F-150 3.5L EcoBoost Stage 1 Build: Intake, Tune, and Cat-Back (2017-2020)

A "Stage 1" build on the 3.5L EcoBoost follows the same logic as the site's 5.0L Stage 1 guide -- three bolt-ons, nothing that opens up the engine, nothing that needs a lift: an intake, a tune, and a cat-back. The 3.5L is a twin-turbo V6, not a naturally aspirated V8, so the numbers behave differently -- turbocharged engines typically see bigger tune gains than naturally aspirated ones, because the tune is often raising boost and adjusting the wastegate, not just timing and fuel.

What you're starting with

This build targets the 2017-2020 F-150's 3.5L EcoBoost (the second-generation twin-turbo V6 in this truck body), rated by Ford at 375 hp and 470 lb-ft at the crank.

The three parts in this build

Cold air intake

A cold air intake swaps the factory air-filter box for a larger, less restrictive filter and housing that pulls in cooler air from outside the engine bay instead of hot underhood air.

aFe's own site states a claimed 32% flow increase and a 22 hp / 26 lb-ft gain for this specific SKU (aFe part 51-73115, the closed-box design) -- a manufacturer claim, not an independent dyno test. One thing worth knowing before you buy: aFe sells a different intake part number for 2015-2016 trucks (54-73112-1) and a different one again for the 5.0L V8 (54-73114) -- make sure the listing you're buying from has the 2017-2020 3.5L-specific part number, not a lookalike.

Tune

A tune is new software for the engine computer, usually loaded through a handheld device that plugs into the port under the dash -- no wrenching involved. MPT's own site publishes a chart for this exact tune showing a stock truck at 307 hp / 344 lb-ft rising to 449 hp / 473 lb-ft on their 93-octane calibration -- a claimed gain of about 142 hp and 131 lb-ft. That's MPT's own dyno chart, not an independent third-party test, and on a turbocharged engine a tune can safely claim a much bigger number than it could on a naturally aspirated V8 because raising boost does real work, not just fuel and timing changes.

Cat-back exhaust

A cat-back exhaust replaces everything from the catalytic converters back with larger piping to change sound and flow.

Be skeptical of this one's number specifically: the +13 hp / +18 lb-ft claim on file for this part comes from an Amazon listing citing an "in-house dyno," not from aFe's own product page directly. It's recorded here because it's the sourced figure on file, but treat it as a retailer's claim rather than a confirmed manufacturer number until it shows up on afepower.com itself.

Suggested install order

There's no mechanical dependency between these three -- the intake and cat-back are both independent bolt-ons. A practical order:

1. Cold air intake
2. Cat-back exhaust
3. Tune, loaded last

Same reasoning as the 5.0L guide: doing the physical parts first means the truck is in its final hardware state before you spend time getting used to how the tune drives.

What to expect

Of the three claimed gains here, the tune's 142 hp / 131 lb-ft is the biggest number and the one with the clearest sourcing (MPT's own published dyno chart for this exact application). The intake's 22 hp / 26 lb-ft is also manufacturer-published. The cat-back's 13 hp / 18 lb-ft is the weakest-sourced of the three -- a retailer claim, not confirmed by aFe directly -- so don't lean on it. None of these three claims were tested together as a stack on one dyno, so don't add them up and expect the total to hold on your truck.

FAQ

Is this the same as the 5.0L Stage 1 build?

Same idea -- intake, tune, cat-back, no internal engine work -- but different parts, different truck, and different numbers. The 3.5L EcoBoost is turbocharged, so its tune gain (142 hp claimed here) runs bigger than the naturally aspirated 5.0L's tuned gains, because boost does more of the work on a turbo engine.

Do I need HP Tuners or a PCM unlock for a 2017-2020 truck?

No -- the locked-PCM issue that affects 2021+ Fords and requires an HP Tuners MG1 unlock service doesn't apply to 2017-2020 trucks. The MPT tune above loads through a standard handheld device with no separate unlock step.

Will any of these affect emissions compliance?

Neither the intake nor the tune's product pages state a CARB or 50-state-emissions-legal status on the pages sourced for this guide -- if that matters in your state, confirm directly with aFe or MPT before buying rather than assuming either way. The cat-back sits downstream of the catalytic converters and doesn't touch emissions hardware the way a header or downpipe would.