Top 5 Ford 4.6 Performance Upgrades

For many years, the Ford 4.6 V8 engine was one of the most powerful engines in the Ford lineup. Producing north of 300 horsepower and 300 lb-ft of torque in performance models like the Mustang GT and SVT Cobra, it is capable of laying down some serious rubber. Ford also put the engine in non-performance models like family sedans and SUVs. For those of you looking to get a little more horsepower out of your 4.6 V8 you’re in the right place, because today we’re talking about the top 5 Ford 4.6 performance upgrades.

Whether you have a SVT Cobra or Bullitt Mustang, or just want to make some extra power with your Expedition or Explorer, the Ford 4.6 is a great engine for modding. No matter what model you have, just a few upgrades can net some solid horsepower and torque bumps. In this article, we’re going to look at the best mods for any Ford 4.6 owner, including those with the supercharged SVT Cobras. We’re evaluating for practicality, price, quality, and most importantly, performance. Let’s get started.

Ford 4.6 Engine Info

Ford produced the 4.6 modular V8 from 1991–2014, putting it in nearly 20 different models between the Ford, Lincoln, and Mercury brands. It is a 4.6 liter V8 engine, with an aluminum head and both cast iron and aluminum blocks. There are three different versions of the 4.6 Ford V8; a 2-valve SOHC, 3-valve SOHC, and a 4-valve DOHC. Of all of them, the 4-valve offers by far the best performance (check the linked engine guide above for a full list of 4-valve 4.6 Ford vehicle applications).

The bore and stroke are 3.55 in × 3.54 in (90.2 mm × 90.0 mm), making it an almost perfectly square engine. Both the SOHC and DOHC engines have two different factory cylinder heads, as well as an available Ford Performance cylinder head with superior flow characteristics. All Ford 4.6 engines use electronic fuel injection, and the 3-valve versions use Variable Camshaft Timing (VCT).

From 2003–2004, Ford released the “Terminator” version of the 4-valve engine, which many consider one of the best Ford engines ever made. It produced 390 horsepower and 390 lb-ft of torque, courtesy of an Eaton M112 roots-type supercharger running 8 psi of boost. Even today, the Terminator 4.6 Ford Mustang is highly revered, and examples routinely go for more than $50,000 for well taken care of versions.

Top 5 Ford 4.6 Performance Upgrades

Our top 5 Ford 4.6 performance upgrades are:

• ECU Tuning
• Cold Air Intake
• Long-tube Headers
• Blower and Underdrive Pulleys
• Throttle Body and Upper Plenum

No matter what 4.6 Ford V8 powered vehicle you drive, these are by far the 5 best Ford 4.6 performance upgrades. First up, we have ECU tuning. ECU tuning is one of the easiest, simplest, safest, and most cost-effective ways to add power to your car. As we’ll explain more below, tuning can net upwards of 20-30 horsepower alone. It can also help compensate for other bolt-on mods installed on the car, like headers and intakes.

After ECU tuning, we suggest making adjustments to increase the amount of airflow in and out of the engine. The easiest way to do that is to upgrade the intake and exhaust. An upgraded cold air intake will allow your engine to consistently take in cool air. Long-tube headers will replace the heavy and inefficient cast-iron manifold with better flowing stainless steel pipes. Both will add horsepower and volume to your engine.

After tuning and airflow, another pretty cost-effective modification is to upgrade your supercharger and/or underdrive pulleys. If you have a Terminator 4.6 V8, upgrading the blower pulley frees up lots of horsepower and is very easy to install. Underdrive pulleys also free up horsepower and are very cheap and easy to install, too.

Finally, we recommend upgrading the throttle body and upper plenum. These are by far the most restrictive part of the intake system besides possibly the air filter. Upgrading them is a must before trying to step up in power levels.

Now, let’s take a look at all of these Ford 4.6 performance upgrades in-depth.

