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The Air Intake system on the MCS Introduction Getting enough fresh, cold air into the cylinders is a challenge on normally aspirated (NA) cars, but even harder on forced air vehicles that use a turbocharger or a supercharger, since these devices raise the air temperature as they raise the air pressure. Consequently you often see intercoolers (sometimes called aftercoolers) and big scoops. Getting more cold air into the MINI Cooper S requires a few standard mods, and a few innovations, which I have documented here. The standard mods include a Cold Air Intake, which replaces the stock air filter box and panel filter with an airbox that seals against the bonnet, or has a sealed top, and opens to the rear cowl to get air from the cowl opening in front of the windshield, driver's side. These CAIs also receive fresh air from the front of the car via a duct that runs from the radiator shrowd to an opening at the bottom front of the airbox. That's it for the source of air to the air filter. CAIs also use high flow, less restrictive air filters, which tend to increase the noise levels, especially if the cowl divider is removed, as is the case with the Alta CAI. Another pretty standard mod is a bigger scoop, and there are only a few available. M7 makes a Ram Intake, an asymetric scoop for the DFIC (direct flow intercooler) and an Extreme scoop. Palo Uber also makes a larger scoop which I have never tried. Larger scoops have bigger capture areas and usually bigger openings to the IC. To mate the scoop to the IC you need a diverter. The stock diverter is pretty lame, the Alta one is pretty good and works well for TMICs (top mounted, or downdraft, intercoolers) and the M7 DFIC comes with its own diverter. The diverter stops airloss around the IC, especially in front where the radiator hose and intake manifold are, and some try to direct air to the IC cooling fins. Currently there are no exhaust flow diverters, which would try to manage the flow of heated air exiting the IC. I'll work backwards in the following presentation, from the current DFIC setup, all the way back to the OEM TMIC.
Improving air flow through the DFIC (Jan 21, 2007) The DFIC is a plate and fin radiator, in which the air flows
through the IC from left to right across lots of thin Aluminium fins.
These fins transfer the heat generated by the supercharger (SC) to large flat
horizontal plates, which are joined by sets of fins that run from front to back,
through which fresh air flows, transferring and exhausting the hot air to the
back of the engine bay. There's not much can be done internally to improve
flow, heat transfer and pressure loss, but quite a bit can be done externally in
the following areas: More fresh air can be obtained with a bigger scoop. I have modified a Ram Intake scoop with a larger opening shaped more closely to the front of the DFIC, so it is deeper and wider at the left side than a stock DFIC scoop. Since the IC sits off center to the left/passenger side, there is some scoop frontal area that can either be directed to the IC, or redirected elsewhere, as I have done with my FAD (fresh air diverter--more below.) A new BIGGER scoop and FAD (fresh air diverter) A new, bigger and dual purpose hood scoop with a fresh air diverter from the scoop to the airbox. Note the vertical splitter that sends air left to the IC and right to the airbox.
The FAD is connected to a duct that delivers air to the top of the airbox, where it is sealed against the bonnet. A thermally insulated duct that dumps air directly into the sealed Alta air box. I am now on version 2.0.
I have conducted tests of the effectiveness of the FAD, and compared to directing air to the IC like the M7 DFIC scoop does, the FAD produces approximately 2-3F reduction in IC-out temperatures. At contant highway speeds, the airbox temperatures are consistently 1-2F below ambient, at least in winter here in Albuquerque. Proof that the FAD is diverting air to the airbox can be seen in this photo showing the dirt on the Alta airfilter.
Better airflow through the IC can be obtained by making the flat face of the plates a little more aerodynamic, as well as the exits. Such as these additions I fabricated:
Above front, and below, rear:
The fact that the plates are so big on the DFIC means they attract a lot of heat, which is being generated by the SC, the DFIC itself, and the engine which sits below it. The radiator also sits in front of, but below, the IC. The DFIC has ceramic coating on its underside. The next stage: getting the air out. Below is a sketch of an integrated scoop that has an intake like the Ram Intake, but with a much larger mouth, and an exit scoop with louvers. The engine is visible beneath so see how the scoop lines up with the intercooler and the shock tower brace.
Here's a side view:
These are just ideas. No one has made such a scoop for sale (M7 has a JS prototype), but some on NAM have cut vents and louvers in their bonnets to exhaust engine bay heat. None are specifically designed to increase flow through the DFIC.
Air Flow Management Controlling the airflow through the engine bay is very important. Getting air through the IC is clearly paramount, but getting air to the airbox and getting cold air to parts that would benefit from being colder is also critical. Here is my version of PARTSMAN's (Joaquin) intake manifold diverter, with radiator hose shield.
This is it finalized and painted:
and this is how much of the shroud has been removed:
Here's what it looks like with the Aerogel blanket installed between SC and intake manifold
I have tried lots of scoops, starting, of course, with the original one on the car. Here's a comparison of hood scoops: Original MCS scoop
and finally (with the FAD added)
Some History Before the DFIC, I had the stock IC, with various diverters and scoops. These are included in the photo below.
Above are the parts of the Cold Air saga that are now history, including (from right to left) the modified Alta diverter, the DFIC diverters: both mine and M7s, the OEM scoop, the M7 Ram Intake in carbon fiber, and the M7 DFIC scoop, both the last scoops designed by Joel (JS) on NAM. Earlier incarnations of the M7 Direct Flow Intercooler (DFIC) (Installed 8/18/06) I got my DFIC from Way Motor Works up at the MINI in the Mountains gathering. It's one of those pieces that you should not handle unless you want to buy it! I have the M7 Ram Intake in carbon fiber and did not want to lose it, so I fabricated a diverter for the DFIC that uses the entire scoop width rather than the new asymetric scoop that comes with the DFIC.
(Undertaken 2/21/06) This scoop was designed by two NAM guys, Sid (MSFITOY) and Joel (JS) and produced by M7 Performance in California. It took a while to get to
market, but it's finally here, and mine is about number 10 or 11. It's designed to fit into the stock opening in the bonnet, but cannot be used with the stock
diverter without modification, as the hole is clearly larger: The Intake does not come with instructions, but there's enough posts on NAM to get you going. The scoop fits very well, but requires a little modification to work efficiently with any diverter, stock or otherwise. If you choose to use the stock diverter (which is fitted to the underside of the bonnet,) you must remove material so that it ends up looking like the photo below:
I have installed the aftermarket Alta diverter which offers more thermal transfer (being steel rather than plastic like the OEM IC cover) and better collection and sealing of the air coming in the scoop. There's still leakage to the sides with the Alta as is, so I modified it to better scoop all the air coming in via the Ram Intake. I added a skirt to the front of the diverter to prevent air "leaking" in front of the IC, and extended the side seals all the way to the Ram Intake. Here's the modified front skirt:
Below is a sketch of the skirt modification.
Here are some photo composites I made to show how the diverter and the scoop fit together: In profile -
and from the front -
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