In my last post, I covered adding more power by installing the 034Motorsport Stage 1 ECU and TCU tuning. In this post, I'm going to cover how you can easily extract even more power and better throttle response by upgrading the factory air intake system. Intake upgrades like this are a favorite for me because they're relatively easy to do while providing very satisfying results.
With a relatively popular platform like the B9/B9.5, there are also lots of options to choose from. Due to the relatively small area of space that the airbox can take up, there's no way to truly increase the available volume of air to improve airflow. While installing a higher flowing filter will help improve the speed and possible velocity of the intake air, it's still held back by the volume of the air box.
However, in my testing and research, I found that with any of the available intakes for the B9 2.0T, the total volume or capacity of the intake doesn't increase. This makes sense, as there is only so much available area in the engine bay of the car where the airbox can fit. Because of this restriction to the overall airbox volume, open intakes make more sense. If the airbox isn't opened, it will restrict the amount of available air that can enter the turbocharger.
One particular intake that I'm a huge fan of (and almost purchased for this project) is the 034Motorsport P34 Cold Air Intake. This intake is completely open on the back-side to increase the engine's air flow, which I'm a big fan of. And while the P34 intake looks great in the engine bay with it's OEM+ plastic look, 034Motorsport also makes a carbon fiber X34 version if you're interested in adding a splash of style as well.
Balancing Practicality and Performance
While I do enjoy several of the available intakes for this platform, I am also trying to keep my build somewhat practical and low cost to keep my wife happy. After all, the name of this series is Project Practical Performance. To keep in line with the practical element meant going down the DIY route.
I'm also going to mention that I fully understand that not everyone is the DIY type. You also might not be completely comfortable cutting apart the factory airbox, or have access to the right tools to do so. If either of those situations apply to you, please by all means, purchase a ready to install intake such as one of the 034Motorsport intakes I've listed above. Remember, I'm mostly doing this to save some money to appease my wife. I also already have the skills and tools to do this safely. I'm also not responsible if you find a way to injure yourself in the process.
Opening up the intake really does give a huge boost to the available intake air provided to the turbocharger. By simply cutting a few holes in the airbox, you're essentially removing a huge restriction and allowing air to flow more freely into the turbocharger. With the enclosed factory airbox, the turbocharger has to work harder to pull all of it's airflow from the small intake hole on the front grill.
If you look at the factory airbox used on the B9 RS5 models, they also have an opening on the side of the intake to help alieviate the airflow restriction as well. The photo above shows this opening.
Fortunately, with the help of a Dremel tool, cutting wheel, and some sand paper, you can easily make some nice openings into your factory airbox. Just take your time, cut at a lower speed and you'll be done in no time. I also used some sand paper to smooth over the edges of the cuts. Remember, there's no right or wrong shape to cut out, but feel free to copy my style if you'd like.
Smoothing Out the Air Flow With 034Motorsport
The factory airbox supplies air directly to the turbocharger via a corrugated plastic hose. It's not hard to deduce that the corrugation isn't the best for promoting smooth air flow.
034Motorsport makes a great part that covers this area of improvement. Their High-Flow Silicone Turbo Inlet Hose is a direct replacement for the factory corrugated plastic hose. It's constructed from wire reinforced silicone to prevent deformation when the turbocharger is fully spooled. The silicone also provides a smooth surface that promotes faster airflow.
This intake will need to be able to more quickly move that extra air due to the next part of my intake upgrade.
The Highest Quality Air Filter Possible
Now, I could have easily gone with the tried and true K&N air filter, but I decided to take things a step further. You see, there is a company that we deal with quite regularly that makes the intake systems for our TCR race cars: BMC.
BMC is a lesser known Italian company that specializes in making the highest flow intakes and intake filters available for several vehicles. This includes actual race cars such as those driven in IMSA or other prominent world endurance challenge races, such as the 24 Hours of Le Mans.
Fortunately for this project, BMC makes a drop-in factory replacement intake air filter for the Audi B9 A4 Allroad 2.0T (it also fits all other B9 A4, A5, S4, S5 and RS5 vehicles). Installation is as simple as removing the factory intake airbox cover, twisting off the old filter and twisting on the new filter until it locks into place.
This new filter also comes with some bragging rights. That's because there is no better filter available for the Audi B9 chassis. That's right, this budget intake has a filter that not only flows more air, but also provides better filtration than any other intake on the market.
Conclusion: Better Airflow (and Sound) for Less
After installing these parts, I immediately noticed that acceleration was smoother and throttle response was sharper as well. I also appreciated the improvement to the middle and upper sections of the powerband when under full throttle. Power now comes on a bit smoother and stronger no matter what RPM I'm at when I hit the throttle.
The sound has also pleasantly improved as well. The turbocharger spool is much more pronounced than before, and the sound of air rushing into and out of the turbocharger is also much louder. The increased airflow combined with the more open nature of the airbox has also given the intake more of a growl that you really notice when pushing deeper into the throttle pedal.
Combined with the gains from the 034Motorsport Stage 1 ECU Tune, these intake system upgrades provide some much needed improvements. Before upgrading the intake system, I could feel the engine being held back. Now, I can floor the throttle and feel the engine taking advantage of the increased air flow.
Overall, I'm very happy with this upgrade and highly recommend others to upgrade their intake system as well. We have tons of options for this in stock, all you need to do is select your vehicle model and go to the air intake system category to see what we have available for your vehicle.
Because some people might also be interested in doing this same upgrade to their own B9 Audi A4, A5 or Allroad 2.0T, I put together all of these parts into one handy Budget Intake Upgrade Kit. This kit includes all of the same parts I installed to my own car in this article.
You may have noticed that there is no photo showing the BMC filter installed to the airbox. This is due to how the filter is snapped into the top portion of the intake. Because of this, there's unfortunately no way to take a picture of it in the airbox when the top has been removed. Just imagine a big red filter connected to that wonderful 034Motorsport turbo inlet hose in the photo above.
Next Up: Ignition Service and Upgrades
In the next update, I'll cover servicing and upgrading the ignition system for better overall performance and reliability.