A True Approach To Adding a Cold Air Intake To A Saturn
Like many Saturn owners, I feel there isn't a whole lot in the way of DIYing
modifications when it comes to instructions (especially for our cars). That said, this guide will explain
exactly how a true cold air intake works and how to add one to your car in a very
inexpensive manner. The purpose of this is to get truly cold air (air from outside the engine bay)
to the engine without "heatsoak" to provide maximum performance.
I would first like to mention that this idea came from a person who did this on their
Scion. I would like to give my credit to this person here
for the inspiration to do it to my Saturn. He is the one that has done the hard work of testing and research
and I am just applying my version to my Saturn. Before going on I encourage you to read that post in that link so you understand what
I am trying to achieve here and I won't have to explain every item I put into the intake.
The car that I own and will being adding this DIY Cold Air Intake is a 2000 Saturn
SL2 with DOHC and an Automatic Transmission (if only it was manual!). I will be keeping track of expenses,
time and will provide video and pictures when available.
I didn't buy some fancy CAI or Ram Air Intake although that was my initial thought to putting an aftermarket
intake on my car. After reading the post that Dr. Isotope wrote (see my
link at the beginning of the page) I realized that these CAIs do not really provide cold air at all. They theoretically
sound good because they are not getting air from what would be the engine bay but they have a lot of disadvantages to them.
For one the longer tube may increase torque in the mid range but loses overall power because the air is not being forced
into the engine (think turbo and you understand the importance of forced induction). There is also the constant worry of
hydrolock (the process in which water gets into the intake and log flumes right into the throttle body and ultimately
into the engine, which is not what we want). With this DIY intake it virtually eliminates hydrolock and still protects the
incoming air from heat while it provides the shortest route to the engine.
This will be a 3 Stage process as outlined by Dr. Isotope. I will explain more about the stages later. Before anything happens
it is important to note the before effect of this intake. This way we can see the differences this intake will make (however, a lot
of the differences occur by feeling (i.e. throttle response and acceleration but I will do my best to note those changes in car performance).
Sound is one difference that you may hear if you listen closely.
The Before Model
My friend and I decided to test the car out before the CAI intake was installed. He placed a microphone under the hood and a camera on
the passenger side sun visor. You can hear and see what this experience is like in the following video. There are 4 points in which I mat it to the floor
and the last 3 are the ones that have the best sound quality in terms of acceleration and intake sound.
With about 30 seconds left in the video is the final flooring of the accelerator. At that point is when you can hear my automatic tranny drop two gears and accelerate.
This is important to note because after the intake is installed there is a difference in shifting believe it or not.
As you have read on the Scion forums (again, the link at the beginning of the page) Stage I includes getting cold air directly to the intake. This is how you are going
to "feed" your intake and engine truly cold air. Now on Saturns there are two fake grilles at the front of the body about 6-8 inches from the ground. It is essentially
where fog lights would go if you installed them. Now if you already have fog lights on your car you will have to find a different route to suck in cold air. The grille on the right side
of the car (driver side) is the grille that we are going to install a hose that will connect to the airbox. This hose will suck in air from the front of the car which is where
a wall of air will reside. This wall of air is key because it is forcing air into this tube with a high density and up into the airbox and intake and ultimately the engine. Not only is it forcing air into the intake
it is forcing the cold clean air into the intake which is our number one objective.
Now any hose will pretty much do. Three (3) feet of tubing is all you need. It should be 3 inches in diameter which will fit onto the airbox and compliment the rest of the intake which is 3 inches in diameter as well.
You can go to Lowe's or Home Depot and buy a dryer exhaust hose. However, I do not really recommend this because those hoses crush rather easily and we will be working in a tight area where the tube will be pushed on.
I bought a rather inexpensive air duct hose from a company called Spectre which sells parts for a DIY intake kit. I bought it off of Amazon for $7. Also we need to get a radiator clamp to clamp this hose onto the intake. You can get them
for less than $1 at Lowe's or Home Depot. Just check the plumbing section. It should be the 3" - 2 or 2 1/2" size. Meaning at full open it's 3" and when it's completely tight it's around 2".
So for a total of around $12.25 we can complete Stage I.
Now to install this hose. First, take out the fake grille on your Saturn. It pops out from the back. You may need to wiggle and play with it a bit to get it out. Now, from underneath the car push the one end of the hose
into the the grille opening and position it to come up towards the air box. The following pictures will demonstrate what I mean (click on the image to make it larger):
Now the other step it to thread it up to the airbox. This might be a little tricky since it is a tight space to maneuver. It took me about 10 or 15 minutes to finally get it up and connected at the snorkel.
