What is an induction kit?

What is an induction kit?


     We repeatedly have been asked questions such as - what is an air intake, or as we call it - an induction kit? And why GSR induction kits are so special? Oh, and let's not forget comments like "overpriced plain silicone hose"...
     Usually, people refer to or like to call a plain cone filter an "induction kit". But it's not. Actually, it's nowhere near an induction kit. It's just a filter. An induction kit is much more than that.
Chinese induction kit 
     Most cars have air filters fitted in an enclosed air box. The majority of these filter elements are made from paper, which filters out dust particles from the air and prevents these from getting into the engine.
     When it comes to filtration, paper is the best filtering media but with a sacrifice for air flow. It is also the cheapest media out of all used in the industry. To make things worse, air boxes are designed to reduce the noise of the engine and therefore have various vanes and angles cut to maximize noise reduction by the cost of performance. Although by now you may have gotten the idea why manufacturers use paper filters enclosed in complex air boxes, we still would like to highlight some main key points:

1) Price - out of all (paper, cotton gauze, foam, stainless steel mesh) medias, paper is the cheapest. Save a fraction of a cost here and you'll save a million over the long run.
2) Filtration - since manufacturers have to make their products "dummy proof", or in other words suitable for all weather and terrain conditions, they have to make sure that the engine won't choke with dust when driven on a highly dusty gravel road day by day. Naturally, an open cone type cotton gauze or stainless steel mesh filter won't provide such high level of filtration as paper does.
3) Noise - as already mentioned above, not everyone likes to hear their engines, so manufacturers do all sorts of tricks to reduce the induction and exhaust noise levels.
4) Water ingestion - again, the term "dummy proof" comes to our mind - the intake is made so complex to eliminate the possibility of slight water ingestion in case the driver does not apply common sense when driving through a flooded area.
     Because of all this, the air flow is very restricted through the whole system and of course there is potentially a loss of power due to turbulence caused by all the safety measures implemented. To make up for the power loss, some manufacturers make the air filter surface area a lot larger than the intake tubes in order to close the gap between noise reduction and performance. But these cases are very rare and seen less and less often on new modern cars.
     When it comes to car tuning, noise reduction is generally the last thing on peoples mind. Swapping the restrictive air box with an open cone filter helps to improve air flow into the engine and releases the induction roar, a noise associated with tuners cars over the world.
     Next comes the filtration question. We won't go deep into explanations about how different filters do their magic (there are a number of sources on the web), but we can simply divide the four main types of filters for you to understand easier:

1) Paper - best filtering and most restrictive.
2) Foam - great filtering, less restrictive.
3) Cotton gauze - average filtering, least restrictive.
4) Stainless steel mesh - no filtering, but no restriction as well. Basically, it just helps you to keep the leafs and other large objects from entering your intake system. 
     It would appear, that performance air filters are a win/win situation for tuners, however, there is a downside when used incorrectly.
     Most drivers remove the OE air boxes and install the open cone filters right in their places. Most of the time those areas are located in the warm engine bay and therefore filters will suck in warm air, which carries less oxygen.

     In most cases this results in loss of power... Thankfully, after a mile or so, the air temperature in the engine bay is reduced closer to ambient temperatures due to ventilation, but still you may be facing this hot air issue, especially on the more powerful and larger engines fitted into tight engine bays.

     A solution would be to draw fresh and cold air directly into the air filter. This is usually achieved by either a so called cold air feed pipe, or (much better) by positioning the cone into a colder spot in the engine bay (if there is one). If space allows, the last solution is an ideal one for your precious ride, except some things that most of the DIYers tend to forget. Let's review some of the "great" ideas found while doing a quick google search:

Angled induction kit PVC intake

Intake Intake2

     You should have gotten the idea, what is wrong here. If not - just continue reading, as we will explain it below.
     Turbulence - a funny word that is also known as the main air flow enemy. At least when designing air intakes...
     You could try and read the description of this definition in wikipedia, but we doubt that you'll understand it, unless you're a scientist. So we decided to explain it in a more simple way: imagine a gulp of air as a tennis ball. If you throw it somewhere and it accidentally hits an object in it's way - it starts to bounce all over the place and eventually, lands somewhere where you didn't want it to land. Well it's the same story with air, just that because it travels cramped in a large pack (imagine a thousand tennis balls all thrown in the same direction and only one bouncing around), despite jumping around and loosing speed, it swirls around but eventually travels in the same direction, just much much slower than it should. Below is an example on how air travels when it meets an object, in this case a mountain:

     Note that only the top paths still remain straight. The closer to the object, the more swirls air makes. Each swirl creates friction and reduces speed. Furthermore, turbulence is accumulative. This means that the more objects air will meet in it's way, the more swirls we'll have. Now go back and take a look at those intake solutions you've seen earlier. See how many joints and different diameter connections are there? Well, every single connection has an edge that works in a same way like that mountain shown above. Where such intake removed restrictions to air flow by replacing the OE air box, it restricted it again by making the air turbulent and slow again.

     Now, we come to the part of explaining the "magic" behind the GSR induction kits.
1) Where possible, we use a single hose that connects the air filter to the throttle body, even if it is over a meter (3ft) long!

