May 1, 2011

Cold Air Induction for S10

Custom Cold Air Intake

Custom Cold Air Intake

Over the past few weeks I have been working on putting together a cold air induction for my 2003 2.2l S10. Not so much to “increase horsepower” as so many manufacturers brag about, but more so to streamline the engine bay. Since I intend to replace the 2200 engine’s mechanical fan with an electric fan to decrease drag on the engine I need to clear some space. Plus long term maintenance on the engine will be simplified with a cold air setup as opposed to the stock air box and tubing.

Construction Overview

I put this cold air system together with 3″ (Inner Diameter) PVC pipe, two 90 degree elbows, a 45 degree elbow, a rubber coupler, some plate metal, a hose adapter, 5/8″ heater hose, and a K&N air-filter. I spent roughly $60 putting this together including the K&N air filter. A couple of things I would like to say off the bat:

  1. 3″ piping is overkill for this little 2.2l engine. The throttle body is only about 2.5″-2.75″ inches in diameter.
  2. Because of the small throttle body, the rubber coupler has to be negotiated with to get it to go from the 3.5″ outer diameter of the PVC to the 3″ outer diameter of the throttle body.
  3. 3″ PVC does not fit in the small amount of space available if you have AC. It takes God’s grace and patience to make this work. Expect this to be a painful experience.
  4. This project is about the enjoyment of designing and executing, and getting to solve problems. If you just want a cold air unit at a “good price”, DO NOT WASTE YOUR TIME. While this cost me about $60 to make, it took many many hours beyond what I expected due to the fact that 3″ PVC does not fit and there is no 2.5″ or 2.75″ PVC available (at least at my local hardware store).


  • Roughly 3′ of 3″ PVC. This includes material for waste as you will likely cut at least a piece wrong.
  • 1-90 degree elbow that the PVC fits into on both ends (Belled).
  • 1-90 degree elbow that the PVC fits into one end (Belled), and the other ends is the same diameter as the PVC (3.5″ O.D.) (sleeve).
  • 1-45 degree elbow hat the PVC fits into on both ends (Belled).
  • 1-5/8″ fitting to connect the crankcase ventilation tube to.
  • Roughly 1′ of 5/8″ heater hose to extend the crankcase ventilation tube.
  • Conical air filter with a 3.5″ opening. I chose the K&N RU-3130 which I picked up for $26 shipped online.
  • Miscellaneous plate metal, nuts, bolts, and washers to create brackets with.


CAI Throttle Body Connector crunched

CAI Throttle Body Connector crunched

The construction of this intake is pretty straightforward once you have the right parts. I recommend starting the construction at the throttle body. This is of course after you have removed the stock air box and related piping. The rubber connector from the throttle body to the first 90-degree bend (the one that is sleeve style) is the most challenging part of the build. This is because it really does not fit. First you need to cut the coupler down to about 1.5″ in length total. From the hardware store this is about 5″ long. Once you are down to the roughly 1.5″ you quickly realize why the .5″ transition is going to be so difficult, that being because there is little-to-no distance to do it over.  This can be overcome with some persistence. I was able to get this to fit through a process of clamping it down for extended periods (as I worked on the rest of the intake) and by removing it for periods and heating it with a MAP gas torch. Once I had heated the rubber connector I would quickly re-attach it to the throttle body and the 90-degree bend. After doing this about three times over the course of 4 hours (remember I said DO NOT do this job for cost savings) the coupler started to fit fairly consistently. This was a process of majorly deforming this coupler over time through the use of heat. When you try to fit your 90-degree bend in there with the un-modified couple you will learn that the reason I went through all of this was because there is not enough space to fit the coupler and the 90-degree bend. You also have to trim down the 90-degree bend’s sleeve side. I cut this down to about .5″ after the bend, although your mileage may vary.

Once you have securely fastened the 90-degree elbow to throttle body it is fairly smooth sailing from there. The connector for the AC compressor can seem challenging to maneuver around, but you will need the intake point in an upward manner anyways to clear the wire loom for the spark plug wires below.

CAI Clearing AC Lines

CAI Clearing AC Lines

CAI Trimmed Fan Shroud

CAI Trimmed Fan Shroud

At the next 90-degree turn at the AC compressor you will start aiming the intake down towards the former location of the air box. The fan shroud will need some trimming to accommodate the 3″ PVC. You will also need to experiment with the downward angle to find what drops the intake enough to allow the two AC lines to pass over the top and to allow the hood to close properly without point the intake to far down that it interferes with the fan or allowing space to attach a reasonably sides filter.

CAI AC Mount

CAI AC Mount

I found that after attached the 90-degree bend at the AC compressor it was a good time to build a bracket to support the intake. I used some 3/16″x1″ flat steel I had and some nuts, bolts, and washers. Once I had that fabricated up I used a rubber dampener from the original intake system between the bracket and the AC compressor to reduce the vibration related noise.

From there it was the final straight away and 45-degree turn down to the air filter. This section’s dimensions’ and angles will depend on your filter. If you use the K&N filter I chose you can very conveniently position the intake downward while still allowing a solid 1″ of clearance between the bottom of the filter and the body of the S10. It is a good idea to ensure that the filter is not resting on any part of the body as you do not want to transfer vibration noise from the intake to the body. Prior to final fitting of these parts I recommend building the second bracket which I attached to the former mount for the air box. Again I used 3/16″x1″ flat steel I had and some nuts, bolts, washers, and another rubber dampener from the original intake.

CAI air box mount and air temp sensor

CAI air box mount and air temp sensor

Next drill a hole for the intake air sensor (that is the sensor that is just a few inches up from the air box in the original configuration). I placed the sensor right below the 45-degree bend on the straight piece of piece of pipe that connected to the air filter. Once drilled out I simply used a dab of hot melt glue to hold it in place.

Lastly install an inlet into the intake, likely at the first 90-degree bend from the throttle body, to connect the crankcase air vent. This is a 5/8″ rubber hose that comes off the valve cover. I honestly have not done this yet although I have the supplies. I just need to track down a drill bit big enough.

Final Thoughts and Key Learnings

After having this installed for a week I would definitely say the increased throttle response is there, I do not believe there was much of any increase in gas mileage. I will not honestly know on the gas mileage for a few more day. That being said the 2200 series 2.2l engine definitely has a low tone and more aggressive note to it. Around 3k rpms there is a bit of a vibration that can be a little bit annoying at certain speeds/gears, but get below or above 3k by as little as 200 rpms and it passes.

  • Custom build is always a challenge. May times the cost is on par or more if you factor your time in (Do we really care though? We love to do this.).
  • 2200 series does achieve a deeper tone.
  • Engine seems to be more responsive.
  • Gas mileage is not necessarily impacted (will update once final results are in).
CAI Completed

CAI Completed


2 responses to “Cold Air Induction for S10”

  1. roland says:

    use a 1/8 drill to pilot drill your location for the 5/8″ hole the use a hole saw or spade bit, also a rotary file can be used to bring it up to size. spade bits work fine and you can get a hole set for like 5 bucks.

  2. Nathan Hein says:

    Great tip Roland.

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