1) Ford 4.6 Performance Upgrade: ECU Tuning

First on our list of top 5 Ford 4.6 performance upgrades in ECU Tuning. Your ECU is your engine control unit, and it is the computer that essentially controls how your engine functions. Just by tuning your ECU, you can add a good 10-20% increase in power over stock, and that’s without any hardware or bolt-on modifications.

To comply with emissions regulations and to make sure their engines last as long as possible, most car manufacturers deliberately undertune their vehicles – even the high performance models like the SVT Cobra – to make less horsepower and torque than they otherwise could. With ECU tuning, a qualified tuner can unlock some of this hidden horsepower by making adjustments to things like ignition timing, camshaft timing, air-to-fuel ratios, and boost pressure (if you have a supercharger equipped).

In addition, tuning can also help your engine run safely when bolt-on and hardware modifications, like cold air intakes and long-tube headers, are added. Many bolt-ons change the airflow in the engine, which the ECU can struggle to compensate for. Though many of them claim to still maintain safe air-to-fuel ratios, the only way to be sure is to have your ECU tuned.

Your tuner can monitor for things like engine detonation (knock) or pre-ignition, to make sure your engine is running healthy and optimally. Tuning also helps you squeeze more power out of your bolt-on and hardware modifications.

Best Ford 4.6 Performance Upgrades for ECU Tuning

As far as the Ford 4.6 V8, you have a couple of different options for tuning. These are known as custom tuning or canned tuning. Custom tuning is the better option of the two, because it involves a tuner making adjustments based on your specific car in your atmospheric conditions.

Canned tunes are instead more like one-size fits all tunes that are meant to work for a specific model of car. While they are specific to the car, they are less precise than custom tuning because they are not adjusted to your specific vehicle with your environmental conditions. Obviously, someone living in Florida and someone living in Seattle are going to have completely different atmospheric conditions. So to truly optimize your car for your mods and climate, you need to go custom.

Custom tuning is best done in-person on a dynamometer, which are usually found at local performance shops. E-tuning is also an option, where you correspond with a tuner by email. But unless you have a Mustang, it’s going to be difficult to find a custom e-tuner.

For canned tuning, we recommend Unleashed Tuning and 5 Star Tuning. They are a compromise between canned and custom tuning, as they offer customized tunes but don’t make specific adjustments for your car. They are not as good as a custom tune on a real dynamometer, but they are a close second.

Regardless of custom or canned tuning, you will need some kind of tuning hardware device to transfer the tune to your car. Some of the most popular are the SCT and DiabloSport. We highly suggest finding your preferred tuner first, and then purchasing whichever tuning hardware they recommend. Keep in mind, not all tuners use all tuning devices.

2) Ford 4.6 Cold Air Intake Upgrade

Next on our list of top 5 Ford 4.6 performance upgrades is a cold air intake. Cold air intakes are probably the most common and popular upgrade you can make to the 4.6 Ford. Cold air intakes work by rerouting the air intake filter towards the fenderwall and away from the engine bay. This allows them to take in cooler and colder air. The colder the air the more oxygen it has, which means your engine can make more power, get better gas mileage, and work more efficiently.

Additionally, cold air intakes usually have larger air filters and tubing than the stock intake does. This means they can take in more air than stock, which is crucial if you want to add power. Upgraded intakes also generally add more sound to the engine to make it louder. They also really spruce up the engine bay, giving it much more of a race aesthetic.

Another intake option is a ram air intake, but these aren’t always good choices. Ram air intakes work by providing the quickest and least resistant path for incoming air. It won’t usually bring in colder air, but it does eliminate restriction and increases flow.

While the stock intakes generally perform okay, if you add any other bolt-ons like long-tube headers it often becomes a restriction point. Adding a freer flowing intake will improve throttle response, top-end power, and increase the engine noise.

Top Ford 4.6 Cold Air Intakes

From the factory, most 4.6 V8 powered Ford, Lincoln, and Mercurys actually already have cold air intakes. The air filters are located near the fenderwall and away from the engine bay, where they can take in relatively cool air.

