• Review/DIY of new STETT Version 2 Cold Air Intake for the 335/135 N54 by Former_Boosted_IS

      As many of you know, I have a STETT Performance Cold Air Intake (CAI) on my car. About a month ago, STETT mentioned they have a version 2 of the cold air intake that made installation easier, increased intake piping diameter, and slightly increased filter size. I know a few members were curious about the new product, so I thought I would take some time to review the product for the forums.

      This review will note my experience with STETT, detailed pictures of the v.2 kit, comparison of the v.2 kit versus the older kit, update to install process, and finally my conclusions.

      Experience with STETT Performance

      I make no secrets that STETT Performance is really one of my absolute favorite vendors. I have had just a ton of success with them on my car and this was no difference. STETT is always very knowledgable and customer friendly. Their shipping is second to none. STETT emails you a notification you of a pending shipment, notifies you when the package has been picked up, and email you within 10 minutes after the package has been delivered. I have yet to ever see better post purchase customer service. One thing to note, the kit did not come with installation instructions, but with this and my former DIY, I think that should cover installation nicely.

      The box came to my house with my new STETT oil cooler kit in a large cardboard box.

      All items are protected with styrofoam peanuts, bubble wrapped to protect the products during the shipment, then the pipes are plastic wrapped.

      Once I opened the box, I got to see the kit as a whole. 3 pipes, 2 couplers, clamps, and filter.

      STETT Performance is known for their distinctive black piping and these look really, really good!

      The finish on the pipes is nothing less the perfect looking. The black color is just sick!

      STETT's couplers are always high quality and black to match the rest of the kit.

      Finally, the filter is seperately packaged and plastic wrapped to protect it.

      Another incredibly positive experience with STETT, but I have come to expect nothing less from these guys.

      STETT Performance CAI V.2 kit versus Original CAI

      I wanted to focus a little on the differences between the original STETT CAI and the V.2 of the STETT CAI. There are obvious differences, but I did want to quantify the differences for that that are interested in this product. Keep in mind that flow is proportional to cross sectional area, so small increases in pipe diameter will equate to better flow.

      First lets look at the piping that is post y-pipe. Notice what was once one pipe is now broken down into two pipes connected by a silicone coupler.

      There is a small difference in the pipe diameter, but everything helps flow.

      One of the big and very noticeable differences is in the y-pipe area. The shape is different, the angles are different, and the runners are noticably larger.

      The runners again are the biggest difference in this kit.

      The diameter on the runner of the original STETT Performance CAI is about 2.5".

      The diameter on the runner of the V.2 STETT Performance CAI is very close to 3" now. That is a significant increase in size from the runners to the exit of the y-pipe.

      The filters are very nearly the same size with a small increase in diameter to meet the piping of the intake.

      So the changes are as follows:
      • Y-pipe has an increase of around 1/2" on the runners
      • A small increase on the exit of the pipe
      • The piping post y-pipe has a small increase in diameter
      • The exit of the filter also has a small increase in diameter


      Much of the DIY installation was covered in my original review and I would encourage you to refresh yourself in that review if you are doing the installation. I will still cover some of the differences on this install. It is important to note, you should always clean the inside of any intake to assure that there is no debris in the pipe! I alway go through the piping with steel wool the dislodge any debris and then clean it is running water.

      Once you remove your former intake, this is a very easy install on the v.2 STETT CAI. I always jack up my car and remove the fender liner so I can have full acess to my fender well for the install. It takes 15 minutes and just makes life easier.

      The first thing I installed was the intake y-pipe. To make my life easier and decrease the chance of scuffing the pipe, I installed the 90* bend silicone coupler on the y-pipe and angled it slightly toward the driver's side headlight. I also remove the clamps completely to protect the pipes from scratches. From here, I inserted the ends of the runner into the turbo intake piping.

      Next, I installed the upper intake piping. Notice I wrapped all my pipes in towels to protect the black coating during the install process.

      Next I installed the lower intake piping. Note the long section should be facing the engine while the short bend should be facing the fog light. Make sure you angled the short bend opening toward the location where the filter will sit. I placed my filter in its final location to make sure I got things lined up well.

      Once I was able to verify no interference with the piping and either the headlight or the body of the car, I started to assemble everything. First, I inserted the pipe into the air filter.

      From here, I made sure that all the pipes were inserted securely into the silicone couplers. Then I wrapped the clamps around the couplers and loosely tightened the couplers to allow for final adjustment.

      With everything lined up well, I torqued all the clamps down. The job is actually pretty easy to be honest, and I have to say much easier than the original CAI. The V.2 STETT CAI added a second coupler and broke the post y-pipe into two seperate pieces to make the installation easier / fitment better. I think they absolutely accomplished their goal. The job was 45 minutes most for me.


      The look of the STETT CAI is tremendous. The black pipes from STETT have such a glow to them and look so good in the engine bay! Have a look for yourself.

      Previous IAT Testing With STETT CAI versus DCI Intakes

      For those that are interested in the results from the STETT CAI versus DCI intakes, I have posted the testing I did about 18 months ago.

      Products Tested

      This test was an IAT analysis between the BMS DCI and STETT Performance Cold Air Intake.

      Testing Procedure in 2009

      Tests were conducted to determine how the STETT Performance CAI and the BMS DCI would perform in multiple situations. I collected nearly 70,000 data points in a specific testing procedure. Each test was conducted in the following way:

      1) JB3 8D4 Rev.4 on map 7 (same as map 6 on 1.2).
      2) This is critically important to note... the car has an Active Autowerke Intercooler.
      3) Car was warmed up for 18 minutes in identical driving routes, rpms, and speed.
      4) Data was logged using Bavarian Technic software and BMS Tuning Tool.
      5) Ambients were logged in an attempt to replicate similar conditions.