Basically I came from the side to get up to the airbox, you'll notice there is a space to get it up there. It's right in front of the fuse box and to the right of the airbox. This also required a slight bit of modding on our part to get the hose to make the turn into the snorkel coming out of the air box.
You'll notice the air temperature sensor on this plastic snorkel so we cut the snorkel short and left a half inch to inch before the air temp sensor so we wouldn't have to move that. Then slip the hose onto the snorkel and clamp it. The following picture will again demonstrate this process:
Now back at the hose opening at the grill; you'll notice it's pretty snug in there and it looks secure. I'm not exactly positive how secure it is but I don't think it'll shift or move. If you feel like you want to do something about that, buy a nut and bolt and drill a tiny
hole into the body of the car and through the hose and afix it to the car.
That pretty much concludes Stage I. To check it out, start your car (check for any tools in the hood you might have forgotten to take out) and let it idle. Put your hand by the hose opening at the grille and you can feel the suction
of the air going into the intake. Now have someone rev it to 2,500 RPMs and it'll start to feel like a vacuum and it'll basically suck your hand into it. Now you know your car is getting cold outside air and not air from under the hood. This stage took me about 45 minutes to complete and wasn't all that hard.
So far we've spent about 12 bucks and 45 minutes.
Stage II is the simplest of them all. It requires you to remove the resonator and to put a high flow air filter in. The resonator just keeps your intake noise quieter. And to be honest it doesn't even do that really. Personally I think it's just a waste of plastic and space in your engine.
Taking it out will improve air flow to the filter and not waste it going through the resonator and will give your intake a growl in the upper range. On a SL2 the resonator is directly on top of the radiator and has a section going into the airbox. It's pretty hard to miss. It's in the red
rectangle in the following picture:
You'll notice a push pin at the front of the resonator (closer to the front of the car). Just take your key and gently lift it up until it pops out. Then slide the resonator out to the left and it's out.
Now all you have to do is plug the hole it leaves with a rubber stopper. The one I bought was a 2 1/2" rubber stopper. Again, stop into Lowe's or Home Depot and go to the Hardware section (right where you'll find your nuts and bolts)
and grab a stopper. Then just push it into the airbox and make sure it's secure. You really don't want it to fall out because it might damage something as your driving. I put a piece of duct tape over it as a temporary solution until
I'm able to get a rubber mallet or hammer and push it in further. There that was easy and it only cost another dollar or so.
As for filters, it's pretty much up to you and how much your willing to spend. But get rid of that paper stock one, it's restricting all that wondeful cold air now. I have a FRAM Air Hog (notice the orange filter in the pictures) in there for a year or so now so I didn't have to do
this part but for someone who still uses the stock air filter, it's time to change it. Mine was $20 with a $20 mail in rebate (crazy I know!). So essentially it was free. You can also go a bit higher end and get a K&N high performance filter
for the stock airbox. If you haven't noticed we are keeping the stock airbox since it is what will keep the cold air moving. A conical filter will be out in the open and be sucking air in from the engine, which defeats the purpose of all this.
Stage III is the most fun and really satisfies this entire project. This stage will be the most expensive (compared to the other two) but will not punch a hole in your wallet. It won't take too much time if done with calculated efforts and a little thinking.
This stage will be fabricating a "cold air" tube from the air box to the throttle body. We will be using Spectre (the company that the hose came from) to put this tube together. Spectre sells individual pieces such as 90, 45, 60, and 22 degree angle pieces,
straight pieces, and dozens of other pieces to custom build an intake. I will say that when I ordered the parts I had one configuration in mind but when I went to build the intake and fit it to my car I had to move pieces around so that it would fit. So it is
imporant to carefully calculate these pieces so you don't wind up building the wrong configuration.
Now before we go anywhere we need to find out what these pieces look like so we know what we can work with. Amazon sells these pieces relatively cheap (I bought them while on sale and got over 60% off each piece), but even at full price this shouldn't run you
more than $80. Now you may be thinking this is expensive but go shop for a "Cold Air Intake" that I demonstrated didn't do it's job. They easily run over $250 and $300. So for $80 your getting the true job of a cold air intake at a fraction of the price. Not to mention
you decide how it looks and where it will go. I tried to get the shortest route to the box and throttle body. You can just copy your stock intake configuration and you'll be fine but keep in mind it may not come out exactly like the stock one. Either way let's start shopping.
