Ford Focus ST Charge Pipe Upgrade Guide
Upgrading the charge pipe on a Focus ST is common practice for increasing airflow from the intercooler to the engine. Fortunately, the engine uses a metal charge pipe from the factory which means cracking or failure isn’t a concern. It is however small and restrictive which is why upgrading it can offer some solid performance benefits. In this guide, we discuss Focus ST charge pipe upgrades, benefits, and power gains.
What is a Charge Pipe?
The charge pipe on the Focus ST bolts up directly to the intercooler and the intake manifold. It is also common referred to as the cold-side intercooler piping. It gets this term because it carries air after the air has been cooled by the intercooler. You’ll also see options to upgrade your hot-side intercooler piping which is the piping that carries air from the turbo to the intercooler. The hot-side piping is also sometimes referred to as a charge pipe as well.
Air that has been compressed by a turbocharged is common referred to as charge air. Therefore, both the hot-side and cold-side pipes are considered “charge pipes” because they carry charge air.
Focus ST Hot-Side Charge Pipe = carries air after its compressed by the turbo to the intercooler
Focus ST Cold-Side Charge Pipe = carries air from the intercooler to the intake manifold
Both pipings are referred to as charge pipes and intercooler pipes which can be somewhat confusing. Most companies will sell them separately but some will sell them as a kit.
The stock charge pipes do not usually fail, but they can blow off under high boost levels. The stock hot side pipe is made of rubber so it can flex and pop off under high boost. So while I wouldn’t say an upgrade is needed for reliability or as preventative maintenance, they are good for ensuring you don’t pop one off while driving down the road.
Focus ST Charge Pipe Upgrade Benefits
Both the hot side and cold side chargepipes are restrictive on the Focus ST. They are completely fine for a stock car. However, once you start to modify the ST with things like an intake and tune they quickly become restrictive. More power requires more air and therefore you need to be able to push more air through the charge pipe.
- 0-5whp and torque power gains (mod dependent)
- Prevents boost leaks and pressure drops
- ~20% to 30% increase in air flow
- Option for meth injection
- Ability to add blow off valve for cool sounds
- Won’t pop them off (added reliability)
Most upgraded intercooler pipes use a 2.5″ and 2.75″ (hot-side, cold-side) aluminum piping which leads to an increase of about 20-30% in airflow over the stock system. Larger piping also causes less pressure drop, which means the larger pipe will help hold boost levels through to the engine. Power gains are probably zero on a stock car, however, they can add some power once you are running a tune, intake, and larger intercooler.
Power gains and benefits are proportional to the amount of air you are flowing. With a tune, intake, and intercooler upgrade we think the pipes are a great add-on. With an upgraded turbo, they are very highly recommended, for example.
Two other additional benefits we’ll touch on quickly: the ability to add meth injection, and the ability to run a blow off valve. Most upgraded ST cold-side chargepipes have a 1/8th inch bung for methanol injection. Additionally, you can get the cold-side piping with flanges for an HKS blow-off valve for the cool “psssh” sounds.
Blow-Off Valve & WMI
The only reason to upgrade the Focus ST hot-side charge pipe is for the increased air flow. The cold-side chargepipe, however, has a few other added benefits. First off, you can get a charge pipe with a flange to run a blow-off valve. There isn’t really any performance benefit or reason for a blow-off valve other than that they sound cool. We love the HKS SSQV because it’s one of the noisier ones you can get on the market and sounds awesome. However, if you think BOV’s sound ricey then you can get a cold-side pipe that uses the stock diverter valve.
Secondly, cold-side pipes have methanol injection (WMI) bungs. The stock fueling system on the Focus ST taps out around 350whp. If you want to push past this power level without upgrading the fueling system, meth injection is the way to go. Additionally, even if you aren’t pushing these levels you can get solid gains out of meth injection.
Is a Focus ST Charge Pipe Upgrade Worth It?
As we mentioned above, charge pipe upgrades probably won’t provide any power on a completely stock ST. Power gains are increased as additional mods are added. If you have a tune, intake, and upgraded intercooler then we would recommend the adding the intercooler piping if it’s within budget. The piping will increase airflow allowing the engine to breathe better, offering better throttle response and preventing boost leaks. If you have an upgraded turbo then the piping is highly recommended.
