What You Actually Gain (Besides Engine Bay Clout)
✔ More Horsepower & Torque
AEM’s dyno charts show real gains on the 1.5T — typically +10 to +14 horsepower depending on conditions. That’s not “sticker horsepower,” that’s legit airflow improvement.
This Performance Air Intake System allows your engine to breathe more air compared to the restrictive factory air intake housing. It is designed, tuned and dyno-tested to produce more horsepower and torque.
✔ Better Turbo Sound
Nothing excessive — just the right amount of flutter, spool, and induction noise to remind you that you do, in fact, have a turbo. Congratulations, you’ll now roll windows down for no reason.
Air enters the system through an oversized AEM Dryflow synthetic washable air filter for outstanding air flow, filtration and performance. The air intake tube is constructed from mandrel-bent aluminum featuring a durable gunmetal gray powder coated finish.
✔ Improved Throttle Response
The factory airbox is basically a fancy plastic choke point. The AEM intake lets your engine breathe like it just quit smoking.
✔ Dryflow Filter = Zero Oil Drama
No oil-soaked filters ruining MAF sensors.
No headaches.
Just clean, efficient airflow.
A custom shaped heat shield with lid is included. The tapered cylinder shaped AEM Dryflow air filter is made from an oil-free, synthetic filter media that can be used for up to 100,000 miles before cleaning is needed (depending on driving conditions).
Why Civic 1.5T Owners Love This Intake
Because it fixes the one thing the 10th-gen Civic lacks: personality.
The 21-873C not only wakes up the car from a stop but also gives mid-range punch that makes passing easier and driving less “I bought this because gas was expensive.”
Plus, the powder-coated tube and heat shield clean up the engine bay, making it look like you actually care about maintenance (even if you’re overdue for an oil change—hey, I’m not judging).
Installation: Easy Enough for a Saturday Afternoon
No tuning required. No cutting. No soldering.
If you can operate a socket wrench without cursing (too much), you can install this intake.
Expect about:
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45–60 minutes installation
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A noticeable improvement immediately afterward
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A sudden urge to drive spiritedly “for science”
This Air Intake System is backed by AEM’s Lifetime Limited Warranty. Some AEM air intakes are not legal for sale or use in California and other states adopting California emission standards, while others are 50 state legal. View the vehicle applications to determine the legal status for each vehicle.
Final Verdict
The AEM 21-873C Cold Air Intake System is one of the best bolt-ons for the 2016–2021 Civic 1.5T platform. It adds power, sound, efficiency, and style — all without breaking the bank or your warranty.
If you’re looking for a proven, reliable, and vehicle-specific upgrade, this is the one to grab.
From the manufacturer
Erika N. –
I recently got a new car and wanted to upgrade the intake. From taking out the old and putting in the new, it really only took 10-15 minutes if that. The sound is beautiful! Nice turbo spool/flutter makes this already fun car, even MORE fun to drive. Definitely puts a smile on my face. Thank you for the great part.
Benjamin Reese-Taylor –
Pretty good little intake. Install was easy. Sheet metal didn’t fit properly at all though. Had to re bend all of it to fit but once it was in I was happy. Makes the sounds I want plus a cute little horsie gain!. Suggest getting a filter wrap for the filter. Over all I’m pleased with it.
Michelle Cintron –
Install was very straightforward. You’ll be able to hear the turbo spooling up better, and also get some sick bov sounds (with the HKS bov).
cec1999 –
I cant speak on performance because I havnt taken my car to a dino. I will say the noise it makes is great and does turbo flutter even in low rpms. I also think ive seen a slight increase in mpg but that could just be cope. Build quality all appears to be up to snuff and was easy enough to read instructions on where the pieces go and what to replace but the arrows could be clearer….The physical install was a nightmare with the frame not fitting unless you clip away some of the air director near the front. I spent hours just trying to get it in place before deciding to remove the plastic it was rubbing against. Id also like to see the rubber fitment pieces pre cut, kinda lame that you have to cut it yourself especially since it has metal in it that scissors won’t go throughI had to re-tap a thread because it came from the factory screwed up, which caused the corner to not sit in place very securely.Is it something id recommend? I mean… sure I get enjoyment out of it but it was definitely a pain in the ass and not as easy as people make it out to be online. If you watch any videos before hand you see they all skip ahead when installing the filter box bottom piece…Id also like to mention that the hardware bag it comes with has no labels for the screw, nuts or washers so you either have to measure them all or just guess because the instructions only have a small image that says where they should be but never actually tell you in the step by step instructions which I think is just lazy.
Indy –
Just installed it for my first mod on my car. Love the sound and how it looks. Would recommend.
JOSHUA –
The last two vehicles I’ve owned have gotten AEM vehicles, so I came back to a brand I trust once again. Installation was simple and this filter setup was a little different than past vehicles I have installed on. In the past the CAI’s have always gone down pretty low under the vehicle behind the drivers side fog light.I would not call the a true CAI, but with the included heat shields I’m hoping it will do its job and it is better than a SRI for sure.
Bill –
Update #1 DO NOT LISTEN TO AMAZON it say’s … aFe Power 59-20001 Takeda Turbo Inlet Tube for 2019-2020 Hyundai Veloster N doesn’t fit…. it absolutely fits!!!! It fits the STOCK Intake and it fits this AEM intake period. If you have a different aftermarket Intake it needs the bigger aFe Takeda Turbo Inlet 59-20002 which has a 4inch opening.WARNING……FULLY read the BAD instructions from beginning to the end before you make any cuts to the molding!!!! At the end of the install, it will have you cut more pieces. After I cut the first ones, I didn’t like how one of them looked so I was like I got extra I will cut a new one. Thankfully I waited until the end when I found out that the EXTRA molding is NEEDED!!!Very easy to install on my 22 Veloster N, took about 20 min with the cutting and install.The only con I have is the instructions are wrong in a few places, it puts things backwards: some washers and the way the logo is installed are completely wrong.
Derrick A –
This intake is truly worth every penny in my opinion, the highly enhanced turbo flutter and suction noise is exactly what the car needed to be even more perfect. AEM knocked it out of the park with this one to simply put it.
Faisal –
Precise measures
Very good quality fits the Veloster N perfectly
Sherif Youssef –
Genuine AEM product
Super quality and super timely delivery, box came a bit cracked but still no problemIf you have a Hyundai N vehicle I highly suggest it for the highest flutter soundPackage came a bit teared up but no issue