Except for full throttle and cold starts, our cars run in closed loop mode. The car decides how much fuel to inject based on how much oxygen there is in the exhaust. So if a CAI allows 2% more air to go through the throttle at a given throttle position and RPM, won't the ECU throw in 2% more fuel? I can understand where the power comes from at full throttle and how an intake could slightly lean out the mixture, but that is open loop mode. I can see how a dirty filter would cause the car to enter open loop mode sooner, for example: With a dirty air filter, a driver might have to apply 75% throttle with a dirty filter (possibly in open loop) to get the same power as 50% throttle in closed loop with a clean filter. Does anyone get what I'm saying?

2002 Cavalier 2200 5spd

Keep in mind that the people telling you that a CAI increases mileage are usually the manufacturers and magazine ads. This is the same source that claims that a simple CAI will add 15-20HP on a Cavalier. They will say whatever they think they have to in order to sell as many units as possible.






09:f9:11:02:9d:74:e3:5b:d8:41:56:c5:63

Less restriction = improved flow = more efficent = more mpg and mpre hp. Jimmy there was a dyno test done by someone here on an ECOTEC powered Cavi. and simply by removing the factory intake the car picked up I believe it was 7hp. So can an intake increase hp? Not really but it can get rid of the restrictive factory intake resulting in more hp, but it doesn't make it itself.





Semper Fi SAINT. May you rest in peace.

i have a short ram on my 2.4, i dont think my mileage went up my car always got pretty good mileage(525-550kms per tank) the mileage is still the same..

again jimmyz already said it, they will tell u anything to sell their products...


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ayo 8 Iz Enuff

In theory if the engine's working more efficiently and the intake sucks air in more efficiently you'd get better fuel economy because it takes less work to suck in the air you need for combustion. Obviously though as you said at WOT the economy's gonna drop.

My friend put a catback on his Civic and says he gained 2 mpg on the highway. In that case, sitting at, for example, 3000 rpm at 70 mph with the catback requires less throttle application because the engine makes (slightly) more power and is operating more efficiently.

But let's get serious: if you are concerned about fuel economy, you shouldn't modify your car for performance.




I was happy when I heard my car ran 10s. Then I found out that was 0-60.

I installed an AEM Typhoon series intake for my cavalier and my mpg went up a nice amount. Not only did I gain power, but I can get atleast 290miles before I have to refill my tank. Before on the stock box, I could only get about 250/260, so it was noticable.

I custom made my cold air ram intake, and I can see my gas needle dropping fast :o)

Most intakes should give an increase in mpg, just as JH mentioned above. The problem lies within the driver, whom usually will drive more aggressively, this includes myself!!

SundayNight PegCity wrote:I custom made my cold air ram intake, and I can see my gas needle dropping fast :o)

That is because you need to keep your foot off of the firewall!

But seriously...My intake/exhaust upgrades did improve my gas mileage a bit. I'm usually between 32-35 MPG, unless I drive like an idiot.

I noticed a slight increase with just an intake. but once i had the exhaust done on my car it once again increased. i normally get 24-28 driving back and forth to work and 34-38ish on the highway. all of it depends on your driving style air temp and humidity and elevation. even when i get stupid with the car in town ill atleast get 24mpg. its all in how the car is setup as far as the intake and exhaust.

Despite the mileage increases they try and sell you on, the cost will not make it an economical decision (it will never pay for itself). However it will help with power delivery by removing the restrictive stock air box.

Also the thing eveyone forgets is tthat if your upgrading your car for performance your usually not driving it for optimial fuel mileage all the time.


-Chris

IamRascal wrote:Despite the mileage increases they try and sell you on, the cost will not make it an economical decision (it will never pay for itself). However it will help with power delivery by removing the restrictive stock air box.

Wait, what? If your car was getting oh lets say 30 mpg and you install a $200.00 intake and your mileage jumps to 35 mpg then the intake will in fact pay for itself.

We'll use a nice round figure like 10 gallons to make this easy as possible.
So before the intake you would go 300 miles per tank and after you would go 350 miles per tank, Thats like getting an additional 1.4 gallons of gas in the tank. So at an increase of 50 miles per tank in 142.8 tanks of gas the increased amount of mileage will have paid for itself. And in miles thats 49,980 miles and the intake has in fact paid itself off. True thats alot of miles and its provided you don't drive like a nut and cause the milegae to drop by driving fast.

So see, it can pay for itself in your fuel bill savings but it will take a while.






Edited 1 time(s). Last edited Thursday, July 06, 2006 10:45 AM

Semper Fi SAINT. May you rest in peace.

yeah, and when you hit 100,000 miles...it pays you!

Then you need to buy a new filter because it will be all dirty so now youre back in the red.

Meh, if anything, your intake sounds cool, just get it anyway...

"Less restriction = improved flow = more efficent = more mpg and mpre hp. Jimmy there was a dyno test done by someone here on an ECOTEC powered Cavi. and simply by removing the factory intake the car picked up I believe it was 7hp. So can an intake increase hp? Not really but it can get rid of the restrictive factory intake resulting in more hp, but it doesn't make it itself."

That's only true at WOT. Remember, that at partial throttle, the biggest air restriction by far is the throttle plate and the car will be running in closed loop mode. In closed loop mode, the ECU could care less whether the throttle plate or filter is restricting the air flow, it just matches the air that does get in the motor. I can accept that intakes increase milage in open loop mode, but my car hardly spends any time in open loop.

2002 Cavalier 2200 5spd

Jackalope wrote:So see, it can pay for itself in your fuel bill savings but it will take a while.

Thats also provided that you consistently get the higher fuel mileage. The gain if any in mileage that I've recieved from having an AEM CAI hasn't been realized in my budget, my average fuel costs are the same as they were before I installed it.


-Chris

Really ? Thats weird ! When I did my intake and exhaust my car went from a 3/4 of a tank a week to 1/2 a tank !
That to me is a HUGE difference !

Not starting with ya just saying its weird you didn't notice a mesureable improvement ( shrug ) sorry to hear it man.





Semper Fi SAINT. May you rest in peace.

I installed an AEM CAI, Pacesetter 4->1 ceramic coated header and some exhaust work and my milage increased by 2 to 3 mpg. ('03 5sp Cav) With just the CAI i don't think you'll see much, both should do the trick. Lowering restriction on the intake and not improving the exhaust, your still hitting the restriction on the out.
Don