Citroen C2 kit - 1.8m long!

     The special silicone hose is made as a single non disassembled hose that has no internal edges, connections (except for build in breather outlets where required)  or other objects which could cause turbulence. The internal side is made as smooth as possible to remove any restriction for the air fed into your engine and makes the complete hose virtually non turbulent at all. As an added benefit, silicone has another huge advantage over any metals used in competitor kits - a metal pipe, can not be installed onto the throttle body and the filter without the need for a silicone or rubber connector. This means that you already end up with at least two joints and internal edges of added turbulence in your kit. Furthermore, silicone is flexible. Which means that you can flex, twist or bend it the way you need when installing in those difficult and tight engine bays, whereas with aluminium or stainless pipes, in most cases you again end up with a spilt in the pipe and the na silicone or rubber connection, which again adds that no good turbulence...

2) Next, another very important feature of GSR induction kits is the extensive use of Venturi principle:


     The two above images show a theory and reality of the Venturi effect principle. The image on the left shows what happens to the velocity (speed) of fluid (or in our case air), when you smoothly reduce the diameter of the pipe in which it flows. When you have a standard air filter inlet, smoothly reduce the diameter of the pipe up to a required size (point number 3 - read below) and then smoothly increase it again to the size of your throttle body internals. And you have a pipe that not only has very laminar (smooth) air intake that has a minimum drag and speeds up the incoming air. All of this can be described as a small charging effect added to your normally aspirated engine!
3) Last but not least - fine tuning of the engine RPMs. We already mentioned that by applying the Venturi principle we reduce the hose size to the required one for optimum air flow speed increase. But how do we know how much does a hose needs to be reduced? And based on what do we do the calculations?Well it's easy! Again, most of the competitor induction kits offer significant
 power gains in the highest RPM range. However low end power and torque can be compromised. In small naturally aspirated engines the effect of an induction kit is often a noticeable loss of low end power. This is fine if you want to use the top end of the RPM range all the time, like you would in a race environment, but on the street this is just not viable, thus fuel consumption would be much higher.
     That is why GSR induction kits made their name among the small, naturally aspirated car enthusiasts such as FIAT, CITROEN, FORD etc. owners. The key point of GSR designed kits is that they are more than conventional Cold air intakes. We use some basic formulas of physics to calculate the required amounts of air for the given engine and after we have found the optimal hose routing through the engine bay, we apply the calculations in order to find the correct intake size for optimum mid RPM range. Our main priority is to boost the torque in the mid RPM's. Most competitors claim top end power gains, while we sacrifice these for torque, that actually drives your car off the starting line. Plus, when you have the most available amount of it in mid RPM's - you'll be using this benefit most of the time on your daily basis!
     An added benefit, which most people seem not to be aware off, is that the GSR air intake revisions actually aid fuel consumption. By aiding the air to enter the engine and making a little charge along the way, there is not only more bottom end torque created, but because of that the engine has less power to use to achieve the same torque and in turn uses less fuel to do that. Just don’t get carried away, as in most cases the improved sound provokes more aggressive driving, which in turn, most likely will equalize the fuel consumption gains. But if driven same as previously the initial price of the GSR induction kit will be melted the more you drive your car.

     Unfortunately, it's a bit different on Turbo cars. You can not fully exploit the Venturi effect on a turbo car, because the turbo draws the air in at a much higher rate that it would even flow on it's own. But that's ok, because for the turbo applications, we design our kits to be the least restrictive and to help the turbo draw in the required air easier.
     Another modern enemy in today's cars is the Air Flow Meter (AFM) or Mass Air Flow meter (MAF). On the older vehicles you could just remove it from it's tube housing and install it in a convenient place into a specially shaped opening in the silicone hose. But on more modern cars, the ECU is tuned in such a sensitive way, that the air flow meter can not be moved out of it's original location. You see, the particular location has it's own heat range. The ECU is setup in such a way, that it knows that your MAF can only face certain temperature ranges that will occur in that place. If you move the MAF to a colder place in your engine bay, you will have trouble, because even if you have the same air amount entering your engine, the MAF will see that air as colder and thus thinking that is faster = more of it. This will result in your ECU adding some extra fuel into the mixture, without a real need. This will result in worse MPG and in some cases even will illuminate the Check engine light. To avoid this, we keep the MAF in it's original location, which often restricts our air intake design abilities.

     Ah, and finally, let's not forget, that the modern ECU needs some time to adapt to changes made in the engine bay. 
They will auto calibrate the fuel mixture based on lambda readings. But this may need some time. So the full benefit of the new kit may not be always felt instantly. In some cases it is advisable to reset the ECU or just to drive around for a while, say until one tank of fuel is used. So don't panic if you've just installed your new induction kit and instantly done a dyno test which shows only a small power gain. You may need to drive around in town first, to bed in the ECU and only then can to the dyno run. Below you'll find a dyno graph of a same car (a small Fiat) that was put on a dyno straight after an intake upgrade. Notice the different power output on subsequent runs. The tendency was that every subsequent run showed a higher output than the previous one until eventually the ECU adapted for the changes and only then we have seen the car starting to slightly drop it's output on the last few runs (due to the increase in temperatures, transmission oil viscosity etc):ECU adaptation
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