Hot answers tagged

17

Lean ≠ More Air I believe the source of the misunderstanding is in how the term "lean" is being interpreted. A lean mixture doesn't indicate the presence of more air. It indicates the presence of a higher proportion of air compared to fuel (air-fuel ratio, or AFR). Quick example Mixture A has 1,000 g of air, 80 g of fuel. AFR = 1000/80 = 12.5 ...


14

Does this mod ever give a measurable increase in power? tl;dr: yes, sometimes it works well. But... Your picture is a good illustration of some of the problems with just saying "cold air intake" and expecting that to mean the same thing to all people. Let's break down the pieces of the puzzle and talk about how those might help or hurt: Filter: ...


8

The point is to feel like you've done something cool to your car and freed it from the shackles of The Man/the OEM intake. The primary benefit of Cold Air Intakes is to the bank account of the kit manufacturer, the secondary benefit is your car making a nicer noise, if you like the sound of an aftermarket intake. There's been a few debunkings of CAIs over ...


8

It's not that the catalytic converter can't handle more air per se, it's that running lean increases the temperature of combustion (I actually don't know why, but now I'm curious) and the catalytic converter needs to run inside it's chemical operating range. Something to do with the chemistry that I also don't know. As for advantages for turbo boost and ...


7

Variable-length intakes increase the pressure of the air entering the intake manifold thanks to a physical phenomenon called Helmholtz resonance. It's also known as dynamic supercharging since it avoids the use of a mechanical device (compressor/blower) to boost intake air pressure. How the Helmholtz does it increase air pressure? Without getting too ...


7

Normally the idea is to get more air into the engine using a less restrictive air filter. As an engine is basically an air pump, getting more oxygen and more fuel into the engine usually equals a bigger bang and thus hopefully more power. That said, in order to get a meaningful improvement using a performance air filter, the main restriction needs to be the ...


7

It depends. Just because an intake can flow more air mass doesn't guarantee that the engine will utilize it. The intake is part of a system of components. The engine produces power by managing air flow into and out of the combustion chamber. There are usually other actors involved: Intake side. Carburetors, throttle bodies, intake manifolds, intake ...


6

Lean operation vs exhaust catalysts: The three-way catalytic converter fitted to gasoline vehicles can't operate under lean engine conditions because the reaction of NOx to nitrogen and oxygen is a reduction reaction, and for this to occur there needs to be a corresponding oxidation. In the three-way catalyst that is the oxidation of CO and hydrocarbons to ...


6

The 'floating' intake runners are moved by a mechanism, coupling and decoupling them from the main intake runners to increase the overall length for better low RPM performance. This process was recently discussed here: mech.SE on inlet runner length I don't see that having the extension pieces in the decoupled position would have any effect of the resonant ...


5

tl;dr: your car will be more vulnerable to hydrolock. Don't use full throttle in deep puddles. In the rain, you should be fine in most situations. All that said, you'll still be able to ruin your car if you try hard enough. If you submerge a running car in water, it's going to damage the engine, cold-air intake or not. One of the worst possible ...


5

First of all by "most production motorcycles" I am assuming commuter level motorcycles used in South and South East Asia its not true that all production motorcycles have intakes facing backwards, its more or less a ergonomics based design decision , some motorcycles have intakes facing 90 degrees to the side. Some have them facing towards the back as you ...


5

MAP = Manifold absolute pressure and is a sensor to measure vacuum, the computer calculates the engine air flow based on the vacuum, throttle position, and intake air temperature. The computer also measures the barometric pressure using the MAP sensor before the engine cranks, this lets the computer compensate for altitude, or how dense the air is. Typical ...


5

It sounds as though you did suck up some water and were on the verge of hydrolock, but didn't quite get there. I also doubt you have caused any damage to the engine, in fact, you may have inadvertently helped your engine (though I wouldn't suggest you do this again!!!). The extra sputtering may have been a case of the filter on your CAI getting soaked with ...


5

The oil stuff is more than likely caused from what the intake pulls out of the crank case through the PCV. If you can get a hold of a couple cans of Seafoam, this should take care of the residue about as easy as you can do it without taking the engine apart. Use the rubber hose to the right of the photo to introduce it into your system. As an engine gets ...


5

Specifically a foam filter for a lawn mower needs oiled, but just lightly. A foam filter lacks the ability to stop small particles as compared to a paper filter. The oil is added to make the filter "sticky" to these small particles giving the foam filter better filtering capability. As far as major engine damage, probably not. Worst case scenario the engine ...


