BMW's N20 engine comes from the factory with respectable power and performance. However, enthusiasts often look to simple bolt-on mods for impressive power gains. An upgraded downpipe is one of the best bolt-on mods for the N20. Removing the restrictive catalytic converter from the downpipe helps unleash the N20's true potential. In this guide, we will compare N20 catless and high-flow catted downpipes, discuss the pros and cons of each, and list some of the top options on the market.
BMW N20 Upgraded Downpipe Performance
A downpipe is one of our favorite mods for turbo engines. The catalytic converter in the OEM N20 downpipe is intended to reduce emissions. However, it comes at the cost of reduced power and performance. The drop in pressure from pre-turbo to post-turbo greatly affects a turbochargers ability to spool. Hot exhaust gases accelerate as they look to expand into less dense air. Therefore, reducing back-pressure allows the air to escape faster leading to improved turbo spool and higher boost. As such, the best exhaust on an N20 would actually be no exhaust after the turbo - not exactly the most realistic proposal. However, worry not. Catless and high-flow catted downpipes are great options.
N20 Catless Downpipe vs High-Flow Catted Downpipe
Catless downpipe options for the N20 are the least restrictive, and will result in the best power gains and spool. However, catless downpipes do have a significant pitfall for some. Inspections and emissions testing are potential issues. If your state has emissions testing it is unlikely an N20 equipped with a catless downpipe will pass. If you're concerned about emissions then you may consider opting for a high-flow catted downpipe.
For those not worried about emissions, we highly recommend choosing a catless downpipe. They are generally cheaper than catted options and provide the biggest performance gains. However, a high-flow catted downpipe remains a solid choice for the balance of performance and cleaner emissions.
N20 Upgraded Downpipe Pros
- 15-20whp with catless DP (5-10whp with high-flow catted DP)
- Similar torque gains
- Quicker turbo spool
- Better top-end performance
- Intoxicating sounds
The biggest selling points are likely the power and torque gains. As indicated, high-flow catted downpipes will provide the same benefits above - simply to a lesser extent. A tune-only N20 may expect power gains of 15-20whp with a catless downpipe. Meanwhile, a catted DP will likely only add 5-10whp. Both will improve turbo spool but, again, the catless downpipe will show the best results. Speaking of spool, an upgraded downpipe will give the impression that the car is making more power than it really is. Quick spool will kick you back into the seat more aggressively and the butt-dyno will definitely approve of this mod.
N20 Catless Downpipe Sound
Another huge benefit to an upgraded downpipe is the sound. Catless downpipes do add a bit of noise on cold starts. However, once warm they're hardly detectable at idle. Dig into the N20's throttle and a catless DP provides a deeper, aggressive note. It's an intoxicating sound when you're looking to have fun. However, the exhaust remains quiet and does not intrude during modest cruising or highway driving. Overall, expect stock-like sounds when you want them and a more aggressive note when you're ready to open up the N20.
*Sticking with the trend, a high-flow catted DP will also make a bit more noise than stock but to a lesser extent than the catless DP.
BMW N20 Upgraded Downpipe Options
In this section, we'll discuss a few of the popular, high-quality N20 downpipe options on the market. This is not an exhaustive list as there are tons of different choices. There are, of course, options on ebay/Aliexpress that we recommend avoiding. Some have good experiences and others have nightmares. If you go this route, be cautious of the quality and fitment.
1) VRSF N20 Catless Downpipe
VRSF is our favorite option for bolt-ons on any BMW turbo engines. We believe their balance of price, quality, and performance is unmatched. It's hard to go wrong with an N20 catless downpipe from VRSF. Tested, proven, and great quality all at an excellent price. As with the other N20 catless downpipe options, expect power gains in the ballpark of 15-20whp.
VRSF N20 Downpipe Price: $249.99
Buy Here: N20 Catless Downpipe VRSF
2) Evolution Racewerks Competition Series N20 4" Downpipe
Evolution Racewerks (ER) offers both a catless and high-flow catted downpipe for the N20 engine. ER makes excellent products, but they do come in at a slightly different price point than the previously mentioned VRSF. The ER options start at $445 for a catless DP while the catted DP starts at $805.50. This is a great option for anyone looking to go the catted route. However, for a catless downpipe we recommend saving the money and opting for VRSF.
ER N20 Downpipe Price: $445-909
Buy Here: N20 Evolution Racewerks Downpipe
3) Turner Motorsport High-Flow N20 Catted Downpipe
We're not as familiar with this line of products, but the Turner Motorsports catted downpipe deserves an honorable mention. Their N20 catted downpipe looks to be a great product priced at $449. While it may sound expensive compared to VRSF, it's a great price point for a catted N20 downpipe.
Turner N20 Downpipe Price: $449
Buy Here: Turner Motorsports N20 Catted DP
BMW N20 Upgraded DP Summary
In our opinion, catless downpipes are among the best bolt-on performance mods for the N20. Expected N20 power and torque gains come in around 15-20 to the wheels. Quicker spool leads to an excellent kick that is sure to impress the butt-dyno. Top-end performance sees big benefits as the turbo will hold more boost up top. Additionally, catless downpipes make an intoxicating sound on cold starts and heavy acceleration, but remain quiet and composed for normal daily driving.
However, catless downpipes come at the cost of potential inspection and emissions testing issues. If this is a concern, a high-flow catted downpipe is a great option. Though catted DPs are generally much more expensive for lesser performance benefits. We ultimately recommend the VRSF catless downpipe as it provides a great balance of price, quality, and performance. Look to ER or Turner for great catted options. All things considered, it's tough to go wrong with any upgraded N20 downpipe.