Did a search but couldn't seem to find the post I thought I had seen so...

How do you remove the grille from the scoop on the MCS '07 so I can Dremel out the holes that are blocked (about half of them)?

Would this be a bad idea? A good idea? Would too much water get in in the rain? Do I need to add some kind of diverter? Or should I just leave it alone and screw something else up?

I see two tiny phillips head screws and some kind of stub in the middle. Do I just unscrew the screws, being very careful not to drop them in the engine? Wil the grille piece just slide out when I do that?

Any ideas in giving the scoop more functionality would be appreciated.

 

IIRC, in one of the threads (perhaps from Alta?) in the Drivetrain Mods forum there was a comment that routing the scoop air into a CAI caused the engine to run cooler. The point was that air coming in the scoop increased the air pressure in the engine compartment. So, less air came in through the radiator. Run the scoop air directly into the engine (none going into the engine compartment) and the engine compartment pressure drops -- allowing more air to come through the radiator.

From that, I would guess there was a reason BMW engineers didn't completely open the scoop on the R56 MCS. They compromised by opening some holes to allow trapped heat to escape after the engine was turned off, yet didn't allow much in while driving.

When you convert to a CAI, you probably want to open up the scoop grille. Before then, it might not be such a good idea.

 

Pressure and Velocity are inversely proportional. If you have a high speed flow you will have low pressure, if you have low speed you have high pressure.

Like a wing, have a curve on the top to create higher speed and hence lower pressure to cause lift, or the front of the plane has high pressure on the nose and the flow there is zero (stagnation).

Flow under the car is highspeed and the flow at a pressure point like the intake scoop entrace is high pressure but is low pressre and highspeed in the engine bay since it is sucked out from the highspeed flow under the car.

 

Wow these posts are making me DIZZY!

When I bought a chrome scoop I found very good directions here regarding removal/replacement. It was interesting to find the chrome scoop had no openings whatsoever while the stock scoop had just a few. I switched the grills on the scoops to have some venting rather than none. Removing & replacing the scoop grill is easy while on your lap. Check into removing the entire scoop to do your job...and then replacing it. It's a 5-10 minute task.

 

I think the biggest opening is under the car. A few wholes? I don't know if it will be so critical.

 

Nice physics lesson, but I don't quite get the point you were making, if there was one.

Under the car is where air exits the engine bay. It is a low pressure area. Air enters through the grille and scoop -- the outside of which are high pressure areas. Close the scoop and more enters through the grille and thus passes through the radiator. Open the scoop up and less air goes through the radiator.

 

the mass flow from the radiator does not effect the mass flow from the hood scoop since they are not a closed system.

My point before was the the holes does not effect the radiator at all.

 

I'm not understanding this logic. How does opening the scoop up divert more/less air anywhere? The same amount of air is going to pass through the radiator. Now, instead of just passing over the hood, some air is going to go through the scoop and into the engine bay. Does that make sense?

Opening the scoop is not going to divert air away from the rest of the car. I mean the intercooler is right up front. It's already getting hit with a ton of air as you drive. Opening up the scoop will just allow the 'lost' air that passes of over the hood to make it through the scoop and into the engine bay.

I can't see it doing anything but helping get more 'cool' air into and even out of the engine bay.

 

Basically how it works is that with the scoop closed, there is little pressure on the engine side of the radiator, kind of like an empty vessel, so it is easy for the air to get through the radiator to the engine side. However, once you open up the scoop, you will have air pressure on the engine side of the radiator, pushing against the radiator from the engine side. Now, the air coming across the radiator from the front must push against this extra force pushing on the radiator from the engine side thereby decreasing overall air pressure across the radiator.


That is the principle, but I’m not sure how it plays out in real life. From what I remember, Alta’s testing showed lower temperatures with the scoop open, but I would be interested in knowing for sure as well so I can remove my scoop grill.

 

Very intersting thread in fact, I am about to remove my scoop to repaint it black. I also noticed my scop is totally shut; I hope someone finds any definite answers as to opening it up a bit...

 

I sincerely doubt the scoop is pressurizing the engine compartment. If that were the case, keeping it closed will slow the car down.

Take a plastic cup. Hold it out the window open end forward. It wants to blow out of your hand. Now cut the bottom off the cup and repeat. The air is now passing through the cup and is easier to hold. The scoop is doinf the same thing.

