Do Cold Air Intakes Really Add Horsepower? We Dyno Tested Them on Three 5.7L Hemis
Cold air intakes are probably one of the most popular first modifications made to a performance vehicle. They’re relatively easy to install, they make the engine sound better, and manufacturers often advertise increased horsepower and torque.
But do they actually make more horsepower?
At Dynomite Performance, we prefer to answer questions like this with real dyno testing.
Over the years, we’ve tested aftermarket cold air intakes on several 5.7L Hemi-powered vehicles using our DynoJet chassis dyno. This gives us an opportunity to compare what happened before and after changing the intake instead of relying solely on advertised horsepower claims.
For this comparison, we’re looking at three vehicles we’ve tested:
- 2019 Ram 1500 5.7L Hemi
- Dodge Magnum RT 5.7L Hemi
- Dodge Charger 5.7L Hemi
The results weren’t identical—and that’s exactly what makes them interesting.
Test #1: 2019 Ram 1500 5.7L Hemi
We started the Ram with a baseline dyno run before installing the K&N cold air intake.
Stock
304 wheel horsepower
331 lb-ft of torque
After installing the K&N intake, we put the truck back on the dyno.
K&N Cold Air Intake
325 wheel horsepower
342 lb-ft of torque
That’s a difference of:
+21 wheel horsepower
+11 lb-ft of torque
That’s approximately a 6.9% increase in peak wheel horsepower compared with our baseline.
For a relatively simple bolt-on modification, we were impressed with the result on this particular truck.
What About a Muffler Delete?
We also tested the truck after a muffler delete.
The result was:
323 wheel horsepower
348 lb-ft of torque
In other words, we didn’t see an additional peak horsepower gain from the muffler delete in this test. Peak horsepower actually measured 2 HP lower than our K&N run, although peak torque increased.
That’s an important example of why we like testing modifications instead of assuming that every change will automatically make more horsepower.
We later tested an Edge Pulsar performance tune.
Edge Pulsar Performance Tune
335 wheel horsepower
356 lb-ft of torque
Compared with our original stock baseline, that’s:
+31 wheel horsepower
+25 lb-ft of torque
Test #2: High-Mileage Dodge Magnum RT 5.7L Hemi
Our second example is particularly interesting because this wasn’t a low-mileage car.
This Dodge Magnum had more than 250,000 kilometres on it when we tested it.
That makes it a good real-world example of what can happen when modifying an older, high-mileage Hemi.
Stock
267 wheel horsepower
304 lb-ft of torque
We then installed a K&N cold air intake and tested the car again.
K&N Cold Air Intake
276 wheel horsepower
298 lb-ft of torque
Difference:
+9 wheel horsepower
−6 lb-ft of peak torque
So while the intake produced approximately 3.4% more peak wheel horsepower, peak torque actually decreased slightly.
This is a good reminder that simply looking at one peak number doesn’t tell the entire story. When evaluating a dyno test, it’s also useful to look at the shape of the horsepower and torque curves and where gains or losses occur throughout the RPM range.
It’s also worth noting that this particular engine had more than 250,000 km on it. Not a fresh example by any means!
Test #3: Dodge Charger — Flowmaster vs. K&N
Our Charger test gave us an opportunity to do something even more interesting: compare two aftermarket intake systems on the same vehicle.
We tested the Charger in three configurations:
- Stock intake
- Flowmaster intake
- K&N intake
Stock Intake
276 wheel horsepower
325 lb-ft of torque
Flowmaster Intake
280 wheel horsepower
335 lb-ft of torque
Compared with stock:
+4 wheel horsepower
+10 lb-ft of torque
K&N Intake
287 wheel horsepower
334 lb-ft of torque
Compared with stock:
+11 wheel horsepower
+9 lb-ft of torque
In our test, both aftermarket intake systems improved peak horsepower over the stock intake.
However, the K&N produced the highest peak horsepower.
It made 7 more peak wheel horsepower than the Flowmaster intake during our testing.
Interestingly, peak torque was almost identical between the two aftermarket systems:
Flowmaster: 335 lb-ft
K&N: 334 lb-ft
WATCH FLOWMASTER VS K&N PART 1
WATCH FLOWMASTER VS K&N PART 2
WATCH FLOWMASTER VS K&N PART 3
Cold Air Intake Dyno Results Compared
| Vehicle | Stock HP | Intake HP | HP Gain | Stock Torque | Intake Torque | Torque Change |
|---|---|---|---|---|---|---|
| 2019 Ram 5.7 Hemi — K&N | 304 | 325 | +21 | 331 | 342 | +11 |
| Magnum RT 5.7 Hemi — K&N | 267 | 276 | +9 | 304 | 298 | −6 |
| Charger 5.7 Hemi — Flowmaster | 276 | 280 | +4 | 325 | 335 | +10 |
| Charger 5.7 Hemi — K&N | 276 | 287 | +11 | 325 | 334 | +9 |
So, Does a Cold Air Intake Actually Add Horsepower?
Based on these particular tests, yes—we measured increased peak wheel horsepower with every aftermarket intake configuration tested.
But the amount varied considerably.
The three K&N tests produced peak horsepower increases of:
Ram: +21 WHP
Magnum: +9 WHP
Charger: +11 WHP
That’s an average increase of approximately 13.7 wheel horsepower across these three K&N tests.
However, that shouldn’t be interpreted as a guarantee that installing a K&N intake will add 13.7 horsepower to every 5.7L Hemi.
These are different vehicles tested at different times and under different circumstances. Vehicle condition, mileage, existing modifications, engine management, temperature and other factors can influence dyno results.
What we can say is that all three 5.7L Hemi vehicles we tested showed an increase in peak wheel horsepower after installing the K&N intake.
Is a Cold Air Intake Worth It?
If you’re expecting a cold air intake to completely transform your vehicle, you’ll probably be disappointed.
But there are several reasons people install them:
- Potential horsepower improvement
- Improved induction sound
- Reusable filter on some systems
- Relatively simple installation
- A good supporting modification for additional performance upgrades
Our testing also demonstrates why we’d rather put a vehicle on the dyno than rely exclusively on advertised horsepower numbers.
Sometimes modifications work very well.
Sometimes the improvement is small.
And occasionally a modification doesn’t produce the result you expected.
The dyno tells us what actually happened on that particular vehicle.
Watch the Tests
We’ve documented these tests on the Dynomite Performance YouTube channel.
2019 Ram 5.7 Hemi Dyno Test
2019 Dodge Ram 5.7 Hemi Horsepower gains K&N intake – Edge Pulsar – Muffler Delete
High-Mileage Dodge Magnum K&N Dyno Test
K&N Cold Air Intake Horsepower Gains on a High Mileage Dodge Magnum RT Hemi
Dodge Charger Flowmaster vs. K&N Test
The Bottom Line
Our testing showed that cold air intakes can produce measurable horsepower gains, but the results varied significantly from vehicle to vehicle.
The largest K&N gain we measured in these three tests was 21 wheel horsepower on the 2019 Ram 5.7L Hemi.
The high-mileage Magnum gained 9 wheel horsepower, while the Charger gained 11 wheel horsepower with the K&N and 4 wheel horsepower with the Flowmaster.
That’s why we believe real-world testing matters.
Rather than asking whether a cold air intake claims to make horsepower, we’d rather bolt it onto the vehicle, strap the vehicle to the dyno and find out.
Dynomite Performance — Real Parts. Real Dyno Tests. Real Results.
