Im skeptical....  My wrench SWEARS my 81 will pick up some noticable juice if I switch the air filter.  The car is in perfect tune w/a Edelbrock intake and a custom mufflex exhaust.  Any truth or wivestale?  Opinions?  THANKS!

The K&N is a superior filter, but it's a very individual thing how much of an increase (or any increase at all) you'll notice. It's always a good thing to increase the efficiency of airflow.

I have K&N air filters in all my cars, including my '78 L82 and '69 427/435. Do I notice an improvement...not by the seat of the pants dyno, but gas mileage did increase slightly...not much but measurable.

Figure it this way...just to pick a number at random say you'll see a 5% increase in fuel efficiency. A car that gets less than 10 mpg like my 427 will notice a very small increase at that 5% level. With a car like my '78 that gets 15-17 mpg the 5% difference will be more noticeable. Cars that get even better mpg numbers will see even more dramatic increases as long as the 5% increase stays constant, but we also know it doesn't in every car since there are simply so many variables.

In my '02 Avanti with an LS1 engine I instaled a K&N air filter and yes I did get an increase in power through my "seat of the pants dyno", but would the difference show up on a real dyno...who knows? I did end up changing the Mass Air Flow sensor on the car due to the increase in airflow causing "check engine" lights. A Granatelli MAF tuned for cold air flow took care of the situation as well as a real boost in performance.

K&N filters aren't cheap, but I believe they're worth the money.

I had a 1992 Chevy truck, 350. It felt like more power and did get better mileage. My 1994 Chevy motorhome,350, helped it a little, made more carb noise. I did get more mileage from our 2001 Monte SS, it pulls 31 to 35 mpg on trips. I think they work good, but it takes awhile to recoup your money.

Denny

I've used K & N in all my cars for years. Noticed slight increase in mileage & on the 68 BB I use the K & N Top filter which does allow more air ...don't have much room in there & with a L88 hood  it does get the cooler air. I have a 2003 Tahoe & I installed the K & N intake performance kit & I did notice a difference in power & mileage...gained about 10% . Plus if you keep a car you only have to buy an air filter once.

Alan

 

I also prefer the use of K&N filters.  They are high quality and personally I have felt a difference when I changed out the stock to a K&N.  Not so much with the old vette engine I had as compared to when I put the K&N FIPK onto my F-150.  I noticed a big difference there.  And as gmurray said, its nice to be able to take it out and easily clean it when you have to.  Its worth the extra money!

I agree, I put one on my 79 L82 and noticed a difference.