COWL INDUCTION - Team Camaro Tech
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post #1 of 13 (permalink) Old Oct 24th, 01, 07:19 AM Thread Starter
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Would the performance results be the same if the flap on the cowl was always wide open versus the flap opening as the accelerator is being depressed? Obviously mine is broken and wondering if I need to repair it.

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Andy
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post #2 of 13 (permalink) Old Oct 24th, 01, 07:51 AM
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The flap doesn't open as the accelerator is depressed. It opens fully when the accelerator is at WOT. It's either open or it's not, no in between. I know some of the guys on this site have taken the flapper out just because they have a habit of getting "hung up" either open or closed.

As far as performance goes, I don't know if you would realize any gain or loss. Maybe someone here has done some testing on this.
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post #3 of 13 (permalink) Old Oct 24th, 01, 03:09 PM
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Open is better unless you are driving in a blizzard.
David

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post #4 of 13 (permalink) Old Oct 24th, 01, 04:20 PM
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Mine is fixed open all the time, looks neater than not havng one. I've driven alot in bad snow and rain, and can even see chunks of snow going in at WOT, but never had any problems. I have small holes in the pan for water drainage.

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post #5 of 13 (permalink) Old Oct 24th, 01, 04:52 PM
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Over at chevelles a little while ago there was a post on ram air type setups (either under the bumper or in the grill). The consensus seemed to be that the ram air produced no noticeable gains in ET. But I don't think cowl induction was brought up. My question is does cowl induction actually work? I know it looks neat but does anyone have before & after time slips?

Dan
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post #6 of 13 (permalink) Old Oct 25th, 01, 02:57 AM
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Cowl induction works!! GM did all the math for you back in the sixties.

Obviously, it's a lot better to have 60-90 degree air entering the carb. from a sealed plenum to the outside than it is to have the engine breathing the heated, 150-250 degree air from under the hood! There's also a great air pressure point at the base of the windshield that cowl induction exploits.

Cold air makes for a more dense charge in the cylinder. It's just basic physics.

By the way, it's OK to have the flap open all the time in a performance, warm weather car. GM put the flap in for several reasons.

1) To keep the engine breathing preheated air when it is cold. This promotes fast warm ups and better cold performance.

2) To keep the engine noise down at cruise speeds. The government inspectors have always hated noisy cars!!

3) Ya gotta admit that the moving cowl induction flap is a pretty cool gadget!! Everyone likes cool gadgets!!

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post #7 of 13 (permalink) Old Oct 25th, 01, 04:40 AM
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I actually read a review from the 60's and the magazine thought it was mostly a gimmick back then. I know the theory behind wanting cool, high pressure air entering the carb. But has anyone tried a before and after cowl induction on their car? Or is it just something that people assume works?

Dan
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post #8 of 13 (permalink) Old Oct 25th, 01, 04:43 AM
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just to throw in my 2 cents, I opened up the shaker on my t/a and i think it would be a good idea to put a mesh over the opening if your going to be dealing with tuff weather and leaves. just a suggestion
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post #9 of 13 (permalink) Old Oct 25th, 01, 11:46 AM
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All else being equal, every 10-degree drop in intake air temperature can gain about a 1% power increase; ram-air doesn't do much more than look good, as the engine needs a whole lot more air at wide-open throttle than you can get through a little hole in the hood.

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post #10 of 13 (permalink) Old Oct 25th, 01, 11:51 AM
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but john, you must remember that it sounds cool
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post #11 of 13 (permalink) Old Oct 25th, 01, 07:05 PM
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It also looks cool to see the air filter in there while you're driving. Is shakes around with the engine vibrations, and you always have a clean filter or then it doesn't look so cool.
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post #12 of 13 (permalink) Old Oct 25th, 01, 07:39 PM
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It seems like the consensus is that it looks cool and works in theory. Does anyone have definitive info on cowl induction performance improvements?

Thanks,
Dan
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post #13 of 13 (permalink) Old Oct 26th, 01, 02:44 AM
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A few months ago, Car Craft did a comparison at the drags. It made a difference even without being sealed.

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