I recently purchased a JCW Intake and installed it last night. Every user review I have heard makes reference to the noticeable difference in sound when the car hits 4,500 RPM and the valve opens.

I hear no such sound and am convinced that the valve is not opening.

What could be wrong? Or more specifically, what part of the install actually controls/involves the valve?

Also, have others found that the intake is barely louder than stock? I prefer to have as much performance with as little noise, so I'm certainly not complaining. But I have to admit...I was looking forward to a little extra yelp at 4,500.

 

I recently installed the JCW airbox also. I left the lower hole blocked like it comes in the end.

In playing with the JCW box I found the following:
With the lower hole blocked the sound is less/equal to factory up until 4,500rpm, then it is a little louder than stock;
With the lower hole blocked the low end torque is a better than stock;
The stock airbox is designed as a compromise- i.e. the open stock lower hole is small enough for low-end tourque and big enough to allow the extra air for some extra high end HP;
With the lower hole blocked on the JCW box, there is better than stock low-end starting torque and then there is better than stock High-end HP;

Apparently the goal with the JCW box was not to increase sound, but increase power all-around. It does a very good job at this.

If you remove the lower block, the low end sound is louder but about the same as stock, but the high end (after the valve opens) is noticably louder than stock. I am not talking about AGS or ALTA louder, but louder. The issue with removing the lower block is losing the low-end torque.

My problem is that I miss the SC sound and end up reving higher to hear the SC above 4,500. But I like the better low-end. Eventually I will get used to it and keep the revs down unless needed. Then I will get used to quiet power around town. If I don't get used to it I will just need to lose the low-end torque and remove the lower block so that I can enjoy the sound at low speed.

I think that if you have a pulley installed, you may want to remove the lower block for better breathing earlier.

 

Thanks for the reply.

Sorry to sound like a complete n00b, but what are you referring to when you say "lower block" or "lower hole blocked."

I guess what I'm really wondering is whether or not I have everything installed properly. Is there any way I can tell whether or not the valve is opening? Also, what wire/hose is responsible for the activation of that valve.

There is ZERO change in sound for me.

 

I just remembered!
Important note: When I looked inside the top of the airbox before I installed this kit, I found that the incoming vacuum supply tube was for some reason never connected to the vacuum canister/reservoir. (JCW Quality Control?) This may be the case on yours also!! I had to remove the canister holding strap, install the vacuum hose, reinstall the canister rotated for more length for the incoming vacuum hose, and reinstall the canister strap. Check this issue out if your is not working!!!!

{what are you referring to when you say "lower block" or "lower hole blocked."}

The JCW airbox has a top and bottom half. The bottom half looks to be exactly the same as stock. The top has the new butterfly valve that opens, the new filter, and the vacuum tank/mechanism, etc. The bottom half has the stock air hole from the front ram air and the stock air hole from the cowl (rear) pressurized air. The JCW box bottom has both of those same air holes, but the JCW comes with the lower cowl (rear) air hole blocked with a round piece of plastic inserted in the accordian grommet. With the JCW kit you should have also gotten a new engine bay rear "wall" for the drivers side. That wall has holes in it for both the stock lower cowl (rear) air hole accordian grommet and new upper BIGGER butterfly valve accordian/grommet.

{I guess what I'm really wondering is whether or not I have everything installed properly. Is there any way I can tell whether or not the valve is opening?}

If the loose vacuum connection I mentioned above is fixed and the wall and the new top and bottom are installed correctly, then you only need to make sure that your wires and vacuum supply are hooked-up correctly.
1 wire (Black) is your ground, 1 wire is your power from the fuse box that you insert in the connector body, and the 1 remaining splice-in wire is your valve opening signal wire.
The vacuum supply was most difficult for me. My hands were too big to reach the bypass valve easily. You may need to remove the intercooler to reach this area easier. Once you get this "T" installed on the bypass valve and get the original tube connected to that "T", then you just need to find the best way to run the vacuum signal up to the vacuum connector coming out of the top of the airbox.

{Also, what wire/hose is responsible for the activation of that valve.}

The pre-SC vacuum is providing the valve opening force, and the power that actuates the vacuum solenoid comes from the 3 wiring connections to the connector that plugs in to the top of the JCW airbox.

If you can stand it, just open the hood while the car is idling in neutral, reach you hand down behind that wall till you can feel the butterfly valve closed and have someone slowly raise the RPMs above 4,500 and feel/listen if that valve opens. It is pretty high up and should be easy to feel. Just make sure you get your fingers out of the way before the person lowers the RPMs below 4,500 again!!!

 

A very common problem is no contact with the red wire due to improper installation.

