I put the K&N 77 Series kit on my 2011 F150 5.0. Its great at a little higher RPM, REALLY gets loud on full throttle plus my duals, but..............
Lower RPM and initial takeoff have lost a little in my impression. When I am cruising at a sustained speed now it also seems like it bogs down more before it downshifts too and I think this is where I lost a little on MPG also.
Has anyone else had positive or negative feedback on the 77 Series from K&N?

 

Waste of money. You're seeing all the common issues - loss of power down low, no increase in MPG. Other fun things that await you are damage to the MAF sensor due to the oil (over-oiling) and the pass-through of fine grained particulates that a standard paper filter would stop.

 

I wonder how the Roush conversion compares?

 

I think it's been pretty well agreed that unless you do serious work on the motor (supercharger, etc.) the stock air filter is just fine.

 

did you take the negative off the battery when you installed it?

 

I have an update on this. I went on K&N website and sent a quick note to customer service about my issues. They immediately responded back and though a dialog of multiple emails, conversations they asked my to try and double check a few things which I did. All ok. To my amazement they called and asked me what can they do to make it right and if the cant, they would refund my purchase price, even though I purchased through Summit. Long story short they are sending me a different intake tube to try form one of their other CAI kits and all the hardware to make sure it is a direct fit. I'm to install, run it and give them feedback.
I have rarely had such nice, polite and helpful customer service as I have had with K&N. We will see what happens when my new parts come and what the outcome is.

 

Good to know that they assisted you well regarding your concerns. Keep us posted.

 

My first 2 F-150's I had, I put the same K&N FIPK 2 on them along with one in and 2 out of muffler dual exhaust. Those trucks didn't feel any faster or get better mpg's, but the intake sound was sweet. IMO, a forced air intake works better with not just exhaust, but a good PCM tune. It works best with head and cam work.

 

How did your new tube, they sent you work out? I'm wanting to get a K&N intake aswell.

 

If you look at their dyno charts, that's also where the extra airflow is. Depending on the vehicle, that can be outside the peak HP range of the vehicle. Gas burners do like their higher RPMs, but sometimes you can go a little too high.

I know with the 6.0, most a/m intakes flowed better at or above 3500 rpm (K&N was also the worst in some areas as well (including filtration)). Problem is peak HP on a stock 6.0 is 3300 rpms. A little too high, powerband is already on the decline then.

Now, yes that is a different vehicle, but the key thing to look for is the same. Not really if it flows more, but when does it flow more.

Stock really has gotten better (if not plain better, I know my 6.0 is moderately modified and I still use the stock air filter), so it's not as simple as it used to be when you already knew you had to change this, that or the other to get better components.


If the tube that they send compresses the air flow, that might help it do better lower in the powerband. It would be interesting to see what your results were on that.
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Ok, I got the plastic tube and have it installed. I now have about 1200 miles on the new tube and am still not that impressed.
It's a stepped tube vs the consistent diameter on the chrome tube. It did correct a very small bit of the lag on low RPM and initial acceleration but not enough to really make a difference.
K&N has offered that if I am still not satisfied they would refund my money but I figure it's my mistake for not doing my research correctly.
As stated at high RPM it flows and works pretty good, but over all in the RPM range we all use most often it just does not live up to the hype and costs me fuel economy.
Long story short, it came off and I sold it to my buddy who just loved the sound and could not give a rats *** about economy.
Lesson learned.

 

I just removed my Airaid drop-in filter on my 2011 f150 EB. It turns out it was costing me fuel economy also and it was sluggish in the lower rpm. Reinstalled a brand new motorcraft filter and my mpg's are back up. Plus I have more faith in the motorcraft keeping my engine clean.