The best mod for the 3.5 EcoBoost F-150, according to our guide, is downpipes, which came in first place. A less restrictive downpipe can have a significant impact on performance and power for the F150 because it is the most restrictive part of the exhaust system.
This guide will cover the advantages of upgrading your downpipes, the differences between catless and high-flow catted downpipes, and the best downpipe manufacturers for your F150. While this guide is geared toward the F150 in particular, it applies to all Fords equipped with the 3.5-liter EcoBoost engine in some way or another.
What is a Downpipe? Ford F150 EcoBoost
Because Ford trucks have only recently begun using turbochargers, we’ll give a quick rundown of what a downpipe is and why it’s so popular with turbo engines.
The turbocharger’s downpipe connects to the exhaust’s cat-back section via a bolted-on downpipe. Although turbocharged engines use downpipes, naturally aspirated engines use headers, which are similar in that they are the first part of the exhaust system to exit the engine.
The primary catalytic converter is usually found in the downpipe of turbocharged engines, and this is the case with the 3.5 EcoBoost as well. Because it connects directly to the turbo and houses the catalytic converter, the exhaust system’s most critical and restrictive part.
Because all of the restriction sits in the downpipe, installing a catback exhaust on your F150 usually won’t result in significant gains in power.
There’s a lot of backpressure created by the restriction in the downpipe and the downpipe’s connection to the turbocharger. Because the pressure creates restriction, the ability of the turbine wheels to spool is hampered by the backpressure.
Pre-turbo pressures should be high, and post-turbo pressures should be low. The most effective way to reduce post-turbo pressure is to upgrade the downpipe.
3.5 Ecoboost Downpipe Upgrade Benefits
- 10-25whp gains
- 10-25wtq gains
- Improved turbo spool and turbo efficiency
- Less backpressure
- Decreased EGT’s (exhaust gas temps)
- Slightly louder exhaust tone
The primary advantage of upgrading your F150’s downpipes is the reduction of exhaust system backpressure. The best exhaust for a turbo engine is one that has no exhaust system after the turbo, but this isn’t possible due to emissions. Due to the primary catalytic converters housed in the downpipes, the exhaust system’s biggest backpressure generator is the downpipes, of course.
When the pressure difference between before and after the turbocharger is greater, the turbocharger spools more efficiently. Post-turbo pressure occurs as a result of the catalytic converter’s restriction, and this reduces the turbocharger’s ability to spool.
By lowering the backpressure, the turbo has less resistance and can spool up more quickly. Most of the power gains come from a more efficient turbo, but a more powerful turbo is also available.
Downpipes’ advantages are multiplied when they’re used in conjunction with a tuned engine and an upgraded intake system.
Gen I vs. Gen II 3.5 EcoBoost Power Differences
The Gen I 3.5 makes 365 horsepower and 420 pound-feet of torque out of the box, while the Gen II makes 375 horsepower to 450 horsepower and 470 pound-feet of torque.
The addition of port injection in addition to direct injection is the primary difference responsible for the increased power. The turbine wheels have been made lighter, and a new electronic wastegate has been installed.
Upgraded downpipes benefit both generations of the 3.5 EcoBoost equally, but the turbocharger upgrades on Gen II engines will result in slightly more power.
F150 Catless vs. Catted Downpipes
Catless or high-flow catted downpipes are the two options for upgraded downpipes. Catless downpipes, as the name suggests, do away with the catalytic converter entirely. To reduce backpressure, choose a catless exhaust system instead of one with one. This results in marginally better power gains because the catalytic converter is the system’s most restrictive component.
Catted downpipes with a higher flow rate keep the catalytic converter, but the higher flow rate is still within legal limits. Due to the fact that they still have a cat, they provide less power gains compared to catless options of about 5-8whp. While the trade-off is that your car will remain legal and will pass emissions tests.
Despite the fact that catted downpipes produce less horsepower, the higher flow rate they provide still outweighs the shortcomings of the stock downpipe.
Because of the recent crackdowns on emissions, it’s best to stick with a catted vehicle. With an upgraded turbocharger setup, we would only recommend the catless option to those looking to make serious gains on the track.
Another advantage of catless downpipes is that they’re more cost-effective. They cost half as much as high-flow catted options because they are hollow pipes without a cat.
Biggest power gains + best bang for the buck = catless.
Emissions legal + still good power gains = high-flow catted.
Best 3.5 EcoBoost F150 Downpipes
Catless downpipes are getting harder to come by because of recent EPA emissions activity. For those seeking used products, forums and marketplaces are excellent resources.
It’s also important to keep in mind that EPA guidelines differ from state to state. Some states, like California, consider catted downpipes to be illegal, so be sure to check your state and local regulations before making any downpipe upgrades.
Despite the fact that most catalytic converters are EPA-approved, in some states, they are still illegal.
Best Catted Bang for the Buck: SPD Performance F150 Downpipes
With a price tag of $795, SPD Performance’s downpipe is our pick for the best value. It’s a great option for those who want a high-flow catted option but don’t want to spend $1,300 on a downpipe.
In comparison to the factory downpipe system, SPD’s 3′′ piping and high-flow, EPA-approved catalytic converters are a significant improvement.
Budget Breaker: AMS Performance F150 High-Flow Downpipe
There’s an AMS downpipe for the 3.5 EcoBoost F150 from top to bottom. As the most expensive option on the market at $1,800, it’s built for racing and high-powered use only.
The AMS downpipes offer the highest flow and most backpressure reduction on the market with 3′′ piping and a 25% increase in inlet surface area.
Catless Option: aFe Power F150 Downpipes
aFe Power makes a 3′′ catless option for those who prefer it. Compared to catted downpipes, which cost around $500, these downpipes have more flow and less backpressure.
These downpipes, on the other hand, are made of aluminized steel, not stainless steel as you might expect. As a result, downpipes made of this material will corrode and wear out more quickly in wet climates than those made of stainless steel would.
This downpipe does have one flaw: it lacks a cat, making it illegal. As a result, finding them for sale online is becoming increasingly difficult, as the majority of aftermarket performance part suppliers have stopped selling catless products online.
There are a lot more catless downpipe options on eBay, which is something to keep in mind. If you decide to go that route, be sure to check the piping’s fitment before buying. Because catless exhaust systems are essentially just hollow pipes, going with a less expensive model from eBay will have no negative consequences for your vehicle’s performance.
F150 3.5 EcoBoost Downpipe Summary
One of the best modifications you can make to your EcoBoost 3.5 F150 is to upgrade the downpipe. Higher-flowing downpipes, when used in conjunction with a tuned intake and an upgraded intake system, can significantly improve performance by increasing turbo efficiency.
Compared to high flow options, catless engines will be noisier and produce 5 to 8 fewer horsepower. Most states, with the exception of California and New York, have legalized high-flow catted options.
Neither the catless nor the catted exhaust systems will produce obnoxiously loud noises when driving. Unless you add a full cat-back system with downpipes, you should only expect modest acoustic improvements.
Downpipes are a worthwhile investment for 3.5 EcoBoost F150 owners looking to boost output.