My experience with K&N CAI

I bought and installed the K&N CAI system

$350 63-9039 K&N Cold Air Intake System: High-Flow Air Filter, Increase Performance & Towing: Compatible with 2016-2023 TOYOTA Tacoma, 63-9039

63-9039 a couple weeks ago. I have put 1000+ miles on and have some observations.

First, it is louder than expected at 3/4 throttle or more. A lot of people say they are loud at given RPMs, but it has a lot more to do with throttle position than RPMs. It will make noise even at 1800RPM if you are stepping on it. 3500-4k RPM at heavy throttle will resonate a bit. However I love it and have no complaints about this.

Mileage ultimately has improved but has been hard to track. I say this because I think if you could compare before and after while maintaining the exact same RPMs, I don't think it has necessarily improved. But that goes into my next point, which is that it is holding gears infinitely better. If the road is flat, I can stay in 6th even down to 50mph (around 1100-1200 RPM). It would never do that before (on 33s). Of course once you hit a hill it wants to downshift. But on slight inclines at speed, it usually stays 1 gear lower than it used to.

I also noticed right away it does not hesitate from a dig anymore, even with ECT off. Along with this it also shifts into the lower gear right away after cresting a hill for example. It used to hold onto the higher gear for a long time even after descending. I will say it seemed to take an hour or two before it figured this out (I reset the ECU by pulling the battery cable as recommended by K&N). My weirdest observation with this whole thing is that if I ever feel like it is in the wrong gear for too long with cruise control on, I can actually step on the throttle and it will upshift to what I believe is the right gear. I don't know if it would do this before or not because I never tried it but I don't think it did.

I drove 500+ interstate miles twice within a month, once with the intake and once without. Average speed both times was 70MPH with 95% cruise control. Observed fuel economy was 15mpg before (on the trip computer, hand calculated 15.7) After the intake it was about 18 (18.8 hand calculated). The only difference is that on the trip with the stock intake, I did have about 200lbs in the bed.

I plan on doing a trip with more 80MPH speed limits soon and am interested to see how it does. I am initially thinking the difference will not be as noticeable because once I hit 80+, it still wants to stay in 4th or 5th gear. The last time I did this with the stock intake, I was running about 14MPG and it stayed in 4th gear 90-95% of the time.

The tank I am running right now has half highway (65MPH) and half city. It was reading 17.5 (not great for the lower speed highways, but I went from 100 ft elevation to 4000 ft.) Once I started driving city, it has surprisingly gone up to 17.9. Likely well over 18 once I hand calculate it because the computer seems to read low.

I do believe between this and 4.88 gearing I will achieve 20+ MPG again like when it was stock.

 

I'm not completely against intakes. In fact, I had the TRD one in my 2009 but it was paired with a MAF calibrator. For the most part, throttle response is improved due to a less restrictive design. Does it give more mpgs or power? I would say yes but very slight gain to justify price and mostly at the upper rpm range.