The Ultimate BMW N54 Charge Pipe & BOV Guide (DIY)
As you begin to modify your BMW 135i, 335i or 535i, a metal charge pipe should be one of your first upgrades. The stock plastic charge pipe is prone to cracking or exploding when tuned. In this article, I’ll discuss charge pipe and blow off valve options so you can decide what is best for your N54. The second half of the article will cover the installation process in detail.
Charge Pipe Considerations
When shopping for a charge pipe, there are four main things to consider:
- Quality
- Fitment
- Price
- Diverter/Blow-off Valve options
This upgrade simply boils down to a metal pipe and a valve. It does not increase horsepower, but instead improves reliability. It’s not worth spending a ridiculous amount of money on a metal pipe, but it is important to get high-quality parts.
Do not purchase knock-off charge pipes with fake blow-off valves from eBay or Amazon. I recently read a post about a knock-off BOV coming apart and getting sucked into the intake ports. Most of the no-name charge pipes don’t fit and are finished poorly with sharp edges and metal burrs inside. Not only that, but they come with cheap hardware as well. Stay away.
Make sure the kit you choose includes T-bolt clamps instead of worm gear clamps. The charge pipe is pressurized and worm clamps are known to fail under pressure at the connection to the intercooler. The proper solution is a T-bolt clamp, which BMS includes with their charge pipe. Others do not.
Most charge pipe kits re-use the stock o-ring and c-clip connection to the throttle body, but some use a coupler and clamp. I recommend a charge pipe that retains the stock o-ring and c-clip connection and to avoid any that require an aftermarket coupler. The throttle body does not have bead to keep a coupler in place, so the locking clip is the best option.
The Best N54 Charge Pipe
In my opinion, the BMS charge pipe with TiAL blow-off valve is the best bang-for-your buck option available. It fits well, has a durable wrinkle black finish, has two NPT ports, keeps the stock C-clip connection, includes T-bolt clamps and each pipe is inspected and de-burred. It is also offered in two variations, one for diverter valves and one for blow-off valves.
Blow-off Valve or Diverter Valves?
Next, you must decide if you want to retain diverter valves or replace them with a blow-off valve. This is important because the charge pipe itself is configured differently depending on which option you choose. For diverter valves, the charge pipe will have two extruding ports on it. For blow-off valves, the charge pipe will have a single flange on it.
Blow-off Valve
I recommend upgrading to a charge pipe with a blow-off valve because blow-off valves are reliable and serviceable. Burger Motorsports offers an affordable charge pipe package with a genuine TiAL BOV, which I chose for my BMW 335i.
Some charge pipes allow you to choose the blow-off valve; TiAL, HKS, Turbosmart, etc. This decision largely comes down to brand and sound preference. The TiAL blow-off valve is the most common and I prefer it because it has been reliable on my other BMW and does not have an obnoxious venting noise.
If you opt for the TiAL blow-off valve like I did, it’s important to upgrade to 1/4″ vacuum line. You can use the BMS adapter fitting to accomplish this. Installation is very simple.
Diverter Valves
If you choose to stick with diverter valves, the cheapest option would be to purchase only the metal charge pipe and transfer over your OEM diverter valves. You will save money, but you are also at risk of your higher mileage diverter valves failing or sticking open/closed.
If you prefer to use diverter valves, I recommend purchasing a DV-style charge pipe and adding these Turbosmart Kompact N54 diverter valves. Then you are protected with a solid charge pipe and robust diverter valves.
Installation (How-To)
Installing an upgraded charge pipe is one of the easier modifications you can do. It’s not as simple as swapping out an air filter or changing your oil, but it can be done by a novice mechanic.
Watch the video at the top of the page for a step-by-step guide to install a charge pipe on your BMW 135i, 335i, or 535i. You will need a set of torx bits, a socket set, and an electric screwdriver will speed things up.
When it comes time to install the new pipe, slide the pipe on to the throttle body and then install the c-clip when the pipe is firmly attached. You should hear the c-clip click into place. Tug on the pipe to make sure it is properly seated.
