JCW intake flap
 

I have a 2004 MCS + JCW + JCW upgrade. I had the upgrade installed yesterday by Brent at Century Mini in Greenville, SC. On the way home to Charlotte last night, I could not detect the intake flap opening at 4500rpm or at any other time. The sc whine and engine noise remain the same. The car is faster however, about as much as you'd expect from a 10hp gain. I spoke to Brent this morning, and he confessed he has never heard anything at 4500rpm and he's installed ten upgrades. I'm wondering if the flap is stuck open. What has been the experience of other NAM members with the JCW upgrade installed? Thanks for the help!

Tom Lamano

The flap on my upgrade definitely opens at 4500 rpm. It is a real kick when just over 4000rpm the electronic valve on the intake opens and you hear a distinctive sc whine that was not there prior to the upgrade.

You can verify that it is opening by raising the hood and watching the flap as someone rev's it to 4500 RPM. That is how the mechanics tested it at the completion of the install.

My JCW Intake's flap definitely opens...
 

I had a new JCW Intake installed by Crevier Mini and I can definitely hear it opening up at 4500 RPM. You'll hear the muted/subtle supercharger whine spooling up below 4500 RPM, but once you cross 4500, it becomes much louder and insistent. Pretty cool actually, one more audible cue to help you time your shifts. Perhaps they didn't hook it up right and the servo isn't actually opening up or maybe you can't hear it over your exhaust (if you've put on a louder exhaust than stock)?

Dave

I can hear the SC scream at 4500 and can feel the extra bit of punch. :grin:

I cannot detect the flap opening in my car, other than feeling the extra punch and hearing a noticeable whistle above 4500 rpm :grin:. Very smooth.

It's not like my S2000's VTEC where you can (if you listen closely) hear a click when it changes cam lobes.

I took my flap out...I like it!


Dave

While we're on this topic, can someone explain to me what's going on here? I'm not really sure I understand how the JCW intake - and the other CAIs on the market - work.

I've seen pictures that make the JCW intake look a lot like the stock aircleaner box. I assume the airflow path is the same as stock? (At least until the flap opens.) In through the little vent just above and behind the radiator, through the hose to the bottom of the aircleaner box, up through the aircleaner, and down the other hose into the throttle body?

And then this flap - does this open into the cowl vent area? So the part from the radiator to the bottom of the aircleaner box is bypassed?

So when the flap opens, it's like the CAIs on the market? (If I'm understanding how the CAIs work.)

So what you've really got is a flap that makes it work like the stock intake at lower RPMs and like a CAI at higher RPMs?

So is the only advantage here (aside from warranty questions) is that the JCW intake is quieter at lower RPMs?

The JCW airbox sucks more air at 4500rpm+ by opening into the cowl vent area. The front intake remains active. Think of the Alta CAI with a modified cowl.

Yes, it is quiet below 4500rpm. This was, as I understand it, derived from the European noise laws. They like to quiet things down a bit over there. Headlight flashes have replaced honking horns in the cities for quite some time. BIG fines for being noisy.
Ian Cull has an excellent write up and photos on his blog GBMINI. One of the photos shows the JCW cone air filter.

the only really useful function of the flap is that it shows how poor the stock intake is without the cowl induction. there is no performance reason not to leave it open all the time.

flap and noise
 

I second the comment above about noise and the flap.

In the paper that the engineers wrote to show how they boosted the MC to an MCS, they mention that they deliberately put on a louder exhaust. This meant that they had to quiet the rest of the car, including the air intake system in order to keep it with in noise limits.

Once you are over 4500 rpm and moving down the road, the intake noise is probably not a problem, so then you can go to the flap open, noisier intake.

The paper is at.
http://www.mini2.com/pdf/mcs_powertrain_us.pdf

Does anyone have a picture of the "modified cowl"? I have the Alta CAI and would be interested in the modified cowl if it is possible and give at least some gain (like 1/16 hp :grin: ).

Earl

Earl,
We did minidoc's cowl by cutting two 2 inch holes. Nice neat holes and looks very much like an OEM intention. There most likely is a 1/32HP reduction for a bit quieter intake.

The modification being done is drilling holes in the partition between the engine bay and cowl area:

http://www.webbmotorsports.com/howto...s/fcde373e.jpg

If you have the Alta intake this partition has been removed :wink:

How many of you guys had an aftermarket intake prior to getting the JCW intake? My sc whined loudly with my MaxVelocity intake and Mini Madness cowl mod. It's not nearly as loud now but it does whine. Maybe my ears are just used to hearing the whine. Thanks for all the input!

Regards,

Tom

Mini-Madness sells a replacement panel cowl mod for $39.00. I have one and it fit well with my MaxVelocity intake.

Tom

I used to have a 95 Integra GSR, you definitely knew when the vtec kicked in (5800rpm?), it sounded like a different engine, and you were moving a lot faster.

Tom

Elcorrectomundo :razz: This has been removed when Randy Webb installed my Alta CAI. :grin:

Now if I understand this correctly JCW install an opening but puts a flap on it so it is closed below 4500 and opens above 4500 rpm? That sounds like a lot of $$$ for no reason to me. :confused: :confused:

Thanks for the reply.

Earl

I think the "reason" is so that the car is quiet when you're driving "normally" but still getting lots of air into the engine (and cool sounds) when you're on it.

This sounds to me like a best-of-both-worlds kind of mod. Only problem is the $450 - ouch!

The JCW engine upgrade parts - the full Works kit as well as the air filter - offer an "elegant upgrade" at a cost.
For a long time there have been aftermarket air filters that offer a brute force solution to air flow - no air box at all, or cut into the cowl to get more air from the vent under the windshield, etc.
The JCW solution offers the "elegance" of quiet refined performance for normal driving, coupled with brute force when needed at high revs. And yes you pay more for it!

By the way, on the subject of paying more for it, I heard this week that a replacement filter for the JCW is $160.

$160 for the filter :eek2: ! Sure hope K&N creates one soon!

I just got my upgrade installed about two weeks ago and love it. Can't beat that Eaton 45 whine when she starts heavy breathing at 4500 RPM :thumbsup: !

Aloha!

JCW04

The volume of air, the shape and length of the intake path, the pressure and velocity of the air - at a given rpm, must be considered. Too much air mass or velocity at low engine speeds may reduce torque for example. Think of the JCW air box as a variable rpm air box.