Overall, it’s worth it if it’s within your budget. It will provide some small power gains but create a healthier engine, prevent any piping from popping off, and make sure you’re transferring the most boost from the turbo to the combustion chamber.
If you want the cool BOV noises or to run WMI meth injection then you need to upgrade the cold-side charge pipe.
Should You Upgrade Your Intercooler First?
Probably. The intercooler and its capacity is the priority. Increasing flow to the intercooler or away from it isn’t really important if the intercooler itself is overwhelmed and can’t support the amount of air flowing to it.
Again, if you can afford buying these with your intercooler we would recommend it. But, they aren’t a priority unless you have an upgraded turbo or are pushing serious boost on an aggressive tune and need maximum air flow.
Best Focus ST Charge Pipes
When upgrading the Focus ST charge pipe you can either upgrade the cold-side pipe, the hot-side pipe, or both. If you want the cool sounds and potential for WMI then upgrade the cold-side. If you want to prevent piping from popping off upgrade the hot-side. We recommend upgrading both if the budget can afford it.
You’ll see various options out there on the cold-side. You can opt for a charge pipe that keeps the stock diverter valves or choose one that has a flange for a blow-off valve. Just keep in mind if you get something with a blow-off valve flange you will also need to buy the BOV. Blow-off valves are about $250 so it can get pricey, considering it’s pretty much just a sound mod.
1) CVF Charge Pipe Upgrade
CVF is one of our favorite EcoBoost performance manufacturers. They offer the best combination of quality, performance, and price that we’ve found on the market. CVF offers a few different options for the Focus ST.
CVF a hot-side piping kit that features a 2.5″ aluminum pipe that fits all stock and aftermarket intercoolers. On the cold-side they have a charge pipe that fits with the stock diverter valve, or one with an HKS flange for those wanting a blow-off valve. Both the cold-side pipes are 2.75″ aluminum and have 1/8th inch meth bungs. If you are looking to buy both the hot and cold side pipes, you can buy one of their kits which saves you about $70 vs. buying them individually.
Overall, CVF is a great brand with a good product offering one of the best bangs for the buck on Focus ST downpipe kits.
Price: $185 to $350 (depending on individual vs kit)
Buy Here: CVF Focus ST Chargepipe Kits
2) Mishimoto Chargepipe Kit
There are dozens of options on the market so we prefer to stick with tried and true brands. Mishimoto is well known for their intercoolers, radiators, and other cooling related products. Their Focus ST chargepipe kit includes both the hot-side and cold-side piping. Mishimoto claims a 21% increase in airflow over the stock piping which sounds reasonable to us.
For $345 this kit comes in at a pretty solid price considering the brand value. The only downside is that the cold-side piping is all silicone. If you don’t care about a BOV or meth injection then this isn’t a problem. However, silicone is a bit less durable compared to the aluminum piping offered in the CVF kit which is likely why the price is a bit more affordable.
Price: $345
Buy Here: Mishimoto Focus ST Intercooler Pipe Kit
Focus ST Charge Pipe Upgrade Summary
Overall, a hot-side and cold-side charge pipe upgrade is a good mod for the Focus ST for those pushing a lot of boost. Power gains aren’t quite there for stock ST’s, but the piping kit begins to provide some small power gains as additional mods are added. Increased airflow through the intercooler is only beneficial if you are bringing a ton of air in through the intake.
If you are upgrading your ST intercooler and can afford the piping, we would recommend getting it. Otherwise upgraded piping is something that can wait until you are running a really aggressive tune and intake or upgrading your turbo.
However, outside of just power gains intercooler piping does offer a few other benefits. More air flow results in a more efficient engine. Additionally, you will notice some better throttle response and a more responsive engine. Cold-side upgrades allow for the addition of a blow off valve for cool induction sounds, and also have meth bungs for those looking to push extra power via meth injection.
If you are in the market for charge pipe upgrades then we highly recommend CVF. They offer one of the most affordable kits on the market without sacrificing quality.