The 5.9 Cummins is legendary in the diesel world for many reasons. However, by modern diesel standards it’s a bit lacking in power and torque. Fortunately, the Cummins 5.9L diesel engine has plenty of untapped potential. A few basic mods can truly take it to the next level. Among the best upgrades for the 5.9 6BT and ISB engines is an intake manifold. In this guide, we discuss 5.9 Cummins intake manifold upgrades, benefits, horsepower gains, and more.
*We’re focusing on both the Dodge Ram 5.9 12v and 24v engines in this article. Fitment varies and the exact hp results and other data can vary based on a lot of external factors.
5.9 Cummins Intake Manifold – What Is It?
An intake manifold is pretty simple, so we won’t spend much time here. It’s simply the part of the engine that supplies air to the cylinders. As such, it bolts up directly to the cylinder head. However, there are several different names that refer to the 5.9 Cummins intake manifold.
You may see upgrades referred to as 5.9 Cummins intake horns or intake elbows. It’s essentially just an intake manifold. The various names are mostly due to the design. If you’ve seen a normal intake manifold you’ll notice the Cummins manifold design is rather unique. There are not 6 runners going to each cylinder. Instead, it’s simply a single large tube that flows into the cylinder head.
5.9 Cummins Intake Horn Benefits
A few benefits of an upgraded 5.9 Cummins intake manifold include:
- 10-25+ horsepower gains
- 20-40+ torque gains
- Even more gains down low
- Lower EGT’s
- NPT Ports
We’ll break down the power gains below since there are different variations of manifold upgrades. Anyways, the gains are certainly promising for a simple bolt-on mod. Another excellent benefit is reducing EGT’s. It’s not uncommon for 5.9L Cummins EGT’s to drop by about 50-200°F with an intake horn upgrade.
An aftermarket manifold will typically include 1/8″ NPT ports. These are useful for running boost gauges, water/methanol injection, and tons of other options. Some may consider an intake manifold upgrade for the NPT ports alone.
Various 5.9L Diesel Manifold Designs
There are a few different 5.9 Cummins intake manifold mods you’ll come across. The most common option is simply sticking with the same design as OEM. Again, this is just one large tube flowing air into the cylinder head. Next are the twin intake horns, which actually split into 2 runners. Lastly, you can modify the 5.9 Cummins to accept a “standard” manifold with 6 individual runners to each cylinder.
Depending on your goals and needs one option in particular may be the best bet. As such, let’s jump in and compare each 5.9 Cummins intake horn design along with benefits and cons of each.
5.9 Cummins Intake Horn/Elbow Upgrade
If you’re looking for the simplest and cheapest option then sticking with the OEM intake horn design is your best bet. These upgrades offer great benefits for the cost including:
- 5-15+ horsepower
- 15-25+ torque
- Other benefits discussed above
- Easy to install
You’ll get the basic benefits with the 5.9 Cummins intake horn upgrade. The intake manifold isn’t likely to add much power on lightly modded trucks. However, with a tune and other simple bolt-ons you can expect about 10-15hp and 15-25+ torque. The gains in the lower RPM range are generally even more impressive.
Most single tube 5.9 Cummins intake manifold mods will run about $150-350. It’s also a simple bolt-on install making this an excellent upgrade for the price.
Cummins Diesel Twin Manifold Mods
Those looking for better flow and performance should consider twin intake manifolds – also sometimes known as twin ram manifolds. Benefits of running a twin intake manifold on the 5.9L inline-6 Cummins include:
- 10-20+ horsepower
- 20-35+ torque
- Better air-flow distribution
- Better EGT’s
- More expensive
You can expect to pick up about 5hp and 5-15tq more than the single tube manifold designs. Much of this is due to improved air-flow to all cylinders. The 2 runners provide better distribution of air and can help further lower EGT’s.
5.9 Cummins twin horns usually run in the $500-750 ballpark, so it’s about 2-3x more expensive. Many kits will require you delete the grid heater to install the twin manifold. It’s still a fairly simple upgrade, but if you’re not looking for overkill then the standard single tube may be the best option.
Ram 5.9L Full Runner Intake Manifolds
Complete intake manifolds are best suited to serious builds looking for massive power gains. These will only fit the 2003-2007 common rail 24v Cummins engine. Benefits of opting for these “racing” manifolds include:
- Best power gains (15-20+ hp & 30-50+ tq)
- Best air-flow distribution
- Enables porting of intake ports
- Requires custom work
Compared to other 5.9 Cummins manifold upgrades these options will offer the best flow and performance. The massive air-flow potential is also well suited to porting the 5.9L diesel intake ports. It’s going to require some custom work to install, though. They’re also generally $1,000+, so it’s not a great option for those just looking for simple, cheap power gains.