I would have had some difficulty if it wasn't for Greatbear's post #3 here: https://www.northamericanmotoring.co...ad.php?t=40358

 

I'd say the first thing is to look into the fuse box connection. Make sure the wire is 'locked' in place. To do this you'll need to unlock the fuse connections install the wire and then relock the fuse box connections. I had the same problem until this connection was installed properly. There are a couple of install how to's here on NAM that helped me out with the details (not in the factory install instructions) that explain in much better than I just did. The other thing would be sure to check that the vacuum line in installed correctly with the hose slide on connections snug and hooked up to the right line.

 

Ditto.
I reached back up and could feel that the flap was not opening. Then worked on ensuring that the red connector into the fuse-block was REALLy connected. After that I could feel that the flap was actually opening.
But I have to say that I can't tell if there's any audible difference.

 

Great tips. Does the ECU need to be reflashed if you are installing only the airbox?

 

NO!

 

I thought that you must purchase the JCW software along with the JCW airbox. It has the required programming to set the valve to open at 4500rpm, I think... If there is an alternative, I havent heard about it..

 

Nope. No programming required for the airbox.

 

Verified. Flaps opens at 4500rpm with NO reprograming. Of course now I have to buy a new ECU cover to replace the one I broke a clip off of.

 

Perhaps I ought to check these components as there is no discernable sound difference above 4,500 rpm for my 05 JCW...

 

I just noticed you have two threads going - mods how bout shutting one down?


https://www.northamericanmotoring.co...ad.php?t=46705

 

Jussnb

use a pair of needle nose pliers and make sure the red wire is REALLY conected to the pin...I did a JCW install for a friend and this was our problem...

if you really wanna know if it's opening or not...stick your hand in there and touch the flap...then have a friend rev out to 6k and if it doesn't open...you have your answer...

Like I said, you prolly just didn't get that pin in there far enough...

Chris

P.S. do you have the directions? if not I do and would be happy to get em to ya

 

Don't push the pin...as I noted in the other thread, look for my old thread on install tips, it's hows you how to connect it.

 

[QUOTE=ewoster].....
In playing with the JCW box I found the following:....
With the lower hole blocked the low end torque is a better than stock;
The stock airbox is designed as a compromise- i.e. the open stock lower hole is small enough for low-end tourque and big enough to allow the extra air for some extra high end HP;
With the lower hole blocked on the JCW box, there is better than stock low-end starting torque and then there is better than stock High-end HP;.....
[QUOTE]

how can this be? is this just a butt-dnyo guess or did you really dyno the car? can anybody out there explain this?

 

It's easy to visually compare the pin to the others in the connector. If it doesn't look the same it isn't seated properly. My flap opens at 4500 but I don't get that intoxicating whine until about 5000rpm. I don't notice any power bump at that rpm but the throttle response might be a hair sharper overall.

 

When intake volume is decreased (plugged hole), velocity is increased. That's why the JCW has better torque than an open cone.

 

i still don't get it. if we had a na engine, i could understand a "tuned" intake runner with a timed pressure pulse helping to stuff the cylinder, but with the sc i don't see how decreasing the area can help anything. the smaller opening/higher velocity flow will have a greater pressure drop, thus "losing" energy in the flow that could otherwise be converted to power.

 

I agree completely. The smaller intake opening would increase air velocity thru the opening itself, but once the path opened up thru the filter and air hose the velocity would drop (ultimately to a lower value than if a larger intake hole were used, since the smaller hole decreases the total mass flow). Also, switching the restrictive stock air box to an HAI did not reduce the low rpm torque in my car, and the HAI would have the lowest air velocity of any intake.

 

I'm not a mechanic or engineer so I won't try to address why JCW went with a flap, I can only think that of all brands they likely did the most R&D and found it beneficial for some reason. Perhaps someone has/can contact them directly to get the final word on it?

All that is said on the site is:
"The unforgettably throaty sound of the engine will register instantly in your ears. There is a second air intake controlled by means of an electronically actuated flap, which opens during acceleration at 4 500 rpm. The result is a significantly improved performance curve and an even more distinctive sound."

 

The performance reason for the flap opening at specifically 4500 rpm sounds awesome (and I hope this is the case as I have the intake on my car) but it seems I remember reading on here or somewhere else that the real reason was because of european noise regulations... It could just be a rumor though.

 

ok, adding to the rumor mill was the speculation that having it closed at lower rpms would keep out water. the thinking was that in really wet weather you wouldn't be at full throttle...

 

and to continue on that train of thought, wouldn't the really wet weather also wash away some of the added sound benefit from the open flap?