Acura TSX Air Intake Guide

Shopping for an aftermarket air intake can be confusing. You'll see words like JDM, Type-R, Type-S, V2, Bypass Valves, Short Ram, SRS, Cold Air, CAI, Air Fusion, Turbo Air Filter, Ram Air, Tornado, Velocity Stack, Heat sheild, Ice Box, and maybe even some talk about Secret Weapons and Dragons...

The fact is, $60 or less may get you the most high performance air intake available!

DISCLAIMER: I am not an agent of any company. I am not here to advertise or sell anything. I do not have a degree in the science of air fusion, nor do I understand how polishing the outside of an aluminum air intake tube and putting a badge on it increases horsepower at the wheels. Everything you see here is the product of my own reading, observation, experience, and most importantly opinion. eBay, AEM, Comptech, and Acura are registered trademarks. Any references to, or statements regarding the products advertised, manufactured and/or sold by these or any other vendors may be completely inaccurate as they represent the opinions and interpretations of just one human being, whose personal experience may be different from that of all others.


Why install an aftermarket air intake?

The power is nice, and the noise is nicer! But the main reason I was looking to install an air intake is fuel economy. My experience is that having a short ram style air intake can increase fuel economy on the order of 1-2mpg in everday driving and 2-3mpg on the highway. In my case, I'm talking about high-tech small displacement 4cyl engines, so this increase is not even 10%. Even so, at $3/gallon, averaging 30mpg in my TSX, every mile saved is worth about 10cents. How many thousand miles a year do you drive? It's a no-brainer!

But it's a performance mod isn't it? Where does the power come from?

The performance gains are a result of helping the engine to run more efficiently. Near redline, the engine is pumping in almost 600CFM of air, which requires power from the engine to do. After power is released during the combusion cycle, some of it is lost forcing the exhaust gasses through the rest of the exhaust system. This and other "breather" mods like headers, high-flow catalytic converters and cat-back exhaust systems increase the efficiency of the engine in a similar way. The power output you see on a dyno is what's left after after the engine overcomes many losses, the restriction of the air intake, exhaust system, and transmission just to name a few. Its important to understand that the stock setup of any car is the product of many compromises. If nobody cared how loud the intake or exhaust were and there were no emission standards the stock engine might be perfect for racers. A higher-flow exhause or intake will do a better job of cutting those losses, but it will certainly not be as quiet as the stock parts.


I recently broke 30k on my '04 Acura TSX and decided it was time to start doing some mods. My last 2 cars were a '93 Integra and an '03 RSX. In both cars, I was very happy with the results of installing an air intake. The Integra got a ~$30 short ram air intake purchased on eBay, and the RSX got than AEM Short Ram. Not much in the way of differences to be found, except that the eBay kit supported the air filter by a bendable metal strip that the hose clamp on the air filter secured, while the AEM kit actually welded a little bracket off the side of the pipe so that you could secure it to the frame reusing one of the air box mounting screws.

This time around, I did a little more reading up before I purchased anything. With all the reviews, advertising and claims of scientific research going into the design of these things, it's certainly a little difficult to cut through all the BS. Here's what I took away from the situation:

  • While there are differences, there is not aftermarket air intake that greatly out performs all the rest.
  • The bigger name brands have more advertising costs that get divided over the number of systems sold.
  • A common selling point is scientific research and testing.
  • My generic intake bought on ebay and name brand had no fabrication differences that would have an effect on performance.

    The "science" of it all can be summed up quite simply: LOWER THE AIR INTAKE RESISTANCE, AND DRAW IN COOLER AIR IF POSSIBLE.

    This is where Short Ram vs. Cold Air go in different directions to improve performance...

    So what is it that you want to improve? If you're not putting the car on a track regularly, and don't find yourself driving the car in the upper part of the RPM range most of the time you're in the car, then seriously consider a Short Ram. You will see the biggest improvements in the low- and mid-range areas, where most of us tend to keep the engine during the majority of our driving. The Cold Air systems sell on the basis of a higher PEAK horsepower number, which it attains from getting cooler air drawn through a longer (and therefore more resistive) length of pipe. You don't see the benefit of drawing cooler, denser air until the engine overcomes this added loss, which typically happens at higher RPM's. Considering the risk of drawing rain water into the engine during driving and/or messing around with bypass valves, and it's too much hassle (*in my opinion) for cars that are going to spend most of their time on the street.