      Four tests were done on each intake using an identical car setup. The tests are:

      1) Approximately 10 minute highway runs at 70 mph
      2) Approximately 10 minute standing idle
      3) Approximately 10 minutes of stop and go driving
      4) 3 back to back wide open throttle (WOT) full gear pulls

      Ambient Conditions

      The BMS DCI was logged under the following conditions:

      Temperature of 67 degrees F
      Relative Humidity of 54%
      Pressure of 30.15" / 1020 mb

      The STETT Performance CAI was logged under the following conditions:

      Temperature of 70 degrees F
      Relative Humidity of 84%
      Pressure of 30.09" / 1018 mb

      Note the BMS DCI was tested at 3 degrees F colder temperatures and 30% lower relative humidities.


      Highway Runs

      I am going to start with the highway runs because these we would expect to be identical. These tests were done at 70 mph with about a 2 minute turn around in the middle of the runs. You can see where the AITs rise slightly while waiting at the stop light.

      Here is the IAT graph of the BMS DCI

      Here is the IAT graph of the STETT Performance CAI

      Both showed very consistent results. Around 82 degrees F through the entire highway runs. No difference at all between the BMS DCI and the STETT Performance CAI.

      Idle for 10 minutes

      This was a simple test. Let the car sit after the highway run for 10 minutes.

      Here is the BMS DCI IAT graph:

      Here is the STETT Performance CAI IAT graph:

      The BMS DCI graph shows the IATs warm up faster in the first 5 minutes or so, then they become very close by the end of the ten minutes. The BMS DCI was at 112 degrees F after 5 minutes while the STETT Performance CAI was at 106 degrees F. The BMS DCI was at 121 degrees F after 10 minutes while the STETT Performance CAI was 119 degrees F after 10 minutes. The STETT Performance CAI definitely performed slightly better here with colder AITs.

      Stop and go driving

      It is important to note here, there were a few more stops in the testing with the BMS DCI only because I got stuck at more lights.

      BMS DCI IAT graph versus RPM:

      BMS DCI IAT graph versus speed:

      STETT Performance CAI IAT graph versus RPM:

      STETT Performance CAI IAT graph versus speed:

      I have to say both performed nearly identical to one another. Both hovered from 85 degrees F to 95 degrees F during the entire runs. The single most noticeable thing was that during hard acceleration the STETT Performance did seem to drop AITs faster, but I would not give an advantage to either.

      3 wide open throttle long gear pulls

      Ok, this is the big daddy and the single most important test I did. There is one piece of bad news. I accidentally cleared the first run off one of my data logs from the Bavarian Technic software, but did log the run using the BMS Tuning tool. The bottom line is the graphs will show run 2 and run 3.

      From the BMS Tuning Tool Run 1 on the BMS DCI produced a peak of 109 degrees F and the STETT Performance CAI produced an IAT of 101 degrees F. I apologize for no graphs, but the next two graphs show more than enough.

      IAT graph of run 2 and 3 on the BMS DCI:

      IAT graph of run 2 and 3 on the STETT Performance CAI:

      IAT graph of run 2/3 of the BMS DCI versus the STETT Performance CAI:

      The data is very clear here. The BMS DCI had a peak IAT that was 8 degrees hotter on run 1, 10 degrees hotter on run 2, and 8 degrees hotter on run three. This is an average of 8.7 degrees hotter for the BMS DCI over the STETT Performance CAI over the three runs.

      The analysis of the graphs clearly shows the entire temperature climb is shifted down by the STETT Performance CAI. There is no exponential difference, but a step difference between the two. You can also see the difference is held through the 1 minute or so it took me to turn around for another run. The data is pretty definitive.


      In May of 2009, I showed that the STETT CAI did indeed produce colder IAT temperatures over a traditional DCI intake at WOT without any increase in wastegate duty cycles that were notable. My averaged was 9F colder IATs with the STETT Perfomance CAI versus the traditional DCI intakes. Note, this difference was with an aftermarket intercooler, so the difference would be quite a bit bigger with the stock intercooler. I think this put to rest that a CAI will indeed produce colder air to your engine which ultimately is the goal here.

      The STETT Performance V.2 Cold Air Intake has made the installation really a lot easier and I didn't consider it a very difficult install before. The added couplers give more room to adjust the piping and that is definitely a help. The V.2 kit also increases the diameter slightly on the opening for the filter, the post y-pipes, and significantly increases the diameter of the runners on the y-pipe. This is a quality kit with STETT's distinctive black coated pipes that look really good in your engine bay.

      Shipping from STETT was top shelf as always... pre-shipment notice, pick-up notice, and delivery emails. STETT is the gold standard here.

      STETT made an already great product even better. The additional couplers add a lot of flexibility to the kit and the installation is a breeze. I cannot imagine any DIY'er should have a problem whatsoever.

      I don't think anyone will be suprised, but I wouldn't hesitate for a fraction of a second to purchase from STETT again.

      This article was originally published in forum thread: Review/DIY of new STETT Version 2 Cold Air Intake for the 335/135 N54 by Former_Boosted_IS started by Sticky View original post
      Comments 3 Comments
      1. 1cleanAMG's Avatar
        1cleanAMG -
        I like my Injen Intake better
      1. dzenno@PTF's Avatar
        dzenno@PTF -
        What did you do with your stett v1 intake?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by dzenno Click here to enlarge
        What did you do with your stett v1 intake?
        This was written by Former_Boosted_IS, not me, I don't know what he did with it.