There's too much space for air to escape. If opening up the scoop added pressure to the engine compartment, so would air running through through the radiator. In either case, if it couldn't escape fast enough, you'd have truoble.

 

yah... no idea, I was just putting forth the theory behind what I think they were getting it. But I'm not sure if you're example goes along with what the theory is. I'm not sure what you mean by you highly doubt it pressurizes the engine compartment. If there is now greater airflow as opposed to no air flow, then there is increased pressure. I'm also not sure what you mean by that it would slow the car down, the pressure is insignificant for the movement of the car, but I think the concern is that it is essential for the cooling of the car, ie the air moving through the radiator, if it results in decreased movement of air through the radiator, it also possibly means decreased cooling.

 

Where do you guys work, NASA?

 

No, but I stayed at a Holiday Inn Express last night...

 

 

Think of the engine compartment as a box. Air can escape from it out the bottom, under the car. The space under the car has a certain air pressure -- hopefully lower than outside air pressure.

Air can enter through the radiator and intercooler. The amount of air coming through these entrances will depend on the air pressure in front of them vs. the air pressure behind them.

So, open another hole in the box (the scoop) that has pressure in front of it. What happens? You have more air coming into the box, increasing the air pressure inside the box. So, the pressure difference is not as great as it was between the air in front of the radiator & intercooler and air behind them. Less differential in pressure, less air moving through the radiator & intercollor. Less air moving through, less cooling takes place.

To make the example extreme, let's say you had a bunch of huge scoops funneling air into the engine compartment. The scoops were so big that at speed, there was the same amount of air pressure inside the engine compartment as there was in front of the car (imagine a scoop that looked like a big funnel) No air would pass through the radiator.

I don't work at NASA, but software I published was used at JPL.

 

Your theroy is flawed because in reality the pressure at the front of the radiator or any flat surface is very high at speed relative to any other pressure inside the engine, the differental created from the front pressure, not the higher speed flow behind it but off it could help. Like i mentioned before, the low speed in front causes the high pressure.

I don't work for NASA, they don't design cars.

 

Jascooper,

I just removed my intake cover today and drilled all the large holes out. This is the process:

1: Remove the rubber grommet from the underneath side of the hood (directly below to the scoop)
2: Remove the Torx screw under the grommet hole
3: Move to the back of scoop (opposite end of the grommet/torx screw) and you'll see a gray plastic insert: gently compress the two prongs with a pair of needle nose pliars and move the insert up about 1/8"
4: You can now move your fingers underneath the small gap you made in step 3 and slowly remove the scoop by gently pulling up on the six plastic insert pins (there are one in each corner and one on the front and back as well)
5: Once removed, there are four phillips screws holding the plastic intake scoop in-place
6: Use a 3mm drill bit and a dremel tool and slowly make pilot holes in the ones you want open.
7: Once the pilot holes are drilled, you can use the drill bit to move around inside each opening and clean out the excess material

It took me about 45 minutes to open all the exposed holes and clean them out.

Hope this helps

 

1st, Thanks Robb

2nd If those scoops are creating more pressure inside the engine compartment, then keeping them closed is increasing drag on the car, and slowing it down. (see cup example above)

 

Well, it's been a long time since I took physics but can tell you this:

The BMW/Mini dealer here in Germany where I take my car, the owner has an '07 he tricked out (using his own brand of parts) to gain 230hp. He takes it to a local race track, called Neurenburg Ring. He totally removed the plastic insert and as well installed carbon fiber louvers on both sides of the hood to let the heat vent out (i.e. he's created even more under hood pressure).

I know for a fact he averages 120mph around the track, and gets close to 160mph on a few of the long straights. His car keeps cool from a radiator perspective, and he doesn't have any lift characteristics either.

So... removing the small plastic insert or drilling the additional holes can only help. I decided on the later, because it want to keep water from entering the engine bay. The holes are just the right size to let air in, keep the H2O out.

Cheers mate

 

Awesome how-to!

 

It did! Thanks a ton. I was just about to ask the same question requesting directions. Thanks!

 

I removed my scoop plug and drove through hard rain . When I got back to my house in the garage I looked and the engine was dry.

 

im sure the amount of water that gets in through the scoop is nominal... now i know there are some Subie owners on this site and on their turbo models, the hoodscoop is way more open then the MCS and they have no problems when it rains.

 

Please report if there are any changes in your water temp levels.