Can an air filter really make a difference?
When it comes to enhancing a car’s performance, an air filter might not seem like the most exciting upgrade, but it can make a noticeable difference. I’ve replaced air filter panels and even complete air intake systems before, such as the Eventuri on my Mini Clubman JCW. In my experience, swapping the OEM panel filter for a performance one often delivers tangible improvements, though results can vary from car to car.
When I purchased the BMW i8, I knew it wasn’t a traditional sports car. It has the looks, some performance, and a… let’s say “unique” engine note. So, I wondered, would upgrading the air filter make a difference? After some research, I discovered that complete air intake systems are unavailable due to the i8’s awkward mid-engine layout, but panel filters are a viable option. I decided to give it a shot with a Pipercross performance air filter.
What Does a Pipercross Air Filter Promise?
Here’s why I chose the Pipercross filter:
- Enhanced Airflow: 30–40% increase in airflow compared to stock filters.
- Improved Fuel Economy: Optimised airflow for better engine efficiency.
- Lifetime Warranty: Peace of mind with a limited lifetime guarantee.
- Environmentally Friendly: Washable and reusable, reducing waste.
For just £60, it seemed like an easy and cost-effective upgrade. Based on my past experiences, Pipercross filters have always delivered, improving airflow and even adding light pops and crackles on other cars.
Step-by-Step Guide to Replacing the BMW i8 Air Filter
Replacing the air filter on the i8 is more involved than on front-engine cars, but it’s still manageable with patience.
1. Accessing the Engine
The BMW i8’s engine is located behind the rear passenger seats, accessed through the boot. Getting to it requires some preparation:
- Climb into the boot: Due to the car’s mid-engine design, you’ll need a step ladder to safely get in.
- Position yourself: Be prepared to either hunch over or carefully sit on the boot’s ledge.
2. Removing Panels
To reveal the engine, a series of panels must be removed:
- Boot Cover: Lift it out to access the engine bay.
- Foam Board: Remove this lightweight piece for the next layer.
- Metal Panel: Undo seven hand-turn screws to remove the final barrier to the engine.
At this point, the engine is visible, though it’s a very tight space to work in.
3. Accessing the Air Box
The air box is a bit tricky to navigate due to the tight engine bay. Follow these steps:
- Undo two clips securing the air box cover.
- Loosen the metal duct ring with a flathead screwdriver.
- Remove the Mass Air Flow (MAF) Sensor: This step is optional but highly recommended to make the process easier.
Once the air box cover is loosened, wiggle it off using a sideways motion.
4. Replacing the Filter
- Swap the OEM stock filter with the new Pipercross performance filter.
- Note the size and quality difference between the two filters. The Pipercross filter feels more robust and designed for optimal airflow.
5. Reassembling
Reinstall everything in reverse order:
- Attach the air box cover and secure it with the clips.
- Tighten the duct ring and reconnect the MAF sensor.
- Replace the metal panel, foam board, and boot cover.
Results After Installation
What’s changed?
- Noise: There’s no increase in noise, but under acceleration, the sound is noticeably crisper. The electric motor produces a faint whine, almost like a supercharger.
- Performance: While gains are marginal, acceleration feels smoother and more linear at the upper end, suggesting the engine is breathing better.
- No Pops or Bangs: Unlike my Mini, the i8 didn’t develop any additional exhaust sounds.
If you’re looking for a noticeable sound change or a dramatic performance boost, this upgrade alone might not deliver. A new exhaust might still be necessary for more character.
Final Thoughts
Upgrading the air filter on the BMW i8 is a worthwhile enhancement, especially considering its affordability and ease of maintenance. While the improvements are subtle, they contribute to a more refined driving experience. Plus, the Pipercross filter’s lifetime warranty and environmental benefits make it a smart choice for any car enthusiast.
Would I recommend it? Absolutely, but keep your expectations realistic. For a more exciting transformation, pairing it with other modifications, like an exhaust upgrade, might be the next step!