    Back to the Short Ram System (SRS). What we're looking for here is a reduction in resistance. The two most common ways of accomplishing this are:

    Lowering the resistance of the intake tube

  • Using a smoother material on the inside of the tube, polishing a metal tube, etc...
  • Shortening the length of the tube, if possible
  • Increasing the diameter
  • Increasing the radius of bends

    Lowering the resistance of the air filter

  • Using a filter material that flows better (usually cotton or foam to replace paper)
  • Increasing filter surface area

    With this in mind, let's look at the two options I considered:

    AEM Short Ram System (SRS)Comptech Ice Box
    Replaces everything from the Throttle Body on.Replaces airbox and adds trumpet-shaped tube, presumably to smooth the air taken in, maybe to draw from a cooler area?
    Aluminum Intake Tube, choice of colors or polishedStock intake tube is used
    Washable cotton filterWashable foam filter
    * * * Both yeild nearly identical results on the dyno!!! * * *

    So now, let's take a look at what we have to work with. A call to AEM Tech Support said it all! I asked if they had ever measured the air velocities inside the pipe. The response was "It's irrelevant." So I indicated that I thought it was, citing future mods to my car. Apparently the intake is "designed with future mods in mind" without even knowing what they are going to be! How is that even possible? Is this intake so well-designed that it knows the future? Or is it just universally awesome and pre-tuned to all possible mods, making the mod type, perhaps even the vehicle itself "irrelevant" too!?!? That would explain why the kits for nearly every vehicle look so similar, and that a constant-diameter aluminum pipe is the ideal solution for any engine, of any displacement, etc, etc, etc... I would've felt alot better about the phone call had the guy at least been able to send me some installation instructions. You can download them in .pdf format from most manufacturers. All they had was a word .doc that was too big to email, which didn't even have a picture of the final installation. I was told by this tech that if I want to see a picture of how it looks installed, I should go on some Acura-related websites and find one, right before he hung up.

    Needless to say, I was not anticipating and decent support if I were to buy from AEM, and more importantly, any ideas of scientific research, tuning, etc, just went all out the window!

    If you dump the cash on the AEM, you're paying for all their advertising cost and hype! They are selling aluminum tubing bends that are comprable to what you can buy on eBay for a small fraction of the cost! Plus, they have someone like I spoke to on payroll to provide "technical support".... Ok, so you can get a powder coated tube from there, some badges, and a real showy look. SO WHAT! I don't know about you, but I drive and park my car with the hood closed. I open it for service, and don't really pop the hood to show people what my engine comparment looks like. So with people like me in mind, there are AEM stickers I can put on my car, and if I dont want to stick anything to the vehicle, then why not bolt on the AEM license plate frame, so everyone can know I have money to burn!!!

    The stock intake tube, even attached to an airbox and an air smoothing device, still made equivalent power in the Comptech Icebox application. I like that idea! The stock tube has a GRADUAL TAPER, similiar to that of the trumpet-shaped velocity stacks, etc, that do a sort of "impedence match" between outside air and the throttle body. Sounds alot better than having a constant diameter tube, and then snagging air on a reducer! PLUS, the stock air intake tube opens up to a 3.5" ID!!!

    From both applications of nearly identical performance, the one thing that's clear is that the stock resonator and paper air filter have to go!

    Now, the Comptech Icebox dyno results tell us you can use the stock intake tube and get comparable results to the AEM Short Ram System. That tells me the intake tube is not the problem. Take a good look at it. It goes over the throttle body, and the ID tapers up to 3.5" ID. Not to mention, its extrememly short! Not much to do in terms of taking off excess legnth of intake tube, and as far as smoothness, the bends are more gradual than that of the AEM Short Ram System. Why wouldn't AEM tell you to just use the stock intake tube? They would be stuck trying to sell a washable cone filter and sticker kit for a Minimum Sugested Ridiculous Price (MSRP) of $329! So rather than using a 3" pipe with sharper bends and a 3" cone filter, I say:


    Do-It-Yourself Short Ram Intake Mod for the Acura TSX!  Same performance as many name brand systems out there for about $60!

    I walked right into PepBoys near me, and found a K&N Cone Filter with a 3.5" inlet and a considerable larger size than what comes with the AEM kit for under $60 right on the shelf! Once you remove the airbox, you will see that there is a slight bend required to attach a cone filter to the end of the stock intake tube without bending it. I picked that up and headed over to Home Depot next. I cut about 20-25 out of the middle of a PVC drain pipe bend. The OD of the pipe was pretty close to 3.5", so the stock intake tube and and K&N filter clamped over it beautifully!

    So there you have it! A $60 Short Ram System you can build with everyday parts!

    Observations were as follows:
  • Noticeable Increase in Throttle Response
  • Increase in Air Intake Noise as RPM Increase
  • Feels like it pulls a little harder during Acceloration
  • Gas mileasge increased from approximately 30-31mpg up to 32

    Overall, the same effects of installing air intakes in my previous 2 Acura's were observed here. Total spending was under $60, and installation time investment was under 1.5 hours including the drive to PepBoys and Home Depot. I would recommend this to anyone, as it just makes the most sense in terms of time and money.

    Enjoy modding?

    Click here to read about an interesting short shifter project...