slats

Sorry for a newbie kinda question (although I am a senior member) but I don't know a whole lot about aftermarket mods. Here are my questions:

1. I know that adding an intake will give you extra hp because the engine will breath better. Some people tell me that they increase fuel economy....is this true? Have any of you checked to see how many mpg before and after?

2. Also, if an engine is getting more air it will have to use more fuel. Won't this make the engine run rich and use more gas? Will adding an intake cause put more wear on an engine?

3. What is the difference between a regular intake and a "cold air" intake? How do they work?

4. Now on to exhaust.. Everyone is always putting these huge soup can sized exhaust on their cars and talking about reducing backpressure. Does this save gas or use more? Also, isn't it true that you can have too little back pressure with a 4? If so, how do you know what the optimal amount is?

Thanks for any help!

Slats

tsXgtp

A cold air intake usually bends the filter down in the fender area to seal it off from the warm engine.
The intake will put more wear on an engine because of the lack of filtration with the cones.
Too little back pressure will rob a lot of torque from an engine and backfire Probably will kill mpg's.

xizor

1) there is another thread that asked the same question. answer was inconclusive, as it makes your car more effecient but those who have it will probably mash the throttle more to hear it nullifying the effect.

2) your ecu will slightly compensate the correct amount of fuel for the air. you will not run more rich, rich doesn't mean more gas, it means more gas than you have air. they should stay in the same ratio more or less. and no, it does not put more wear on the engine, it should really put less since it makes it easier to breathe. i don't know what tsXgtp is talking about the filter, its a K&N, its probably better than the stock one.

3) the stock intake/resonator use some tubes that twist around to keep it quiet. the cold air intake uses a straight tube w/ a bend in it to suck in air. air can flow faster, and at higher velocity.

503TSX

xizor has hit the intake question on the nose..(from what I know) .. Think about it this way, if you had to inhale through a 1/2" straw or a 1/4" straw, which would you get tired of first? which would take more energy to draw air in?.... that is the reference that I always make with intake and exhaust...

Just be aware, that the freer flowing intake filter along with it's nice high velocity charge tends to alter your vacuum system in the car especially at WOT. We are not talking about a huge difference in any way, but a small one, and it will affect your brake booster, and more importantly, your fuel pressure regulator, which is a basic diaphram/spring/vacuum setup where at lower vacuum, your fuel pressure will drop, while at higher vacuum fuel pressure will rise... of course, I don't think this has any effect on the TSX or any of the K-series engines...

Exhaust ... yup. it is possible to have too little backpressure, as the back pressure causes a "scavenging effect" on the cylinders under low rpms, allowing most of the exhaust gas to get sucked out... if you have too little back pressure, you don't evacuate as much of the exhaust, and end up reburning some of the exhaust, thereby losing torque, and running a little rich sometimes. Of course, when it comes to HP(high rpm) you want the freest flowing system posslble... Generally speaking, you can get one, or the other, but have to generally settle for something in between... one of the best pieces I have yet seen is a butterfly valve that sat aft of the catalytic converter, and closed during low idle(creating backpressure) and opened during WOT, helping with the HP... unfortunately, when you shifted, or dropped rpm's fairly quickly, over time you could hear the valve hitting it's stop in the exhaust... the oil/lube on the valve apparently didn't react well with the exhaust fumes...

tsXgtp

When it comes to filtration, paper is better. K&N gets better flow and more air at the expense of filtration. If you do (or read) oil analysis' from before and after effects of a cai, you'll see especially higher contaminant levels across the board (lead, silicon, copper...).
Check out www.bobistheoilguy.com. Its a pretty useful site. They have a great write up on filtration tests.

LaxTSX

This doesn't really answer your question, but i thought it might be useful for you if yoru getting an intake.

I had bought an Injen intake and had it installed for approximately 3 months. I found that the noise level to be annoying at times without that much noticable gain. So I decided to put back the OEM intake and was very surprised at what it felt like.

The main difference was of course the noise, but it was also smoother. The intake cause alot of rattles to pop up when you smash the gas, and I did that alot. I didn't realize that the intake cause that much vibration. I don't think I'll go back to the intake. Its just my thoughts. The noise sounds good though. I like it at times, but just not all the time.

xizor

something is wrong w/ your intake, another member had a rattling problem w/ theirs too.

a correctly installed intake will make 0 noise unless you are at full throttle. i can drive my car without ever noticing the sound if I choose to. others will agree, it shouldn't be causing vibration.

slats

So what's the bottom line then? Which intake style is better, short ram or cold air? And what about fuel economy w/ an intake? Better or worse? Thanks

Slats

xizor

well if you buy an injen or K&N, they can be either a short ram or cold air out of the box. your fuel economy wont be worse is all I can say, no scientific evidence though.

slats

Is it true that you can hear the intake sucking air? If so, that is cooool! Almost as cool as the sound of a turbo kicking in.

Slats

LaxTSX

yup ... I think it sounds sooo sweet when you hear that sucking ...