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The Intake System

50K views 137 replies 66 participants last post by  goaliemo 
#1 · (Edited)
What does the intake system do for your car?
The Intake system in any car is responsible for allowing the engine to breathe and helps your engine run cool. Why would you want to replace your stock intake system? It's a great DIY to get your hands dirty on your cobalt, it's a cheap easy mod that frees up some ponies, and it can improve your fuel economy as well.
--Your basic intake system (such as on our cars) includes--

1. The Intake
2. The Filter
3. The MAF Sensor (Mass Airflow Sensor) which we have or a MAP sensor (Mass Manifold Pressure Sensor).
4. The Throttle Body
5. The Intake Manifold

(*)SAI or Secondary Air Injection (On late 2006+ Cobalt L61 equipped)



The Intake
Why get an aftermarket intake system? Our stock airboxes are very restrictive. By allowing our engines to run cooler and breathe easier, we can FREE UP more power. It is important to note that an intake is not a power adder but a power free-er. There are also two types of intakes which are explained in this write-up: http://www.yourcobalt.com/forums/engine-mods/7885-starters-bolt-performance-mod-list.html

The Filter
There are two major types of filters. The first type offered by AEM is a dryflow filter meaning there is no additive oil. The problem with this oil is that it can effectively ruin the Mass Airflow Sensor. Of course many companies offer oiled filters with their systems such as K&N. The filter does just what it states: it filters the incoming air so we don't get any junk in the air in our combustion chamber. The stock filter is somewhat restrictive and doesn't let as much air into the intake piping as teh material that is used in aftermarket filters.

The MAF (Mass Airflow Sensor)
The MAF sensor senses the intake charge coming into the engine so the ECU (Engine Control Unit) knows how much fuel to deliver via the fuel injection system. The air mass coming into constantly changes from temperature (cold air is denser than warm air). Why is this important? If your ECU supplies too little or too much fuel, your performance is greatly effected and detonation can occur. That's why you MAF sensor is your friend.

The Throttle Body
The Throttle body allows the incoming air from the intake into the intake manifold via a butterfly valve. The butterfly valve is opened when the electronic throttle receives the signal that the gas has been pressed. Throttle body size can have an effect on throttle response, horsepower, and torque. The usual rule of thumb is a larger TB will yield better throttle response and higher horsepower because of the larger airflow. However, if you cannot tune for this and you increase your throttle body dimensions by a substantial amount, you can make your car run lean and possibly cause a fuel surge. A fuel surge is a surge of fuel from the ECU because the engine senses a lot more air so it delivers a large amount of fuel at once but sparactically. I'm not sure if our cars do this or not. It may throw the car into Limp mode because of running too lean meaning the car is at a reduced power level.

The Intake Manifold
What is the intake manifold? An intake manifold receives the air coming from the intake, through the butterfly valve of the throttle body, and evenly distributes the air into the ports in cylinder head via runners (true for port injection). There has been much debate on here about the 2.4L SS/NA manifold swap onto the 2.2L L61 motor. The major problem is that low end torque is decreased when longer, thinner runners of the SS manifold are sending the air charge to the ports. There is an increase in upper RPM horsepower and small increase in torque but a low end loss in torque is evident. That is why it is a better idea to get a free flowing exaust as well as a free flowing Intake system. Though this may sound like a lot, for roughly 800 dollars, you can gain approximately 20-25hp which isn't bad.

Here is the SS/NA manifold replacement kit for the 2.2L: Ecotec HO Intake Manifold Kit 2.2MMGF - Crate Engine Depot

The reason this changes the low end torque is because the incoming intake velocity is altered.

Secondary Air Injection
In Late model 2006 and up models of the L61 level cobalts, GM implemented a system called SAI or Secondary Air Injection. SAI is basically an emissions conrtol device and is basically a hose after the MAF and before the throttle body connection to the engine on a small port. Basically (from what I understand) air comes into the intake from the filter, up the intake piping and the SAI takes some of that air and pumps that to mix with the exaust fumes to affectively lower the emissions. It's important to note when buying an intake system if you have SAI or not.

