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Discussion Starter #1 (Edited)
How to Bypass the Intake Resonator

This is a very simple procedure, but several people have requested a write-up showing what needs to be done step by step, so here it is.

This article explains how to bypass the intake resonator and misc plumbing on the Chevy Cruze. Once this modification has been made, the factory airbox will pull air directly from the fender/bumper well area. The purpose is to improve throttle response, increase performance, and hear the turbo and BOV (blow-off valve). Keep in mind, the BOV will only be heard when you accelerate and let off the gas, such as when to shift with the manual transmission.

The factory intake system pulls air from behind the upper front grill (above the Chevy bowtie), wraps around the radiator, around the bumper, into the bumper/fender well, into a resonator box (for the purpose of silencing engine and turbo noise), then up through the bumper/well and into the airbox. The opening for the air duct can be seen through an opening in the front panel with the hood open:


This opening is directly behind the upper grill, which at least on the Cruze Eco is completely sealed off:



My understanding is that the air is pulled from through the hole seen in the first image (hot air from the engine bay), or through openings above the radiator support (also hot air from the engine bay):



In any case, this is all getting bypassed. First step is to loosen the ring clamp on the intake hose. You'll need a flathead screwdriver, like so. Once its loose enough, it should slide right off:



Next, you'll be disconnecting the MAF sensor connector. In this picture, you'll see a red plastic piece. That's the lock that prevents the connector from being removed accidentally.



The lock slides back easily as is seen in the next picture. Once you slide this back, push down on the black tab (surrounded by the lock plastic) and pull the connector out.



Next, disconnect the hose that the red arrow points to. This might take a few seconds, so take your time and don't break something. Keep wiggling it around while pulling it out and it will eventually loosen up and slide out. In blue is the first airbox mounting point.



In the following photo, the second mounting point is shown:



Once you have the intake hose, the MAF connector, and the black tube disconnected, you can simply lift the airbox upward, and it will pull out of the mounts. Once done, you'll see an intake duct that goes down into the resonator box. This is the duct we'll be removing:



Before you remove the duct, stuff a towel down that hole or something of the sort. It will prevent you from dropping the fasteners that you'll need to be removing down there. To remove the duct, we first need to remove the fasteners holding it down. If you look closely, you'll see a section of the fastener with a tab:



You can insert a flathead screwdriver under that tab and twist it to lift the fastener:



Work your way around the edges of the fastener with the screwdriver until you can grab it with your fingers and pull it up out of the anchor. You don't need to pull it completely out, just about this far:



Next, use the screwdriver to do the same with the anchor:



At this point, you're ready to remove the duct. Fit your fingers securely underneath it and pull upward with even pressure. This will take a bit of force, so use both hands and give it a good pull from different locations:



This is what you'll see once you've pulled the duct out; the resonator box. Most likely, there will be a rubber seal still on the resonator box:



Slide the rubber seal off. It should be greased so it will come off easily. It looks like this:



We remove this so that it won't get dirty or dry rot, or get lost somehow. Fit it inside the intake duct you just removed so you don't lose it:



In reverse order, put the anchors back into their original holes, and push down the fasteners. These will stay locked in place so you don't lose them should you decide to put the duct back in:



At this point, you're almost done. Put the airbox back in its place and line up the mounts:




Push down firmly but slowly, and the filter should pop back into its mounting points. Reconnect the MAF sensor connector and push the red lock back in. Put the black hose back in (see picture 7), wiggling it through until it is held inside securely. This might take a bit of coercing.


Reattach the intake hose and tighten the clamp back down. DO NOT OVER-TIGHTEN THE CLAMP. If you over-tighten it, you will risk cracking the airbox. Tighten it just enough to where the hose is securely attached to the airbox.


You'll have effectively bypassed the resonator and intake tubing by removing this intake duct. Store the duct somewhere safe in case you wish to install it again at a later date. Go out for a spin and enjoy the improved throttle response, performance, and the now audible turbo/BOV sounds.

If your fan is on full blast when you start the car again, simply turn it back off, disconnect the battery ground, wait 1 minute, then connect it again.
 

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Discussion Starter #4
In your opinion, does removing this really make a difference?
Yes. The difference in throttle response is immediately noticeable. I very much like having better throttle response. I cannot yet comment on the difference in performance as I haven't yet put it on a dyno and I don't expect it to be more than a few hp. The K&N performance intake gains somewhere around 6hp over stock, so you're probably looking at 3-5hp with this modification. A significant portion of the gains from the K&N intake are from bypassing the resonator and the factory plumbing.

The difference in sound is also very noticeable.
 

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Gonna have to give this a try when i get home tonight? Any idea if you have to put it back in before heading to the dealership for anything, or is this something they wouldn't really notice? Just worried it being a reason to void any type of warranty.
 

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Discussion Starter #7
any improvement to fuel economy?
Can't say for sure yet. I'm inclined to say yes, but I'll have to go a few more tanks of gas in order to tell.

People are claiming to get better fuel economy with the performance intakes out there (Injen, K&N, ZZP), so I'm guessing that anything that improves airflow a bit will improve fuel economy. Someone who has driven their Cruze longer than I have will have to report back in a few months after doing this modification.

