I have a 14" Edelbrock open element air cleaner on a 302. It's trapping heat, causing my carb to perculate. I ran without it before, and there was no perculation. I'm thinking of going to a smaller cleaner, maybe the Edelbrock small triangle style that won't be holding heat on the carb. Would there be a performance decrease by going to this type of cleaner?
[ QUOTE ] maybe the Edelbrock small triangle style that won't be holding heat on the carb. [/ QUOTE ] Don't waste your money or your ride with one of those. If the engine backfires, that element can become a wick. They have started many a fire on some cool cars. Buy a K&N topper if need be, but not that POS.
A 14" air cleaner allows more airflow that's spread over a larger area of filter element. I've heard that the bigger filters also lessen turbulence and provide a more laminar flow into the carb. None of this really comes into play until you reach higher RPM's. You probably won't notice any significant difference in performance by going to a smaller air cleaner.
[ QUOTE ] provide a more laminar flow into the carb [/ QUOTE ] Wouldn't this have more to do with air cleaner materials or baffles, or design, rather than size?
[ QUOTE ] Wouldn't this have more to do with air cleaner materials or baffles, or design, rather than size? [/ QUOTE ] I remember when Moroso used to promote their air cleaners with this claim. I think a lot of it (supposedly) had to do with the design of their lid coupled with the 14" size. They didn't make any claims for say, a 10" cleaner. Maybe the airflow needs more time to stabilize from the point it exits the filter to the point it enters the carb? I do know that with designs like K & N, the element material and shape is what its all about.
I would try the K&N topper. It will let air flow in the top and move heat away from the carb.I think...I would also think a smaller aircleaner would hold the heat in more. I've never heard of this problem before,,,, so what do I know.
The idea behind a bigger air cleaner is that you have more room for less turbulent air around your air horn or the carb opening for you guys that mill the horn off. I think in one book I read it said still air, kind of an oxy-***** if your engine is running. My Rochester book says that you want at least 2" of space between the top of the carb and the aircleaner top. I've read and or heard that other places also. Probably if you have to decide your best bet is try and stay tall. Those foam filters that Edelbrock and some of 'em sell don't do well on the flow charts, you're better off with a paper element than one of those. I try to stay above 10" dia and around 3" tall if I can, not always possible or desirable. Just depends on if you're after custom or performance I guess. Also how much room you got. If you're not racin' then whatever floats your boat.
i would not run one of those triangle filters on my lawn mower i have seen 2 cars burn cause of them. if you have a drop base air cleaner it will hold more hot air under it near the carb. you can try a flater base first before going to something smaller.
Large air filters serve as a plenum, this from the most talented engine man I know. He also built the bicycle that won the Tour de France
Like others have said, the large diameter air filters keep the noisy air at the edge of the filter. You want the air to be as directed (or "quiet") as possible as it heads toward and down the venturi. As a side note "Ram Air" is for jet engines, not cars. The noisy air created by turning your fancy chrome scoop towards the front of the car is actually making the car run worse. But then again, it looks cool. Cheapo white paper air filters, like the kind that are made for Stromberg 97 style carbs, stink. Get a K&N.
Perculation? By that do you mean the fuel is boiling in the float bowl? I have only seen this happen one time and it was a ford. It was a 390 galaxy with a water-heated spacer under the carb. I installed a non-heated spacer and that stopped the problem. It seams to me that an air cleaner ***embly could not hold much heat with a constant flow of air going through. The smaller the filter the faster it gets dirty. On my 302 I blocked the heat risers before I put on the intake, I feel I dont need any more heat in california.
The larger the filter, the more surface area there is to pull air from. Air restriction, will affect the mixture. I put one of those outerwears prefilters on my air filter one night and it wouldn't run, because it was too rich. I took it off and it ran fine. 500 cfm on a four banger can be a little picky. We've found that the cheap paper filters, flow better than the K & N's.
Thanks for the input guys.. The motor is a ford 302 in my 67 mustang. It's an off topic car, but there's so many people here that know so much, I really wanted to hear some opinions. It's a drop base, the edges of it are damn near my valve covers. I might be able to go another 1/2 taller, but that's about it unless I go with a hood scoop. The carb is a Edelbrock / carter 600cfm. It was fine until I got an aircleaner on it. Now when it gets above 95 degrees outside, and I park it, I can pull the cleaner and there's fuel dripping into the front barrels. This carb replaced a holley 600 that did the same thing. I'm going to get some thin plastic and aluminum spacers to put under the carb, but I was looking to do something about the aircleaner too. Man, it gets HOT... all the heat seems to radiate up through it. Again, thanks for the input!
The Jalopy Journal