I hope this sheds some light into why an intake system is so important. Again, a cooler engine is a happier engine! Happy modding.
 
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#2 ·
Great Write Up ....Any newbies to Modifying should read up on this
 
#5 ·
Thanks man this may eliminate what intake is better, wha is an intake, blah blah kinda questions. We used to have tons of those.
 
G
#6 ·
I have a question.

Last summer I had a friend (before he was reassigned by the Air Force) who was running stage 2 on his 07 IRL and got the saturn motorsports big bre throttle body. He said he noticed the difference between before and after installation. He claimed he ran faster than the supercharged police dodge chargers with the 5.7's. Anyways, he said it came with a tune that was done by the dealership. Just how beneficial would a larger throttlebody be on the LSJ's? I've been considering purchasing this very soon, then getting stage 2. Also, due to the fact that the diameter of the tb is larger than oem, it has been recommended that i have the snout of the supercharger be machined to the same diameter. Is this going to be necessary?

Here is the part I'm referencing:
Saturn Motorsports
 
#7 ·
Not to call your friend a liar but I don't believe what he is saying. The intake side of the LSJ flows very well and even with snout machining the supercharger is still the stumbling block and it's not due to air flow, but heat. In my opinion your money would be spent better elsewhere. Particularly on cooling and traction mods.
 
#11 ·
I have a K&N air intake system on my cobalt,it helps out for sure
 
#13 ·
GM Performance Air Intake

Does anyone know how much the GM Performance Air Intake is if i bought it throught he dealer and had them install it?
 
#14 ·
somewhere near 350-400 dollars more than likely with dealer installation. I had one ordered thru the dealer i bought my car at and the original price was well above 300 not counting the installation itself. Mine was never done however because i was one of the lucky cobalt owners who have the SAI so they couldn't do it, so i never knew what the final price would have been. I was forced to go with K&N instead....
 
#15 ·
Nice, would the GM intake make enough difference in performance and quality to justify the dent in the wallet?
 
#17 ·
actually let me recommend you going to murrays auto discount store.They have the K&N intake system,they will order it for you and no shipping payment involved,also you get a 15% discount on it so I paid 215 dollars for it instead of 280 dollars.
 
#21 ·
oh well at least the K&N is lifetime warranty still if something goes wrong but their product is built well
 
#22 ·
Is it possible to tune the air/gas mixture. I built my own intake using the OEM throttle cover an just ran pipes down from there(it was a Cold air) then ran the pipes down behind the headlight....the check engine light came on. Got the codes, it was my O2 sensor. Any Body help?
 
#25 ·
Good write up. But, you might want to note that not all 2006+ cobalts have the SAI. I have a 2008 ls and mine does not have it.
 
#28 ·
Sadly I'm not on that much anymore. Since I got my mustang iIve gotten outta the cobalt game.
 
#26 ·
My 2007 does not have SAI.
 
#29 ·
ok i put in another intake and it was all good until my check engine came on i checked it was my o2 sensor. my air fuel mixture is running lean. but its not dumping gas like it was last time any help?
 
#30 ·
ok i have a question i have and 2006 cobalt lt coupe it came with a pioneer deck and a K&N cold air intake i want to know if that was something that chevrolet threw in to up sales or was that after market because i've asked around an people are saying chevy threw it in and some say aftermarket do u guys have any knowledge of that?
 
#31 ·
If the dealer installed them the window sticker (not the original window sticker but a dealer printed one) would show them as dealer add-ons. Usualy when the dealers install items like that they put some kind of graphics on the car too (like Ecotech RS, Z61, GTX, Special Edition, etc).

If you bought the LT used they were most likely installed by the owner.
 
#33 ·
That manifold is on my list of mods to get. It is a great performance mod for the 2.2 especially for the price. However if you do not drive your car spiritedly it is a waste. The manifold is only good for your top end, and (slightly) hurtful for your low end torque. It just basically shifts your power band upward.
 
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