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Old 07-07-2010, 01:50 AM   #1 (permalink)
iplaysdrums
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Join Date: May 2010
Location: Duluth, MN
Posts: 30

Tony - '15 Honda Fit EX
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2004 MINI Cooper S - Improving Aerodynamics

I've never posted here before, so this will likely seem totally out of left field, but I've been lurking for several months, and I finally started modding a few weeks ago.

The car is a 2004 MINI Cooper S (R53 - Supercharged) in British Racing Green, and for the most part it's completely stock. I replaced the ignition coil with an MSD Blaster, and I upgraded the plugs and wires at the same time. Aside from that, I've installed a PLX Kiwi MPG (about half the price of a ScanGauge), but I haven't yet gotten it calibrated properly, so the trip average mpg readout stays around 7.8 mpg, regardless of when I reset it and how I drive.

I removed the exhaust tips because they add weight (and possibly a little bit of drag) and serve no non-cosmetic purpose, and I replaced the long, wiry antenna with a stubby, rigid one. I also removed the rear spoiler, as the car is FWD and will likely never see more than 100mph (and that's only in case of emergency), so the downforce it might or might not actually provide at those speeds is pretty much irrelevant.

I started with the more radical mods a couple of days ago, and since then have achieved rough grille blocks for the upper and lower grilles (I'm leaving the hood [bonnet] scoop open), as well as extending the factory airdam a couple of inches lower (I decided on this instead of a full belly pan because it's way easier and AndrewJ went with the airdam instead of the belly pan and had great results). Anyway, I did all that with black coroplast.

I'm really terrible at fabrication, so none of it looks good at all, and I'm also very undisciplined about testing, so I'm sure I'm going to drive the hardcore aeromodders nuts. Nevertheless, I'm trying, and that has to get me a certain amount of credit.

I have a few more radical-esque mods planned, and ideas for a couple more:

The most significant area of drag for most hatchbacks seems to be the rear, which just kind of falls off, leaving a huge turbulent wake. While a full boat-tail is the best solution, this car is hopefully going to be a daily driver for another 2-3 decades, so I don't want to do anything TOO radical, and I definitely want it all to be pretty much reversible (I have a few screw holes that are permanent, but you'd have to look hard to find them).

That said, I'm planning a removable boat tail of some sort based around a strap-mounted bike rack (most likely a Yakima Megajoe). When we moved to Oregon, we drove from southern Illinois with the car completely packed, with a Schwinn cruiser on the back of the car. Those cruisers are massive bikes, and it stuck out on both sides of the car, as well as over the top, so the wind assault was brutal for a few thousand miles. Every night, we took the bike off and I checked all the straps, and none of them had loosened at all, which leads me to believe this thing is crazy sturdy, so it'll be ideal for mounting the tail.

Rear wheel skirts/fairings should bring measurable gains, considering the wheels and tires protrude past the wheel arches, causing all sorts of turbulence. I'm planning on mounting them directly to the body after removing the arch covers, and I'm thinking since there's hardly any bumper at all behind those wheels, I may make the fairings just a bit longer and create a slightly more permanent partial boat tail.

If you've ever looked at the front of a MINI, particularly a Cooper S, with its larger wheels, you've probably noticed that the wheels and tires poke out of the wheel arches just like they do on the back. If I can somehow extend the bumper to cover this, that combined with the rear wheel skirts should keep flow attached on the sides of the car significantly better than stock. The easiest way to do this might actually be the hardest, but I'm thinking if I have a large, curved piece to cover the entire front bumper, it can extend past the wheels, while serving as as an airdam, grille block, and front wheel fairing. Being that my fabrication skills are virtually none, I don't see this happening unless someone is willing to give me MAJOR hands-on help.

So, these are my plans. I'll have pics of the mods up once I've made enough posts, but pm me in the meantime if you want to check them out.


Last edited by iplaysdrums; 07-07-2010 at 02:10 AM..
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