Here's the deal: I've got an 05 MCS. I really love listening to the engine, supercharger, intake, and exhaust sounds when I'm driving, but I also like to listen to my stereo when I'm stuck in traffic or just cruising down the highway. For the latter conditions, I don't want the car to be any louder than she is now. But I keep reading about all the delicious sounds people are getting from CAIs and HAIs and JCW intakes, and drooling. It seems to me that the 05 JCW intake (which only opens when you're "on it") would be just about perfect.

Except for the price!

So I started thinking about basically a DIY JCW intake. Cut adjoining holes in the cowl and the back of the stock filter box, seal the space between with some foam weatherstrip, and put some sort of cable-operated (or if you want to be really fancy, solenoid-operated) flap there that will open or close the cowl-to-filter box opening.

This wouldn't need to be some sort of automatic, vacuum- or rev-operated deal. Manual would work great - pull the **** or flip the switch. Open the flap for fun, close it for tunes. (Other old farts may recognize my inspiration for this idea - the old cable operated exhaust cutouts JCW(hitney) used to sell. Always wanted one of those!)

I haven't looked in there to see how feasible this would be, but it was a fun idea that I flashed on last night as I turned off the main road to enter a little twisty near my home, and turned off the stereo at the same time.

Whaddya think?

(Notice I haven't mentioned performance anywhere. I get the impression that most intakes only add 2-3 hp at best, so I'm looking mainly at the "fun factor" here. I'm also hoping Alta or M7 or Pilo or somebody is reading this. I'd pay probably pay $225 - about half the price of the JCW intake - for something like this, but $450? No way!)

 

The Dinan cold air intake is similar to the JCW intake except there is no flap that opens, it is always open. I have the JCW intake and there is no noticeable difference in sound with or without the flap open. You would be wasting your time providing a manual opener for both sound and performance.

 

I have the HAI and the only time it gets loud is when I stomp the gas. All other times you can kinda hear it but you have to have the windows down and be listening for it.

 

I have the Alta CAI. I love it the sound that comes out is sweet . Ive had it on my car for awhile now. I know your not looking for any gains except sound but the alta isnt that bad when you are just doin normal driving. You do hear the intake sucking in and whistleing alittle bit. But a simple turn of the volume can drown that out. And then under hard acceleration you can get your passenger that doesnt know anything about the car go "what the hell is that noise?"

 

If you're not hearing any difference in sound with your JCW intake after 4,500 RPM then the flap must not be opening properly on your car. I have two 05 cars with the JCW airbox in them and there's a HUGE difference in sound once the flap opens. When I'm inside the car and the tach hits 4,500 RPM there's an awesome wine that kicks up from the supercharger and you really know that the flap had popped open.

 

I know that your thread is titled the "Poor Man's JCW Intake", but there's another thing to point out about the JCW airbox that you'd be missing with your "poor man's" version. The JCW airbox (while the same on the outside as the stock airbox) uses a large conical air filter element inside (for greatly increased air flow) that is very different from the stock flat panel air filter element.

However, I do agree that a poor man's version would be easy to build out of your existing airbox and would probably still give you the nice supercharger wine even without the conical air filter element (as long as you pop the holes all the way through the plastic firewall). Besides that, if you happen to mess your stock one up, you could always buy another stock airbox very cheep from someone who has replaced their's for the JCW one. I know that I have two of them just sitting in my garage taking up space.

 

officemavin if you are refering to the supercharger whine, then yes I do hear it at 4500 rpm. My air box was checked out and it does open at 4500 rpm. Most CAI create a "air sucking" sound when you get on the gas. The JCW intake does not. I prefer the subdued sound that is created. I have had my JCW intake from the day I picked up the car so it is possible that the sound for a non JCW intake car allows less supercharger whine.

 

The stock air box already has an opening to the cowl area ...



Unless you replace the stock panel filter with a conical filter, any hole cutting would be restricted to the area of the existing hole (below the panel filter).

 

The JCW intake also has the same lower opening into the cowl area in addition to the big 'flapper' opening. Out of the box, the JCW intake has a plastic disk installed in the rubber 'boot' that connects the airbox to the cowl partition. This disk is easily removed before the lower airbox is installed. What you end up with is a 'two stage' cold air opening with the lower one open at all times and then the large one kicking open at 4500rpm. Disadvantage (or advantage, to some folk) is that with the lower opening uncorked, you tend to hear more of the whine in the lower rev ranges making the opening of the flap less noticeable. I uncovered the lower port in my intake. The sound is great at all rev ranges IMO.

 

Yes, that's one of the things I really like about the JCW airbox. i.e. you don't get that loud sucking sound at the low RPMs. I have a K&N filter on my Jeep and it drives me nuts with that sound. I think the JCW airbox is very refined and very well designed too (as it is quiet at the low RPMs and sounds great when you put your foot in it). I have a friend that has one of the ALTA CIAs and I don't have anything against it, but for me, it's just a bit too loud for everyday driving.

 

I thought about doing this same thing when installing my own JCW airbox (it's easy just to use the stock plug with the hole in it vs. using the JCW plug that's covered up when first installing the airbox). However, I wasn't sure if doing so would do anything to the low end power on the car (i.e. maybe they designed the airbox so that it is a little more restrictive at the low RPMs for a reason???). I figured that the guys who designed the airbox knew what they were doing and so I just left it plugged (as stated in the installation instructions). I'm sure that you are right though and that they simply did it so that when the main
(i.e. large) flap opens you really hear the wine of the supercharger kick in (above 4,500 RPM). I can always open it up later on if I want to.

 

The JCW airbox is designed to have less air at lower RPMs, which keeps the air/fuel mixture close to optimal, at the higher RPMs when additional air is added there is also additional fuel (larger injectors are included with the kit).

 

Yes, that may be true, but MINI also sells just the JCW airbox (without the larger injectors) for use on non-JCW MINIs. That's the one I bought (although I'm kicking myself now for now paying the extra $70 for the kit with the larger injectors as they're worth probably three or four times that amount on the aftermarket now - the stock injectors are $125 EACH from the dealer! ).

 

The kit I got had the larger injectors and an ECU flash to optimize the top end. The difference in price was very small.

 

So I could buy the JCW airbox with the injectors (for my otherwise stock 05 MCS) and then sell the injectors and recoup some of the price? Hmmm....

D'ya think people would pay, say $50-60 each for the injectors? That would get me in the ballpark for what I'd be willing to pay for the airbox.

 

Yes you sure can, and yes I do think that folks will pay that much for the injectors. There are lots of folks who want them (for use with their 19% pulleys, etc.) and many of them don't want the JCW airbox as they are already using a different CAI setup. Thus, I'm sure that you'd find quite a few folks willing to pay that much for them.