Do you guys run high flow air filters like K&N? Under what circumstances are they called for, and what differences has it made? Thank you.

I do. I emailed K&N tech to ensure that the filter I'm using will be sufficient. I didn't notice any difference over the paper element I was using. If the filter you're using now does not choke the engine, you probably will not notice anything. On the other hand, if your current filter is a restriction then you should notice something at the higher revs. I mostly like that they're reusable.


Lawrenceville, GA

I put my original T-bird air cleaner in the attic for "the next owner".....and put a low restriction oval outfit on there, with a K&N element. First problem was making sure the engine stood up straight under the hood scoop. The steady rests can move it to the right spot.

And then I got an el-cheapo (used) small oval air cleaner off ebay - polished it up and fitted it with a K&N element.

I personally like the noise of the "unsilenced" air cleaner when the engine gets the message to go......And then I ran some tests to see about how hot the air was under the hood. Horrible temp rise - it eats nothing but waste heat from the radiator. So then....

then I built this air pan and sealed the sucker (Demon Jr. 525) to the hood. It lowers the inlet air temp by a major amount.......but it didn't like taking all its air through the slots in scoop grille and whistled like crazy. So I got an el-cheapo hood grille off ebay - and removed all of the intermediate bars with a Dremel - and sent the result to the plater (another $50). You could then feel this change in the seat of your pants. I believe the old rule is 1% horsepower increase per 10° of inlet air temp drop - but if thats true I got about 4%

I don't have a close up - but it looks fine for a streeter - and shakes nicely when you are out front "watching through the window" - like buzzing it for kids and appreciative old guys at crosswalks.

I've got the air pan rigged to come off with the air cleaner - and will be swapping to another "show" version (no air pan) when it needs it.

 
 Steve Metzger       Tucson, Arizona

I am currently experimenting with various K&N sizes to fit an original 55 Bird aircleaner lower section (with velocity stack fitting), mated with a modified aftermarket (paper type) stainless top. K&N listings offer a very large selection of size/construction, and I am hoping to find just the right one with maximum area/flow that will work, and still fit under the hood. I'll try to remember to post specs/part # if finally successful.

6 VOLTS/POS. GRD. NW INDIANA

My current paper filter has a 14" diameter and 2.125" height. I think I would like to switch to something more breatheable, and also reusable. Wow Steve, you've done some interesting research. Makes for informative reading/viewing. I have the little Bird scoop grille with a Demon carb. Air cleaner has a stock '56 lower section with an aftermarket stainless top for the '57 Bird which has a lower profile than the more bulbous original on the '56. Anyway I am thinking about this K&N:

http://www.knfilters.com/search/product.aspx?Prod=E-3740

Isn't that a song??



When I originally installed the K&N, I went from a 10 x 4 paper element to a 9 x 2 K&N and noticed no difference. That doesn't necessarily mean that the K&N is that much more efficient. I think the 10 x 4 was simply more than was necessary. Just FYI, K&N said that their 9 x 2 filter was good for about 650cfm.

A 10 x 4 round filter is about 125 square inches. A 14 x 2.125 is about 93 square inches. With the paper element and subsequently the K&N the motor could easily reach 6000rpm and probably higher - I never tried it. The 9 x 2 is about 56 square inches.

Anyway, the point is that I think that 14" filter should be sufficient and if there is any restriction, it is probably the housing rather than the filter.


Lawrenceville, GA

Charlie - You ought to be figuring out a "cold air package" for your outfit - there's lots of room under a truck hood compared with our little birds. I think that hot air ingestion thing is really a power reducer.....

 
 Steve Metzger       Tucson, Arizona

I have thought about it. I can't really figure out how I want to do it. I don't want it to be obvious with the hood closed so a scoop is out of the question. I have thought about adding some vents on the back sides of the hood. The idea there is that the vacuum created by the air flowing past when the truck is in motion will draw the hot air out. The hood really doesn't seal all that well so I don't know if it will actually have an effect.

I can pull from the wheel wells, the grill, or devise a stealthy hood scoop. I don't really like the wheel wells or the grill because it means tubing will be laying over something which will need to be supported somehow and it will get in the way for some maintenance operations.

There is also a gap between the hood and radiator support when the hood is shut. If I was to open that area up and kinda mold scoops into the hood, at least it wouldn't stand out like a scoop placed deliberately on top of the hood. Then the duct can be supported by the hood and it can seal like yours. When viewed from the side, no one will ever know.

We'll see. I'm trying not to put too much on my plate this year so I can make it to Columbus.


Lawrenceville, GA

I'm running a 13 x2 inch K&N in my 57 tbird air filter system and it's close but it fits under the hood of the bird. Same setup under the 56 Sunliner but 3 1/2 inches tall ( alot more hood clearance ).

-Gary Burnette-

Some air pressure measurements could be instructive. I wonder if sealing the carb to the hood also produces a supercharging effect at speed?

6 VOLTS/POS. GRD. NW INDIANA