The point of getting an upgraded cold air intake is to reduce restriction, increase tubing diameter, and route the filter even further away from the engine bay. The factory air box is heavy, and the tubing is relatively restrictive and usually made of cheap plastic. Upgraded intakes usually have an open air box, change the panel filter to a cone filter, and have wide diameter and better piping. All of this equates to better airflow due to the reduced restriction.

Due to the use of a cone instead of panel filter, upgraded intakes can also be placed closer to the fenderwall. Though the difference is somewhat minimal, it does help keep the hot air from the engine bay further away.

Our recommendation for Ford 4.6 cold air intakes is from 5 Star Tuning. They offer intakes for a huge variety of 4.6 powered Fords, including Crown Victorias, Mustangs, and E-series vans. Most of them use quality K&N air filters, and they are all pretty reasonably priced.

Keep in mind, the Ford 4.6 engine uses a MAF based system for measuring airflow. Without getting too complicated, this means that you will want to invest in custom tuning if you upgrade your intake. Make sure you have a tuner in mind before purchasing and installing any upgraded intakes.

3) Ford 4.6 Long-tube Headers

Third on our list after ECU tuning and cold air intakes is going to be long-tube headers. On the Ford 4.6 V8, the OEM headers are built from heavy and restrictive cast iron. This makes them terrible in terms of optimal flow, and also makes them very prone to cracking after repeated heat cycles. For any build, even small ones, upgrading your headers is an absolute must. Since the Ford V8 uses two cylinder banks, it also uses two headers, one per bank.

The purpose of long-tube headers is to replace the OEM exhaust manifold (also called headers) back to the mufflers. Typically, aftermarket headers are manufactured from T304 stainless steel, which is lighter than cast iron but very strong. They are also designed to facilitate the best and least restrictive flow possible. Long-tube headers also replace the factory catalytic converters, which are by far the biggest choke point of the exhaust.

Long-tube headers work by reducing back pressure and reversion, while increasing exhaust scavenging. The reduction in back pressure allows for better exhaust flow. Increased exhaust scavenging and reduced reversion means exhaust gasses are removed quicker and more clean air can enter the combustion chamber. This leads again to bigger and more sustained power.

You’ll also undoubtedly get a big bump in exhaust volume from long-tube headers. As you might expect, the big increase in piping and optional cats also really turns up the sound from the Ford 4.6 V8.

Top Ford 4.6 performance upgrades for long-tube headers

When looking at long-tube headers for a 4.6 powered Mustang or other vehicles, you’re going to have two options: catted or catless. While catless systems will produce a little more power, they are also not emissions compliant and will not pass inspection. We recommend going with catted headers, because the power difference is pretty minimal and they are better for daily drivers. They still flow well enough to meet most power goals, and seriously cut down on the awful catless emissions smells.

You may have also heard of short-tube or “shorty” headers, but we generally recommend against those, too. They only replace the very front part of the exhaust manifold, before the cats, and do not add much power. If you want to upgrade your exhaust, it’s really long-tube or bust.

There are many different manufacturers for long-tube headers, so your best bet is to stick with a reputable company, like Magnaflow, Borla, Corsa, Kooks, or American Racing Headers. If you have a 4.6 Mustang and want to upgrade the long-tube headers, American Racing Headers makes several solid options. They have 2, 3, and 4-valve options available for any 4.6 powered Mustang you have. They have a solid reputation in the industry, and their headers are guaranteed to look and perform outstanding.

4) Ford 4.6 Blower and Underdrive Pulley Upgrade

Next up is going to be upgrading the pulleys on your Ford 4.6 V8 powered vehicle. Depending on the model you have, you’ll want to either upgrade your supercharger pulley or underdrive pulley (or both).

Supercharger (blower) pulleys work by making your supercharger pump out more boost. Superchargers are run by mechanical drives, usually serpentine belts, that are spun by the crankshaft. These belts are connected to pulleys, the size of which directly determines how fast the supercharger runs. The smaller the pulley the faster the supercharger runs, which increases the amount of boost it pushes out. More boost means more power, and blower pulleys can net usually anywhere from 30-40 wheel horsepower.

