Once you achieve the initial level of power gains with your MazdaSpeed 3 that we discussed in our MazdaSpeed 3 Stage 1 Upgrade Guide, it is likely that you will be interested in getting even more. However, proceeding onto stage 2 requires a significantly higher level of caution and skill to accomplish safely and successfully. In addition, component choice at this point is even more important, since it is that much easier for something to go wrong.
- Stage 2: ≈60-100whp
- High Pressure Fuel Pump
- Because the MazdaSpeed 3 has a direct injected engine, it has two fuel pumps, a high pressure pump that supplies the injectors and a low pressure feeder pump.
When aiming for significant power over 300whp, the stock high pressure fuel pump is unable to supply enough fuel at a high enough pressure. This has the effect of making the fuel injectors stay open for too long, and may even cause dangerously lean conditions due to fuel starvation. If the injectors are kept open for too long, they are more likely to burn out and will need to be replaced. To solve this problem, Velocity Factor recommends an upgraded high-performance fuel pump. The one that we have had the most success with is the CPE MZR DISI HPFpump for the MazdaSpeed 3. This pump utilizes the stock pump core, and completely replaces the internal components with high-performance grade parts. Each pump is then tested and precisely broken in on CPE’s test rig and is shipped to you with a complete report which shows exactly what the newly upgraded pump is capable of. Because it utilized the stock pump core, installation is simple. Because this pump is of such high quality, CPE is able to offer it with a lifetime warranty. - High-Flow Cat and Downpipe
- The downpipe and factory catalytic converter is the most restrictive portion of the exhaust, and has a lot of potential for power increase when replaced with a quality MazdaSpeed 3 performance dow
npipe. When dealing with the MazdaSpeed 3 specifically, the downpipe is one of the most sensitive components. When replacing the downpipe on the MazdaSpeed 3, it is very important to pick the right brand. In our experience, we have actually seen the turbo get damaged when the proper downpipe wasn’t used. We have found that the Cobb 3” Downpipe for the MazdaSpeed 3 is the best option. One of the main things that sets Cobb downpipe for the MazdaSpeed 3 apart from the others is the positioning of the O2 sensor. Other downpipes do not have the O2 sensor properly positioned, and this results in calibration problems within the ECU. Over time, this can lead to significant damage to the turbo. The Cobb Downpipe also has a custom high-flow cat that is specially designed for this application and works very well. We have found that the MazdaSpeed 3 engine needs to have a cat installed on the downpipe. If it does not have one, the turbo tends to fail over time. - Upgraded Intercooler
- Just as the downpipe is the most restrictive part on the exhaust side, the factory intercooler can be the most restrictive component on the inlet side. Furthermore, because the factory intercooler is top-mount, it is more prone to heat-soak. The restriction in the factory intercooler reduces flow. The heat-soak and inherent inefficiency of the intercooler increase the charge temperature of the incoming air. The higher temperature reduces the density of the air, which reduces how much oxygen gets into your engine. The lower flow reduc
es this even further. The solution to this problem is to install an upgraded performance intercooler. This can sometimes be an expensive proposition, so Velocity Factor has a couple suggestions that can fit various budgets. We have had very good success with the ETS TMIC MazdaSpeed 3 Top-mount Intercooler. The ETS Top-mount Intercooler features an efficient bar-and-plate intercooler core and has a bolt-on design which utilizes the factory mounting points. This makes for a significantly simpler installation. It is available in 5 
anodized colors to fit your specific color scheme. For those who have a larger budget to work with, we highly recommend upgrading to a front mount intercooler kit. The advantage of this type of design is that it significantly reduces the amount of heat-soak that the intercooler will be exposed to. We recommend the CPE MazdaSpeed 3 Delta-Core Front Mount Intercooler kit. This kit features CPE’s own Delta-Core intercooler, custom silicone upper radiator hose, and a new larger capacity power steering cooler. CPE has put a lot of time and money into the design and testing of this kit. They have published a very detailed white-paper about their intercooler kit. We recommend you read it before investing any of your money into an intercooler upgrade. Another good option that has given us good results is the Cobb Front Mount Intercooler Kit for the MazdaSpeed 3.