5

The length of the intake runners have certain affects on the engine operation. For example, longer intake runners are used to improve the bottom end torque (torque at low RPMs) while shorter intake runners will improve top end power (horsepower at high RPMs). The lengths will vary from engine to engine as well as what the goals of each vehicle the engine ...


5

If the prints are just on the seal, I wouldn't worry about it. You could possibly take some gentle cleaner (Windex or Formula 409 or the like which will clean grease) and make it pretty again. It won't, however, decrease the function of the filter in any way. If they got a bunch of oil on the element itself, you might want to think about it. Really nothing ...


5

A few things to consider if you end up doing this: A longer shaft will reduce the speed that you can safely spin the turbos up to It's got to do with something engineers call rotordynamics, although I highly doubt you would need to spin something up to 125,000 RPM for a turbojet application :) You may also find that the existing journal bearings are not ...


4

The manual you linked to explains what they're used for. The AACV is the main idle speed control while the FICD is used to supply additional air to the engine when the AC is turned on. AACV (Page EC-GA-117) This system automatically controls engine idle speed to a specified level. Idle speed is controlled through fine adjustment of the amount of ...


4

Would there be a substantial enough of a horsepower boost to be noticeable? The most you could see from such a modification is 15hp. This would not be enough for the seat dyno to register, unless there are plenty of hemorrhoids to detect it. More then likely you'd see a measly 5-10hp, and then only at the higher RPM levels would this be apparent. You ...


4

Almost never? Mainly because they're really a 'hot air intake system'. This is especially true for cars using forced injection due to the high under-hood temperatures. If you want to reduce intake restriction look into a less restrictive 'panel' filter like a K&N. Even then, it really only matters if your car is intake (vs exhaust) limited and your ECU ...


3

A quick search appears to indicate that this is a common issue on this particular model of Civic. The bolt does not want to come out all the way because the heat from the engine over time has liberated the plastic female housing that it threads into. To remove it you need to figure out a way to keep the plastic from spinning when the bolt is turned, as per ...


3

The idle air control valve is integrated into the throttle body unit as shown here: It may not look exactly like that, there was an update some time around then but the parts are very similar and the principles are the same. There is a forum thread with a few more pictures of the cleaning process here: ...


3

Two things come to mind here: First, cars are a sieve. There are more holes in them than you can shake a stick at. Lizards are very pliable creatures and can fit through any of these small openings if it fits their needs. Second, the lizard may have been in your car since the last time you were in your car. You never know.


3

It doesn't sound like a fuel line problem ( though there's a small small chance it's a fuel pump ), it sounds like your engine isn't getting enough air on one end or the other. It might be a dirty air filter, or it might be a clogged cat or bad O2 sensor. Sometimes it's easy to tell if the cat is clogged, it will get extra hot and turn red and that's your ...


3

Typically it's to catch the blow-by. While the PCV system is designed to vent just air/fumes as Nick C mentions, as an engine wears it'll start to blow some liquid oil past. That's normally redirected to the intake so it'll burn off (as oppposed to just dripping it on the ground like the old cars used to). Car enthusiasts like to install catch cans (that ...


3

Doesn't it suck up only as much as engine speed and throttle position allows? No, throttle position and engine load determine the quantity of air consumed. It can be quite hard to understand at first how a naturally-aspirated engine can ingest different quantities of air at the same RPM. Here's what the Engine Management Fundamentals chapter of the ...


3

The reason to use two is a matter of scale. Fast idle requires a high volume of air but the exact amount is not critical. So a big bore with a cheap slow moving plunger is all that is needed. Idle requires a much smaller amount of air but a much higher degree of control than fast idle. A more expensive fast cycling shutter valve is the most common design. ...


3

The working cycle of an 4 stroke internal combustion engine is like: (1) Inlet of the fresh air (2) Compression (3) Working Cycle - expansion (4) Exhaust Cooler intake air is especially beneficial for part (1). Since cooler air has a higher density, it means that the gas velocities at the inlet are lower. Therefore lower pressure losses at the cylinder. ...


3

I didn't see anyone mention it but I believe any increase in power would only be at wide-open throttle (WOT). So if you are racing or really aggressively pulling away from stop lights or accelerating, maybe it helps. Day-to-day driving at less than WOT the engine management system will keep the air-fuel ratio at an acceptable value. If it doesn't get enough ...



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