intake ?

[screech985]

What is a better intake for better gas millage on an 04 Aveo, RAM or CAI

also what type of power is better, low end or high end

[LarsBud]

I can only speak for myself, but I'm really happy with my short air.

[reddemonx92]

lol theres a post somewhere on the CAI vs. RAM intakes.
I have a CAI on my aveo.

[Daox]

I'd highly suggest reading up a bit more. I can suggest at least this one article:

AutoSpeed.com - Pipe Dreams

You'll notice that pipe length has a fairly drastic effect on the powerband. Longer generally seems to be better, ram airs are very short and won't give you the midrange torque you want. The pipe they found worked best for that engine was 60cm or 24" long. So, the short answer is go with the true CAI.

[petrified.rabbit]

Well said. Ram air and cold air are often only compared at top end and while the engine compartment isn't hot (like hood open on a dyno with a huge fan onfront of the car). So it's important to research benefits and losses throughout the power band, and match those parts to driving style: for example both are better than stock at high rpms bit you ecofriendky guys probably aren't reving the engine that high for long. So you want what will work best in the rpms you will use, while still performing better than the oem setup

[petrified.rabbit]

The factory has improved the oem intakes in performance applications. But the stock aveo intake is very restrictive in design, while it will have a large gain over oem with a drop in, replacing the system will open it up and help it breath for better throttle response as well as hp. The aveo stock muffler is just as restrictive as the intake replacing both to match improves performance as well, but your talking top end breathablity.

[ontarian_frog]

In most testing on car engines, 99% of the performance benfit can be made through just a drop in K&N filter.

The rest is bling.

Wrong. The factory filter has close to 0 restriction. The design of the intake is responsible for the restriction. A short ram intake would be better for gas mileage. The engine will breath in warm air and will need to open the throttle body more and by doing so, improving Brake Specific Fuel Consumption.

See http://autospeed.com/A_111486/cms/article.html

Contrary to popular belief, opening the throttle body more will not necessarily mean burning more fuel. At cruising speeds, the ECU operates in closed loop mode and monitors the A/F ratio and adjusts the amount of fuel delivered by the injectors. Since warm air is less dense, the throttle body needs to be open more to let the same amount of oxygen enter. This lets the engine operate more efficiently (by reducing pumping losses) and gives better gas mileage.

Visit any hypermiling website and the advice is to put a warm air intake on the vehicle. It's bad for horsepower, but good for getting better mpgs.

[ontarian_frog]

1. Even if the air filter was restrictive, it wouldn't affect mileage as pointed out by this study:
http://www.fueleconomy.gov/feg/pdfs/...02_26_2009.pdf

If your are too lazy here is part of the conclusion:

[...]Results show that clogging the air filter has no significant effect on the fuel economy of the newer
vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control
systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel
consumption was not increased.[...]

2. Read articles where people actually measure intake restrictions
http://autospeed.com/cms/A_109217/article.html

In another article: http://autospeed.com/cms/A_1361/article.html
"Oh, you might also be contemplating dropping an aftermarket filter insert into your airbox. Chances are you won't gain a thing; based on our previous intake testing, the standard filter element in an un-touched intake system is responsible for only around 3 percent of the total restriction. A drop-in replacement won't make any noticeable difference."

3. http://autospeed.com/cms/A_111396/article.html This article explains that although an aftermarket filter does have to potential to flow more air, the stock filter doesn't pose a restriction because it can flow more than enough air. It's like this: if the engine needs 400 cfm of air and the stock filter can flow 500, then the filter is not restrictive. So if you put a filter that can flow 800 cfm, the engine still only needs 400 cfm.

4. To quote this one: "http://autospeed.com/cms/A_111486/article.html
"To put it as simply as possible, there’s no problem with the flow of the factory filter – even when it’s dirty. [...]Don’t start off by changing the filter; start off by altering the intake flow into the box.

If you've taken a look at the Aveo's intake, the snorkel is pointing backwards in the top of inner fender. Therefore the air has to make a 180 turn into the airbox before reaching the engine. And that turn is not a"smooth bend in a pipe".

[Unidentifiable]

Where on the Aveo are you seein this terrible restriction. Is it the tube going from the intake to the assembly which has a 30 degree slight bend to it?

1. The OE designed air filter flows enough air to support the engine at or near redline with 100% throttle. Many of K&N's reports of improvements in power cannot be substantiated when tested by a third party. Also, their "tests" which compare drop-ins and FIPK's to the stock configurations don't contain enough data or data points to be considered conclusive. Regardless of the last point, it's not in your best interests to believe the company trying to sell you something exclusively.

2. Flow through a pipe with ANY bend is restricted by the bend. It takes energy to make that curve, which slows down the airflow, which then causes a restriction in the pipe. It's not the pipe itself that causes the restriction, it's the flow in the pipe losing energy.

3. A pipe's cross-section is not it's total flow area. A boundary layer builds as air flows, which effectively reduces the usable cross-section of the pipe. Include the boundary layer into the curved section, and you start to see that any bend, even the relatively calm ones in the intake tract of most cars, is a significant restriction to flow with high velocity and flow demands.

4. When discussing concepts which not everyone may understand, it is helpful to post links to resources which might explain or properly convey your points. There will be less misunderstanding, and it helps others to learn and determine which points are valid and applicable to them.

Please try to remember that lurkers are always reading these posts, as well.

Boundary layer within a pipe - Boundary Layers (See point #4 on this page)

Air Filter effect on fuel economy - EPA study posted earlier in this thread.

Bend restrictions - Abstract - "On the effect of a sharp bend in a fully developed turbulent pipe-flow.

Bend restrictions, engineering calculator - Pipe Bends and Thrust Block Forces

[petrified.rabbit]

Heres a comparison of a few intakes.

http://www.mustang50magazine.com/techar ... irbox.html