AEM Cold Air Intake ( Part Number:AEM 21-678C)

AEM Cold Air Intake

MODEL # AEM 21-678C
Manufacturer Part # 21-678C


MSRP: $453.49

In stock! Ships same day
Qualifies for free shipping!

Buy as a package deal and save:
RallySport Direct Evo X Project Car POWER Kit ( Part Number:RSD EVOXPC)
RallySport Direct Evo X Project Car POWER Kit
As low as $7,372.31
View Product
AEM Intake Systems are designed to increase horsepower and torque gains as well as better engine sound when used as a replacement for the factory airbox and air filter. AEM intake systems are designed, tuned, and dyno-tested for vehicle specific applications.

These kits include an oversized AEM Dryflow synthetic washable air filter for optimum air flow, filtration, and performance while allowing easy oil-free cleaning. AEM intake systems use mandrel-bent aluminum intake tubes, and high quality hardware designed to reduce restriction and reduce intake temperature.
| | | | |

Brand: AEM
Carb Exempt: Yes
Carb E.O. Number: D-670-21
Filter Color: Red
Filter Element Type: Dry
Filter Material: Cotton
Filter Reusable: Yes
Includes Airbox: Yes
Piping Color: Black
Piping Material: Aluminum
Tuning Required: No

Mfgr. Warranty: Limited Lifetime Warranty
Condition: New Product
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.


Verified Purchase

AEM Cold Air Intake Evo X
tashlhautara94556 1 year ago
Install was a little difficult, the rubber weather stripping on the air box was a little hard to put on and it overlaps at the tips. Then the supplied rubber hoses were a little long and were causing a crimp in the hose due to tight bends. need some trimming. Next problem I had was the metal arm that comes off the aluminum intake tube does not line up to ANYTHING. Worked with it for a good 15 minutes trying to fit the intake pipes different directions. And lastly, my stock blow off valve rubs the stock strut bar. Overall I would reconsider buying this intake. And I've never had a bad experience with AEM. But as always, rallysport direct is awesome on their customer service and shipping.
Verified Purchase

jylese 5 years ago
I bought several items for my car to include this and the COBB Inter Cooler Hard Pipes... They DO NOT line up together. The Turbo inlet hose was to long and put my BOV into my Strut Tower Bar... I trimmed an inch off bottom to get that to line up right. Then the brace on the Cobb Hard pipes still won't line up without creasing the turbo inlet hose.
Verified Purchase

AEM Intake
dee 5 years ago
Bought this mainly for the concealed filter & CARB sticker.Install difficulty was average for a person who can turn wrenches once in a while. The instruction manual could use some arrows to point out exactly what they are referring to but overall, I am really satisfied with how this performs. I can hear the turbo spool up & the BOV for the first time! Thanks rallysportdirect for the super fast shipping!
Verified Purchase

Aem CAI Evo X
salasbass1302758 6 years ago
All and all a tight package. The install was more involved than most. Hate with a passion the rubber grommet material used to isolate the air box/intake module. It's not flexable and seats very poorly. I'm over it. Seat of the pant's test feels like maybe 5hp manfacture claimes 17hp.Quiet system=nice..! Two thumbs up

  • Q: Require a Tune?   Logan_ry 1 year ago


    Does this AEM Cold AIr Intake require a tune for 2008 Evo X MR?

    • A: We strongly recommend a tune anytime you are changing the intake for best performance and reliability, but AEM states this does not require a tune.

      Nick S. 1 year ago
Mitsubishi Lancer
Evolution GSR 2008, 2010, 2011, 2012, 2013, 2014, 2015Evolution MR 2008, 2010, 2011, 2012, 2013, 2014, 2015Evolution MR Touring 2010