Best 5.9 Cummins Intake Manifold Upgrades
With all the benefits and basic info out of the way let’s move onto some of the best 5.9 Cummins intake manifold mods. We’ll cover a couple options for all of the different fitments since we’re covering the 12v and 24v Cummins. Please note – this is far from an exhaustive list. Tons of great options exist and we don’t have the space to cover everything.
Instead, we’re simply listing a few manifolds we believe offer the best balance of price, quality, and performance. Check fitment before purchasing anything as certain manifolds may only be available for the 12v or 24v Cummins.
1) 5.9 Cummins Pusher 3″ Steel Intake Manifold
First up is Pusher Intakes with their 3″ steel intake manifold. They’re one of the most common manifold upgrades for the 5.9 Cummins 12v and 24v. These Pusher manifolds are common for many good reasons. One, if you just want the manifold it starts around $175-200. That’s a great price for what’s an awesome looking product with proven results and good quality.
It can get a little more expensive if you want the extra intake plumbing for even better flow. Choose the manifold and intercooler piping kits if you’re looking to maximize performance gains. Anyways, not much else to say about 5.9 Cummins Pusher Intakes. It’s a good product, at a great price, and from a company that’s been selling these for a while. Tough to go wrong here.
2) 5.9L Diesel Amazon Budget Intake Horns
Alright. Some people will likely be scared away from these Amazon options immediately. That’s understandable. However, a 5.9 Cummins single tube intake horn is a simple product. As long as fitment is OK and the welds hold up then there’s nothing wrong with going cheap.
If you’re on a budget check out some of the 5.9 Cummins intake manifold upgrades on Amazon. We were able to find a few options with a quick search for any Cummins from 1994-2007. Don’t expect the same quality as name brand products like Pusher Intakes, Banks Power, etc. At least Amazon makes returns easy if there are any issues. These just might be a good option if you’re looking to save some money.
Buy Here: 2003-2007 Black Intake Elbow Tube
3) Crazy Carl’s Cummins Dual Intake Manifold
The Crazy Carl’s twin 5.9 Cummins intake manifold is the best looking product we could find for the price. It starts at $345 but that’s just for the twin horn. You’ll also need 2 grid heaters or 2 spacers as well as the dual inlet base plate. Add in all that and you’re looking at $600+. It’s still a good price for a twin 5.9 Cummins intake horn.
Anyways, you can choose between 15+ different colors. There’s also options for XL 3.5″ piping, additional NPT bungs, and more. Whether or not it’s worth the extra money for a twin intake is up to each person. It’s definitely a lot more expensive for diminishing gains, but if you’re set on a twin system then look no further. Banks Power also has some good options.
Buy Here: Crazy Carl’s Twin Intake Horn Upgrade
4) Banks Power Racing 5.9 Cummins Intake Manifold
Price: $1,039 (+ customer fitment / install)
Fits: 2003-2007 (24v common rail)
Last up is the Banks Power Racing intake manifold (pictured at the beginning of this article). It fits the 2003+ 5.9 Cummins with Bosch common rail injection. This intake manifold is going to offer the best flow and performance gains on the list. However, it’s really not worth the price unless you’re really pushing things far.
Those who don’t have crazy, high horsepower builds likely have no reason to opt for the Banks Power Racing manifold. Banks is a well known brand and they build some awesome stuff. As such, if you have big goals for your common rail 24v then check out this manifold.
Buy Here: Banks Power 5.9 Cummins Intake Manifold
Dodge Ram 5.9 Diesel Intake Horn Summary
By modern standards the 5.9 Cummins is a bit lacking on factory horsepower and torque. However, this legendary engine has tons of potential in the aftermarket world. Intake manifold upgrades – also known as horns or elbows – are among the best simple bolt-on mods for the 5.9L inline-6 diesel.
Benefits include impressive power and torque gains, especially in the lower and mid RPM ranges. Many also notice EGT drops of 50-100°+. Top that off with 1/8″ NPT ports for gauges & water-methanol injection and a 5.9 Cummins intake manifold has a lot to offer.
Pusher Intakes is a really common option and they have an intake manifold for just about every 12v & 24v 5.9 Cummins. Those on a budget might like some Amazon options, but beware of poor fitment or welds. Crazy Carl’s has an awesome twin intake manifold for 94-98 12v 5.9 Cummins engines. Lastly, Banks Power has options for most trucks but we focused on their interesting complete racing manifold.
What’s your experience with 5.9 Cummins intake horn upgrades? Are you considering one?
Leave a comment and let us know!