I think what will improve fuel economy is your ability to hear the turbo spool. You'll know when it spools that you're sucking in more air and therefore burning more fuel, so you'll start to make a correlation between turbo noise and fuel economy. If you want to burn less gas, drive in such a way so that you hear the turbo as little as possible.

Gonna have to give this a try when i get home tonight? Any idea if you have to put it back in before heading to the dealership for anything, or is this something they wouldn't really notice? Just worried it being a reason to void any type of warranty.
This modification won't void your warranty. The only purpose for the intake system past the airbox is to quiet down engine and turbo noise. By removing it, you will not have modified the filtration of the intake system. The performance intakes that are available do away with the entire system including the airbox and still do not void your warranty.

I highly doubt anyone will be able to tell that you removed it anyway.
 

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Great, wont void warranty! Now I have something else to do when the weather warms up a bit! Great post!
 

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Discussion Starter #10
So the turbo is that noticeable without the extra piping?
Yep. You can't hear it at all with the resonator box still connected. Once you remove it, you'll hear it very clearly.
 

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Awesome write up. Better detailed pics and instructions then most intake manufacturers include. Was thinking of doing this mod but a lot of previous threads talked about removing all the guts behind the fender which entailed removing the bumper and everything else which I'm not comfortable with. This is easily doable and will achieve the same results plus would be just as easy to put back to stock. Thanks man.
 

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That's the easy way. The original way involved removing the front bumper to completely take out that ducting. Glad there's an easier alternative out there!
 

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so what you are saying is that when i do buy my K&N intake this has to be done either way? or the way the K&N is set up it doest grab air from the resonator
 

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I pulled the tubing out a few minutes ago. The turbo can be heard slightly with the windows up. I didn't get to drive but a few miles so I'll have a better view on this tomorrow.
 

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Discussion Starter #16 (Edited)
just buy the SRI/CAI and be done with it?
You're more than welcome to donate $200+ plus shipping so I could install a K&N filter in my car. This requires a flathead screwdriver and you could probably use a butter knife. I'm not yet convinced that there is $200 worth of performance improvement with the K&N performance intake over this modification or any real purpose for it aside from the ability to more loudly hear the turbo and BOV.

That's the easy way. The original way involved removing the front bumper to completely take out that ducting. Glad there's an easier alternative out there!
I'm guessing there's a miniscule benefit to reducing weight by removing the entire plumbing system, but if all you're doing is sucking in air from the fender/bumper well area, there's no point to it, especially if you might at some point sell the car and want to very easily put it back to stock.

so what you are saying is that when i do buy my K&N intake this has to be done either way? or the way the K&N is set up it doest grab air from the resonator
The K&N is a SRI (short ram intake). I don't know what the exact instructions are for the K&N intake, but based on how it functions, it looks like most of the air it pulls will be warm air pulled from the engine bay. I suppose that if you do remove this duct, you have a higher chance of pulling some cooler air from the fenderwell, but the heat shield that it comes with is not enough to block out the warm air enough to force the filter to pull it from the fenderwell.



If you had an OBD2 Bluetooth adapter and an Android phone, you could scan and monitor the IAT temp in identical conditions with and without that duct with the K&N filter installed. My guess is the difference in temperature will be minimal if not nonexistent.
 

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Discussion Starter #17
I pulled the tubing out a few minutes ago. The turbo can be heard slightly with the windows up. I didn't get to drive but a few miles so I'll have a better view on this tomorrow.
You should also notice an improvement in throttle response.

Its worth noting that I was able to hear the turbo quite a bit louder when I installed my K&N drop-in panel filter. It seems that the factory paper filter blocks out a good amount of sound as well.
 

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yea i just removed the resonator and the response is better, but i still can't hear the turbo or BOV :( does this work for the auto trannys too. and i really haven't been under the hood of my car since i bought except to install the HIDs but i just noticed a loud clicking sound while the engine is on does anyone know what it could be or is just normal sry to veer off topic here just worried.
 

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Discussion Starter #19
yea i just removed the resonator and the response is better, but i still can't hear the turbo or BOV :( does this work for the auto trannys too. and i really haven't been under the hood of my car since i bought except to install the HIDs but i just noticed a loud clicking sound while the engine is on does anyone know what it could be or is just normal sry to veer off topic here just worried.
You only hear the BOV when you let off the gas after accelerating, which typically only happens with the manual transmission. It wasn't very loud for me until I dropped a K&N panel filter in there, and you hear it more between 1500 and 2500 RPM. Above that, the engine rev noise seems to drown it out. I'll try to take a video so you know what you're listening for.
 

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You only hear the BOV when you let off the gas after accelerating, which typically only happens with the manual transmission. It wasn't very loud for me until I dropped a K&N panel filter in there, and you hear it more between 1500 and 2500 RPM. Above that, the engine rev noise seems to drown it out. I'll try to take a video so you know what you're listening for.

Can hear mine with a CAI clear as day at 5500RPM...
 
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