Underdrive pulleys have a similar but different method of increasing horsepower. On many 4.6 powered Fords, the crankshaft pulley drives the accessory belt, which includes things like A/C, the water pump, and alternator. The purpose of an underdrive pulley is to reduce the parasitic drain from the accessory belt on the engine. It does so by slowing down the accessory belt, which reduces the amount of power it needs. Instead of the power being wasted on the accessory belt, it can be sent to the wheels.

Top Ford 4.6 Supercharger and Underdrive Pulleys

The top options for upgrading the supercharger and underdrive pulleys on your 4.6 powered Ford are both from Steeda. Steeda has a very solid name in the Ford and Mustang performance industry, and they have been in the game for many years.

The Steeda supercharger pulley comes in two sizes, 3.10” and 2.81”. The larger pulley is good for a 1-2 psi increase in boost pressure and 25+ horsepower increase. The smaller pulley is good for a 4-5 psi increase in boost pressure and 60+ horsepower increase. Importantly, the smaller pulley will also require a smaller serpentine belt to hold proper tension.

The Steeda underdrive pulley claims the ability to slow down the accessory belt by a solid 25%, which results in an increase of 5-10 horsepower. You will also see a 2-3 mpg increase from installing an underdrive pulley.

5) Ford 4.6 Throttle Body and Upper Plenum Upgrades

Our final recommendation for the top 5 Ford 4.6 performance upgrades is the throttle body and upper plenum. Within the intake system, besides possibly the intake filter, the throttle body and upper plenum of the intake manifold are the most restrictive parts. The throttle body sits between the intake manifold and air intake itself. The upper plenum is the uppermost part of the intake manifold.

The stock throttle body measures to 65mm, which is slightly undersized for an engine as large as 4.6 liters. Aftermarket throttle bodies are larger than stock, usually by minimum 5-10 mm, which allows them to take in more air. Additionally, the upper plenum on the manifold is very restrictive, so porting it allows it to take in more air. Porting is a process where the metal is smoothed over to promote airflow and reduce turbulence.

Top Ford 4.6 Throttle Body and Upper Plenum Upgrades

By far, the top of the line upgrade for the Ford 4.6 V8 throttle body and plenum is the Accufab unit. Accufab has both 70 mm or 75 mm options for the throttle body, increases of 5 mm and 10 mm over stock. These will allow for greater airflow, resulting in 5-8 horsepower increase.

The Accufab unit can be had with or without the upgraded upper plenum, but we recommend getting it. The ported plenum will allow for much better airflow over stock, and if you are upgrading the throttle body it’s a no-brainer to do the plenum at the same time. Unless you have a 4-valve 4.6 Ford V8, in which case it is not as big a restriction point.

Together, you should see gains of 10-15 horsepower, as well as an increased power band.

Top Ford 4.6 Performance Upgrades Conclusion

Overall, the Ford 4.6 V8 is a very solid engine that responds very well to upgrades. Whether you have a naturally aspirated version or the supercharged Terminator Cobra, adding some simple mods can really transform the engine.

To start with, we recommend doing basic ECU tuning to get a healthy power increase without having to do any hardware or bolt-on modifications. If ECU tuning isn’t quite enough for you, the next step is upgrading the cold air intake and long-tube headers. These are two of the most popular modifications to make, and they will add serious power and volume to your Ford 4.6.

After the ECU and intake/exhaust, your next stop should be looking at supercharger or underdrive pulleys. These are very cost-effective ways to get decent increases in horsepower, especially the supercharger pulley. Finally, our last recommendation for Ford 4.6 performance upgrades is to get a larger throttle body and ported upper plenum. These will add 5-15 horsepower, and really allow your engine to suck in some serious air.

There you have it, if you’re looking at modding your 4.6 powered Mustang, Explorer, Expedition, or any other model, this is where you should start. Let us know your thoughts in the comments below!