BMW N63 Water-Methanol Injection Guide

Water-methanol injection (WMI) is a very capable form of fueling and cooling on turbo engines. Methanol is a high-octane fuel while water quickly cools temperatures due to its high specific heat capacity. Those are the two main benefits of N63 WMI, but it also comes with some risks. In this guide, I discuss BMW N63 water-methanol injection kits along with their benefits, risks, and performance gains.

N63 WMI Benefits

• 20-100+whp gains
• Cooler IAT
• Cooler cylinder temperatures
• Knock suppression
• Source of high-octane fueling

The massive power gains from N63 water-methanol injection really come from the lower bullet points. Water cools intake temperatures because of its high specific heat capacity. Essentially, water can absorb a lot of heat without significantly increasing its own temperature. On the other hand, methanol has an octane rating of 114. It also burns cooler than gasoline further aiding in cooling internal temperatures.

High-octane fuel and cooling benefits allow the engine to safely handle more ignition advance and higher boost. Ultimately, that’s where the potential 20-100+whp gains come from. However, it’s hard to state specific power gains since it depends on tuning, how heavily you rely on WMI, and many other factors.

With a small methanol mix (mostly water) on stock turbos and conservative tuning you may only see power gains around 15-20whp. N63 WMI can offer 75-100+whp with higher methanol flow on upgraded turbos. Again, it really depends on a lot of factors but the point is: water methanol injection can offer significant power gains.

E85 vs Water-Methanol Injection

Ethanol fuel – also known as E85 – is a high-octane fuel that can be found at some pumps around the United States. In my opinion, E85 is the superior fueling solution over WMI. Rather than needing separate tanks, pumps, lines, etc. you can simply fill E85 into the gas tank. Like methanol, ethanol has a high-octane rating and burns cooler than gasoline.

However, ethanol is demanding on the fuel system and requires ~30-40% additional flow to run full E85. It can also be challenging to find in certain parts of the US and world. That’s really where water-methanol injection comes into play. Since it’s separate, WMI actually reduces demand on the stock fuel system. It’s also easy to find online or at local racing & automotive shops.

Ultimately, there is a lot to cover when it comes to E85 vs WMI, and this is only meant to be a brief comparison. E85 is generally the safer, more consistent, and reliable fueling method on the N63. However, not everyone has easy access to ethanol which is why water-methanol injection is a popular mod and great alternative.

Risks of N63 Water-Methanol Injection

The power gains and benefits of N63 WMI don’t come without a few risks. Fortunately, many of the risks can be avoided with a good setup and tuning. A good setup can be just as good and reliable as E85 fueling, and I’ll circle back to that point in a moment. For now, let’s discuss the main risks:

• Loss of flow
• Uneven flow

Loss of water-methanol flow is one of the main concerns as these setups are not controlled directly via the DME. It’s a separate tank, pump, injector(s), fuel lines, etc. A sudden loss of WMI can be costly if you don’t have a good setup with a quality controller and tuning. Using fail-safe systems, like the JB4 WMI integration, helps mitigate this risk.

Uneven flow is really the main concern with N63 water-methanol injection kits. Most basic setups spray through 1/8″ NPT bungs in the charge pipes. The flow from the charge pipes into the cylinders isn’t always even. It’s not a huge concern on conservative WMI setups where you mostly want cooling benefits. However, if you’re heavily relying on methanol as a source of octane and fueling then uneven flow can cause serious problems.

Charge Pipe vs Direct Port WMI

Charge pipe methanol injection is the cheaper option. It simply requires aftermarket charge pipes with 1/8″ NPT bungs. You’ll then need the WMI kit with a controller. As mentioned above, charge pipe injection can result in uneven flow. However, that’s not a major concern for those who just want better cooling, a little extra performance, and knock suppression. These kits are the best option for conservative setups that aren’t heavily relying on WMI as a form of fueling.

One of the best ways to avoid uneven flow is running more advanced setups like direct port WMI. Port injection is a common setup for highly modded BMW’s running E85 fuels. These port injection kits can also be setup to run N63 water-methanol injection. Ultimately, it’s an expensive route since it relies on 8 injectors and additional fuel rails to deliver the WMI directly into each intake port. We recommend direct port WMI setups for anyone relying on methanol as a major source of octane and fueling.

N63 Water Methanol Injection Kits

With the basics out of the way, it’s time to discuss some N63 water-methanol injection kits. Unfortunately, options are a little limited on the N63 compared to other BMW turbo engines. However, there are tons of universal kits and options that work well. Let’s jump in and discuss some of the best BMW N63 WMI kits.

1) JB4 Universal WMI Kit

Burger Motorsports is well known in the BMW world for their popular and successful JB4 tuners. They also offer their universal water-methanol injection kit that’s a great option for the BMW N63. The kit starts at $419 and integrates seamlessly with the JB4 making tuning and setup a breeze.

On the N63, we recommend opting for dual BM7 or BM10 nozzles. The smaller BM7 are ideal for conservative setups whereas larger BM10 nozzles are best suited to those needing more flow. There are a number of tank options, including a 2 gallon stealth tank designed specifically for the F10 chassis.

Dual nozzles with the F10 tank comes in at $698 and is an excellent N63 water-methanol injection setup. You can also upgrade to a steel braided hardline for an additional $189. Even with all the options, it’s a good price for a kit that easily integrates with the JB4. Ultimately, if you run the JB4 tuner or plan to run it then this is an easy choice for a WMI kit.

Price: $419-887

Buy Here: Burger Motorsports Universal WMI Kit

2) Boost Cooler Stage 3 WMI Kit

Snow Performance is another brand that offers some great universal N63 water-methanol injection kits. Their Boost Cooler Stage 3 kit comes in at $833.99 and includes a controller, fittings, stainless braided line, pump, a single nozzle and 3L tank. It’s a great kit but will require some additions to run dual nozzles, which we recommend on the N63 (may be required depending on where you spray the WMI).

The 3L tank is also on the small side depending on how heavily you plan to rely on WMI. Ultimately, this is a good standalone kit for anyone who isn’t running the JB4. However, if you’re running the JB4 then we highly recommend the previous kit. Integration is simpler and the dual nozzle setup with the larger 2-gallon tank is a much more convenient solution.

Price: $833.99

Buy Here: Snow Performance Stage 3 WMI Kit