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Old 07-21-2010, 05:05 PM   #15 (permalink)
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It all depends

Quote:
Originally Posted by ChazInMT View Post
Am I the only one who wonders why the rear spoiler??

It seems like that would be adding drag. You may want to give consideration to losing that. I have never seen an ideal aero template with a spoiler on it. If it is creating downforce, it is creating drag, and if you keep your speed under 150 MPH, control shouldn't be an issue.

I could understand if you had some huge awful curving back end on a car (Think VW Bug, Audi TT Coupe) why a spoiler would help by detaching flow at a more beneficial place in the slipstream, but the Altima appears to have a nice thing going without the extra bump.

It does look cool, gotta give you that, and it probably isn't costing you a lot. Any guru's want to chime in on how I may be mistaken about this, I'd love to hear it. I have given this a lot of thought since driving a rented 09 Corolla S last fall for a month with a wing thing and wondering if it wasn't a drag load.
Chaz, Some deck spoilers may hurt, some may help and some may have no significant effect on fuel mileage. Post #8 indicates no real difference for this Altima. How could a deck spoiler help?? The Salt Flats racing Ford Fusion used an extension off the back deck to make the car's shape come closer to fitting the "aerodynamic template" found on this site. The half teardrop (Ultimate Aerodymnamic Car) is optimum but it can be stepped too. It is a compromise but this is why a pick-up has less drag with the tailgate up than down, even less drag with a tonneau, and even less with an aero Kammback.

Quote:
Originally Posted by superchow View Post
I would like to offer a different perspective from personal experience. While I am not advocating hyperinflating tires, pressures at or below the max. sidewall has always been safe for me. I got 60,000 miles out of my previous set before the tread on the edges was more worn than the center of the tread.
This has been my experience as well. I have run tires at or above sidewall pressure since I began racing autocross in the '80s with no problems. I will admit that there may be slightly less traction on hard acceleration but better cornering traction because the tire doesn't roll onto its outside edges as easily. Hypermilers may take corners at higher speeds to conserve momentum but don't typically do smokey burnouts. I have seen some treadwear in the middle but still usually get 60-80,000 miles from a set of tires. You may notice a slighter harsher ride and much improved coasting.
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Quote:
Originally Posted by freebeard View Post
The power needed to push an object through a fluid increases as the cube of the velocity. Mechanical friction increases as the square, so increasing speed requires progressively more power.
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