2.0T FSI Air Filter – Mann Filter OE Equivalent

Mann Filter - Part Number C41 110

I’ve done a few maintenance items the last few days. The fuel filter was one and now the air filter. Mann Filters has an OEM equivalent filter for the 2.0T FSI motor with the part number C41 110. I purchased it from Amazon. Mann most likely makes the original filter but the aftermarket Mann filter has a very slightly different look from the OEM filter. The foam is slightly lighter in color and softer but thicker in overall dimension. The filter material looks the same. It fits perfectly fine in the airbox. Anyway, it was around 15 dollars from Amazon, about 5 dollars cheaper than my local dealership.

Mann Air Filter - C41 110 - Edge Detail

Mann Filter - C41 110

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Carbonio Air Scoop – Some Thoughts

Carbonio Intake Scoop

I recently purchased a used Carbonio air scoop for a great price.  The cosmetic condition is not mint but completely workable.  If you’re not familiar with the Carbonio intake for the FSI, it’s basically a carbon fiber replacement for the stock air scoop with a drop in air filter.  I am not running the drop in filter.  It has been the subject of many debates because it only replaces a portion of the stock intake and costs more than many full replacement intakes.

Stock fresh air intake through grill

The claims are that the stock intake and filter combination is a big restriction and that a filter on a stick style intake can flow much more air.  I’m not convinced that the stock intake is a huge restriction, much less the stock filter.  Maybe the ribbed tubing after the airbox, but I don’t see the stock airbox being too bad at airflow.  My only knock against the stock airbox is that they made filter replacement more difficult than necessary.  The stock airbox has a nice feed of cool air from the front grill.  However, the scoop that it uses to feed the intake is designed with a split, diverting some of the air downward to deflect debris and water.  This may also allow the intake to get air from the engine bay though.  The Carbonio scoop gets rid of that split scoop and funnels all the air into the airbox.  While more debris and water may make its way into the interior of the airbox, the filter is there to stop it, just as a filter on a stick intake would.

The improvement I see with the Carbonio scoop is that the design should allow for positive intake pressure when the car is moving, basically a ram air setup.  That slight positive pressure will help overcome any restrictions in the stock intake.  The Carbonio scoop also draws all air from outside the engine bay, unlike the stock scoop.  I don’t know how much of a difference this truly makes, just thinking out loud.

You’ll notice that the intake looks yellowish.  This is because this is an older, used intake and the resins used in the carbon fiber have yellowed.  I don’t know if the newer Carbonio intakes do this but older ones were quite notorious for yellowing in the heat.

Cabin Air Filter

Cabin Air Filter CUK-2939

With spring and summer right around the corner, it might be a good time to check on your cabin air filter.  It is located right underneath the glovebox and is completely worth doing yourself.  No need to pay the dealership a ridiculous amount of money.

Depending on your area and how often you use your A/C, these filters can get dirty real fast.  It’s usually time to check when you notice a bad smell starting to come from the vents.

Here’s an excellent DIY with pictures from the VWVortex.

Amazon has excellent pricing for a Mann cabin air filter.  The part number is CUK 2939.

Stock Engine Cover/Intake

Well I’m a fickle person.  Over the course of the past week and a half, I’ve been tinkering with my intake and diverter valve setups.  I think I’ve finally settled on one; stock.  I know it is quite an about face, but I’ve come to the realization that the stock setup is actually quite good and does not detract from power.  It has excellent filtration, a good source of cold air, and is excellent at avoiding water intake.

 

The stock engine cover, not exactly your worst enemy

MAF Design

The stock engine cover uses an oval maf sensor housing, one that isn’t easily duplicated in aftermarket housings.  In fact, I don’t think there are any aftermarket intakes that accurately mimic the stock housing.  Round intakes can come close but not 100%.  The necessity of 100% accuracy is debatable but the closer you are, the better.  Fujita ignored this and was rewarded with the worst performing intake for the MKV.  Wholly inaccurate maf measurements and worse performance.  Even certain versions of the BSH diverter valve kit threw the maf sensor readings off, not to the degree of the Fujita, but enough to reduce performance.  The stock housing also contains a flow straightening screen which helps the maf read air flow as accurately as possible.  In short, you do not want inaccurate maf readings.

 

Oval tube and flow straightener

Inaccurate maf readings can lead to a multitude of problems such as reduced performance, poor gas mileage and poor throttle response.  Most of these result from messing with the short term (STFT) and long term (LTFT) fuel trims.  Here is a good article from Ross-Tech explaining how fuel trims work: Fuel trim info.  Basically you want to keep your trims around as close to zero as possible.  STFT has a +-5% range while LTFT is +-10% I believe.  I’m not so sure on the LTFT.  If you exceed these ranges, your performance will begin to suffer.

With the stock intake, my STFT is less than +- 1% and the LTFT is less than +-2.5%.  The aftermarket intake showed trims of -2.5% and around 5% respectively.

 

Maf position in stock intake

Stock vs. Aftermarket

The stock intake feels much better down low.  Chalk it up to the MAF area design or location but I cannot deny that it feels much more responsive down low.  The metal of the aftermarket intake pipe may be absorbing heat when the car isn’t moving.  In the upper rpm range, the aftermarket intake feels like it pulls harder/better.  It’s possible that an advantage in air speed may show up once the engine starts requesting more air.  Another possibility is that the airflow in the tube becomes less turbulent as speed increases, allowing the MAF to read the mass correctly.

Filtration is one area where the OEM intake will always win.  As good as the AEM filter may be, it is not going to beat the OEM cellulose filter.  The stock filter also has a huge amount of surface area, with more material and pleats than the aftermarket filters.

The noise difference is not drastic between the BSH and stock intake.  The BSH is already one of the quietest intakes and stock is well, stock.  BSH’s intake does have a deeper growl.

Why would you want stock?

I’m not going to say that aftermarket intakes have no place.  I’m just reorganizing the priorities for my car.  If the stock intake can provide me with 98% of the performance of an aftermarket intake, why not?  I ran an aftermarket intake for around 40,000 miles.  It has certainly served me well.  I just like to tinker with things.  Nothing purely scientific, I know, so take my experiences for what it is. But you can be sure that the MAF area has certainly caught my eye and a lot of engineering did go into the design of the cover.  I’m just deciding that they did a pretty good job.