Spectre at Amazon will supply you with everything you need for this build (boots, couplers, pieces, adapters).
So that's where all this is going to come from (granted if you find another place that sells Spectre for the same or less than Amazon then go for it. I'm not endorsing Amazon (I actually don't prefer them)).
Now that we have the things we need it's time to take a look at building this. My intake looks like the following:
Based on that picture and some actual measuring, I figured my intake would require the following parts (using this as a rough estimate for what I would buy and how I would connect them in series):
As you can see I have some questioning points as to what should go in certain spots (ie the 22 Degree Angle or the Straight). As it turns out I went with the 22 degree angle (but wound up not needing it, keep reading to find out why).
So with that diagram and some measurements, I set off buying what I needed. I came up with the following list:
All of this came to $56.96 without shipping. Tack on another 5 dollars for standard shipping and for about $62 we have an intake tube (in pieces of course) heading our way.
Now when I received the pieces, I proceeded to build the intake in the manner and configuration I had thought of (except the vent adapter I put further down the line closer to the air box). However,
when I went to hold this up to my stock intake, it was about 2 inches too long and would requires some moderate modding of either my box or the route the tube was going to take. I figured since I have
so many pieces to play with I went ahead and reconfigured the tubing. I took out the 22 degree angle and was able to fit it then. So the order or building it (from throttle body to airbox) was: Reducer coupler -
90 angle - straight 6" - 45 angle - 45 angle - vacuum hose adapater - 45 angle - Coupler. That did the trick but it was a tight fit.
Since examining my configuration and one that would fit better I realized what is needed. Instead of 2 45's to make the turn, one 90 would make a better turn. Now you may be wondering why I didn't say 45+45=90 and just bought a 90. Obviously I understand that but it
wasn't a matter of angle. It was the length to angle ratio that was needed. From looking online it looked like a 90 angle piece would be short and make the turn too quickly. So being a little ingenuitive I figured two 45's would give me the right amount of turn in the
right distance. Obviously since installing it, I was proven wrong. It's not a huge deal since I was able to make due with what I had. But my point being here is that I have figured a new configuration for anyone willing to try to take this mod to their own car.
The new configuration would be: Reducer coupler - 90 angle - straight 6" - 90 angle - vacuum hose adapter - 22 angle - 45 angle - Coupler.
To me that would almost copy the stock intake exactly and fit right into that routing. Basically it came down to I thought the 90 degree angle was shorter in length. So now that I have made the mistake you don't have to. Now without further ado here is the new cold air intake installed on
So to wrap up Stage III the modified parts list can go one of two ways. You can either go with the configuration I got to work in my car or go with the new configuration I now think would fit better. Either way this is what you would need:
And that finished our Do It Yourself Cold Air Intake Project!
Totals and Results
Now for some total costs, time, and performance gains.
Stage I: $12.25
Stage II: $30 (Around this for a high perfomance air filter + the rubber stopper)
Stage III: $62 (For the parts list I originally listed) Total: $104.25
Not bad considering we saved over $200 with our product that beats what performance companies are selling on the market.
Total Time: 2 hours
Roughly 45 minutes for stage I, 10-15 minutes on stage II, and an hour on stage III.
As for perfomance gains, I don't have a dyno at my disposal, so everything isn't backed up with a dyno sheet. Take my opinion as you will but this is what
I feel has been gained. About 20% increased throttle response at mid range (especially as cruising speeds of 60-75 or 2900-3400RPMs) and quite possibly an
increase of 3-5HP at the wheels (that is always debatable of course). As for torque, I'm still figuring how to calculate that without a dyno.
Now I'm sure the question of hydro lock is swimming through your mind (no pun intended). Think about it this way. Water would have to travel up 3 feet of initial
hosing (our grille hose to our airbox), make it past an airbox (which has DRAIN HOLES in it), through a filter, and through a tube (which in my case has an incline between the first 45
and the second 45). I don't believe water will be getting to my engine anytime soon. Granted I still can't go through flooding, but I never intended to change that problem.
Also there is a noticable difference in sound between acceleration and cruising. But the coolest sound is the whistling while cruising at 75MPH or so. You can literally hear the air rushing
down the intake tube into the throttle body. Sometimes I turn off the radio and just listen to that while driving!
But enough of my so-called car intelligence, why don't you just watch this video I made of the final outcome instead:
If you have any questions or comments you can e-mail me at Jta91[at]optonline[dot]net (at=@ and dot=.).