicle).

Want to REDUCE drag? Reduce the amount of air impacted (smaller frontal profile) or lessen the acceleration of the air (smooth the flow over the length of the vehicle).

**Don't forget you are pushing the air in the front (high hanging fruit), and sucking the air in the back (lower hanging fruit)**

HOW THIS APPLIES:
The lessen the amount of air that you have being pulled forward by the protrusions under the car by reducing the gap between the car and the ground. This will reduce the amount of air available to be accelerated. It will probably have the same acceleration, but less air means less drag.

Other aerodynamicists chime in...

Ryan
The ph.Ds are going to say that the drag that we're interested in,is caused by flow separation and the static pressure differential between the forward stagnation point and the turbulent wake which it causes.
Hucho will say that the entire premise of streamlining is to reduce or eliminate the wake.
Less air is less drag.Drag varies arithmetically as a function of projected frontal area,all else being equal.If you reduce the Af by 50%,you've just cut drag by 50%.
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Old 12-28-2012, 08:12 PM   #20 (permalink)
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I lowered a 1978 Mercury Zepher 1" and saw no difference in fuel mileage and experienced all the annoying scraping and bottoming problems described by others here. I raised a 1986 Ford E350 diesel van 2" and included about 400 lbs of fulltime 4wd transfercase and front drive axle and only lowered the 55mph fuel mileage 2mpg from 24mpg(imp) to 22mpg(imp). Raising the van another inch had no measurable effect on fuel mileage.

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