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Flat base air cleaner vs drop base air cleaner

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  • Flat base air cleaner vs drop base air cleaner

    Here goes, I wasn't sure where to put this one so it's going in this section. I've been thinking for quite some time now about trying a flat base cleaner on my car instead of a drop base based on a bunch of reading I've done, and I just like to try new things anyways. Anyhow, with my cowl scoop I had plenty of room to do it so about a month ago I did. I only changed the base, kept the same element and lid. I've been using a 14 x 4 K&N element with a domed lid, btw. The first thing I noticed after the swap was the car seemed a bit more responsive. After a couple of days I noticed it seemed to be getting better highway mileage. Well a few of us cruised down to a car show in a town about 120 miles away last Sunday. Big surprise for me. Last year when we did that, it took me about 3/8 of a tank each way if I took it real easy. This time it was only 1/4 tank each way - huge improvement! Has anybody else here played with bases, and if so, what were your results? The only down side for me is I wanted to put on one of my Formula hoods sooner or later and if I keep this air cleaner set up, I just can't do that. The thing sits over 3" through the hood now, lol.
    If you still think you can turn the steering wheel - you're not going fast enough

    What Would Bubba Do?

  • #2
    Any pix of your set up?
    - Christopher - They call me Devil Beard

    Hoarder of various 2nd gen Trans Ams and Firebirds/ 73-77

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    • #3
      Sorry Chris, can't do pics at the moment, camera's hooped.
      If you still think you can turn the steering wheel - you're not going fast enough

      What Would Bubba Do?

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      • #4
        Using a Torker 2 with a 1" spacer and an 850 Quick Fuel though, if that's any help.
        If you still think you can turn the steering wheel - you're not going fast enough

        What Would Bubba Do?

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        • #5
          Well, I don't like cowl hoods on a Firebird enough that I'll never do this, no matter how beneficial it is, but it does prove my thoery on the drop base air cleaners. Probably one of the biggest limitations of having a shaker. I've always suspected that I was limiting airflow with my custom drop base design, so that I could fit an RPM/Crosswind intake on, but choices are not really there. I got a junk shaker base from DB that I'm gonna experiment with. Maybe do some type of ram-air design with dual feed horns to the grills. Not sure that will do much either. Being that I'm really picky about a clean engine compartment, I doubt it will go over well for me. There are just some things I'll never do to a TA. Use a cowl hood/snorkel/hood scoop, and attach a shaker to the hood. I know there's gotta be a way to get better airflow to the carb without sacrificing the shaker, but I have too many projects going to spend a lot of time on it, like I need to.
          -Mike

          This is not something you buy. It's Something you Build!

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          • #6
            Yeah Mike, I couldn't see you ever using any type of scoop on your car, it just looks too good the way it is. Besides, it is a T/A. Mine was a base model car, and with me it's more about function, so putting an ugly cowl scoop on it wasn't as big of a deal to me. Sometimes the look of the scoop really annoys me and I'd even put my stock 455 back in the car just to use my stock hood or a Formula hood. Who knows, may do that yet, lol. Maybe I could put my RPM intake on with no spacer and a shorter filter element and fit everything inside the hood. I'd only be down to around 500 horse doing that. May try that someday too. The thought of going back down to 10 mpg or less pisses me off a bunch too though, lol.
            If you still think you can turn the steering wheel - you're not going fast enough

            What Would Bubba Do?

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            • #7
              Flat base air cleaner vs drop base air cleaner

              My theory would be less air = less fuel burned. I can't see how there would be a performance gain. If the throttle was more responsive to the flat base I'd say the tune you have, along with the other elements involved liked it better.

              1972 LeMans W/Endura Front End & 461 CID

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              • #8
                Originally posted by GratefulDiver View Post
                My theory would be less air = less fuel burned. I can't see how there would be a performance gain. If the throttle was more responsive to the flat base I'd say the tune you have, along with the other elements involved liked it better.
                You would think so, but from what I remember there's more to it than that. Things like turbulence, booster buffeting, etc all come into play. My tune probably has something to do with it also, considering the engine was tuned and set up on the dyno, and wasn't using any air cleaner for that. Damn, now I'm gonna have to go back and find this stuff so I can figure out what the hell the over all picture is. lol.
                If you still think you can turn the steering wheel - you're not going fast enough

                What Would Bubba Do?

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                • #9
                  Quick article from Car Crap magazine.

                  http://www.carcraft.com/techarticles...er_comparison/
                  I'm the Rick in prick.

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                  • #10
                    Your carb doesn't stop pumping gas if the airflow is restricted. Tuning makes for better mixture of the two, but restricting one or the other means more inefficiency in the burn. This is how fuel is wasted. Opening up that airflow, and give the carb tuning what it's asking for, makes for a more efficient use of the fuel it's getting. Tuning is most of it, but not too many people tune with the filters in place. Especially on a T/A with the drop base in the way.

                    Also, opening up the shaker on a TA does nothing for airflow. If you look at one assembled, you'll see that the lid of the breather fills up the hole. Older style shakers may have a bit more gap, but I doubt it'enoughng to make any difference. I use a filtered lid, but I can't say it helps anything. In fact, I've read just the opposite. It's a necessity for my car, since it's the only air that gets to my carb. This is why I'm looking for a better alternative.
                    -Mike

                    This is not something you buy. It's Something you Build!

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                    • #11
                      Airflow into the carb does have some effect on the fuel since the venturi effect pulls more or less fuel through the boosters. I was searching for an article I read some years ago that actually tested various drop bases and stock flat bases. They also did a test with the breather lids, like the K&N I think Mike is talking about. I remember at least on of the drop bases being shaped to increase and straighten flow into the carb, much like Tweety was refering to with buffeting, etc. 3 or 4 pages in the google search netted me nothing, and frankly, my short attention span kicked in. LOL

                      As for your open shaker Mike, the claimed benefit was supposed to be that the open shaker was allowing cooler denser air in as opposed to hot underhood air. Even the functional factory shakers were said to benefit from temperature, not quantity of airflow.
                      I'm the Rick in prick.

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                      • #12
                        Tweety, you may experiment with different bases as well as booster designs if they are available for the carb you're using. Again, I have read an artical or two comparing drop leg versus straight leg, different diameters, etc, having an effect on the air fuel mix. No personal experience, but a pretty informative artical at the time. Probably Hot Rod or Car Crap again as those were some of the only mags I typically got regularly besides HPP, and they never went into such depth with their tech articles. Come to think of it, it may have been in Drag Racer or Drag magazine as I sometimes pick up copies of those if they have someinteresting tech article.
                        I'm the Rick in prick.

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                        • #13
                          You're not pulling cooler air in if you're blocking it with the lid. The lid covers the entire shaker opening. You might cool the lid, but I don't see how any benefit comes from it.

                          yours truly,
                          The Lord of Hardcore
                          -Mike

                          This is not something you buy. It's Something you Build!

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                          • #14
                            Does your shaker lid attach to the base? Mine is a smaller diameter and leaves at least a 1" gap between the edge of the lid and the base. The OD of the lid is the same size as the OD of the element inside of it.
                            I'm the Rick in prick.

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                            • #15
                              Like this one. When the shaker top/scoop is attached, it leaves that air gap all the way around so that if the shaker is open, it can enter the cleaner base around the lid.
                              Attached Files
                              I'm the Rick in prick.

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