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Do air dams really help to cool?

Discussion in 'The Garage' started by Can Can, Sep 19, 2006.

  1. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    I was reading a GM troubleshooting flow chart today that insinuated that running without an air dam on the bottom of the front bumper could be a factor in making your engine run a little warm.

    Is there any validity to this claim? Has anyone removed their air dam and noticed higher operating temps?:confused:
     
  2. Cricket

    Cricket 3/4 ton status

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  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Pretty interesting...and quite logical once explained.

    Rene
     
  4. sledheadak

    sledheadak 1/2 ton status GMOTM Winner

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    they design the airflow to the radiator and other coolers with the airdam in place.changing that will change the airflow.look under a newer rig and you will see lots of rubber and plastic panels that direct the air into the coolers.
     
  5. Ben B.

    Ben B. 1/2 ton status

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    Air dams are absolute junk. My old man had a '96 Dakota 3.9 and as soon as you went through a puddle the airdam would suck it all up and the thing wouldn't run for crap.
     
  6. cbbr

    cbbr 1 ton status GMOTM Winner

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    I have no idea about the technical info, but it was one of the first things to go on mine and I have had no problem at all.
     
  7. jarheadk5

    jarheadk5 1/2 ton status

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    Some applications are more dependent on the airdam than others...

    My '86 Trans Am ran hot at highway speed when I first bought it, but as soon as I slowed down below 30mph or so, it would cool off. I flushed the cooling system, had the radiator boiled & rodded, replaced the thermostat, all the usual stuff... still did it. Happened to run into a high-school acquaintance one day that summer, who'd gone to Auto Shop in tech school and had scored a job at a local dealer; I mentioned the overheating to him while he was admiring the car, and he immediately went to the front end & looked underneath. "Your airdam's missing. Either you or the previous owner drove up to a curb or parking block too close and broke it off. Get a new one and your problem will be solved." Sure enough, there was an obviously-broken chunk of plastic on the unibody "crossmember" below the radiator.

    After a phone call to the dealer to find out the cost of a new airdam (about $100 IIRC), I found a piece of stiff plastic at home that I could cut-down to proper size, and put that in place of the old broken one. A half-hour blast at 80+ down the interstate with the temp gauge anchored in the normal position showed the fix was a success.

    It was later explained to me that the airdam creates a high-pressure area in front of the radiator, and a low-pressure area behind the radiator, which basically pulls air through it. If you think about what an '84-'88 T/A looks like, there's NO openings in the nose for radiator cooling - it's totally dependent on the airdam's management of the air under the car. Above 30mph or so, the fan(s) can't pull enough air through the radiator to combat the backflow (mentioned in the Morgan article), and it overheats.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    The simple fact of the matter is, they wouldn't be there if GM knew they didn't work.

    They (cars, trucks, etc) didn't come off the line with a heating problem, therefore, the cooling system worked, and that's part of it. Start messing with the stock setup, expect to have problems GM didn't anticipate.
     
  9. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    Another benefit of air dams (even the short one they put on some K5s), and this should appeal to a lot of the folks around here that buy an old, full-size 4x4 and then howl like stuck pigs about their rolling dinosaur's semi-ravenous fuel appetite. I mean, low mpg in a low-geared, big-tired, heavy, boxy, carbureted, old truck - who'd have expected that? :doah:

    They reduce under-vehicle airflow and thus aero drag, which is considerable with all the hardware hanging down under these big boys, and as a result, they make a small improvment in fuel economy at speed. They also cause a small reduction in wind roar and cabin noise at speed. Unless one needs that little bit of extra approach angle, it's an all-around winner.:waytogo:
     
  10. 89K5guy

    89K5guy 1/2 ton status

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    I sure see alot of K5s without the airdam.In fact when I bought mine the airdam was already gone.I have been to all my local junkyards and no luck;just hate to pay big$$ for a new one.
     
  11. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Funny you should ask this. I thought they were just there to aid air flow and decrease fuel consumption, but I took mine off when I lifted my '91 recently and my engine temps are up ever so slightly. I put this down to my new motor even though I've re-programmed the ecu and have it running really well.
    It's not up dramatically but it is noticeable. I can see the theory behind it now I think about it. Not sure it would make a lot of difference on a lifted rig though?
     
  12. tx_sub

    tx_sub 1/2 ton status

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    Correct me if I'm wrong, but aren't the air dams on GM trucks and suv's optional equipment? I bet GM didn't worry much about fuel mileage on trucks when they offered the air dam as part of a trim package, it was something else they could charge you for to make your Silverado a bit more different than the Custom trim levels.
     
  13. 4xcrazy

    4xcrazy 3/4 ton status

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    I think that little read where it says to install a piece below the radiator meant between the actual radiator and crossmember frame, not below the bumper..

    And from what i have always understood of these underbumper air dams, they were, as mentioned already, meant to help with air deflection to lower the under carriage turbulance for slightly improved fuel mileage.

    I don't think they had them "back in the day" but most newer models usually came with them when the fuel economy era started up, my 2wd 1/2 ton has one too.

    But the one thing you have to look at, when you raise the truck from stock height, you are really defeating it's purpose anyways, so i don't think it matters if it's on there or not,,,,i kept mine on just because i personally like the look of it:p:



    RACECARS,,,use this same technology, lower the front air dam, to keep the air from going under the vehicle for more speed, less drag, wich also helps with fuel mileage (slightly):laugh:

    But the ones like mentioned on the Firebird, Camaro and other sedans, ware used to help create a vacuum in the engine compartment to help the airflow through the radiator, I had a IROC Camaro with a overheating problem, it is a neccessary item.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    AFAIK they weren't optional. Never seen an RPO for them.

    Honestly, they so commonly got hit and broken, I'm sure the majority of them have just been removed.

    You still help create a "wall" in front of the vehicle no matter the height, that wall means the air has to go up or down, you are still increasing the amount of air that HAS to go through the radiator.
     
  15. Brian_D

    Brian_D 1/2 ton status

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    im guessing trimming it would mess up the air flow..? i just dont like how it looks, but if it really makes that much of a difference i will leave it be
     
  16. Irish1941

    Irish1941 1/2 ton status

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    Took mine off and temps are the same.
    110 thru the desert @ 70 or 95 degrees in town, never changes.
    On a Blazer or Sub, you're pushing a brick thru the wind.
    As far as I can tell, the air dam cut down on air under the truck. Pushing it to the side rather than under under it. Under would create drag off diffs etc and and goodbye to that EPA mileage rating. Camaros, 'birds and Corvettes all had deflectors pushing into the rad as where on a truck, it just goes around. Look at the design of it. Nothing deflecting up into the engine bay.
    When we ran land speed cars, we pushed air around rather than under. Under made drag but also lift. Nothing like doing buck 40 and rear wants to say hello to the front end.
    Belly pans helped a lot but all the suspension, axles etc was inside the pan.
    So no, I don't think it makes a difference.
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    I wouldn't waste time trimming it. Either leave it or remove it completely.

    I ran around without it for quite some time, never noticed a difference either in MPG or engine temp. The only time it's going to be effective is the freeway, and NORMAL freeway driving does not force the engine to work hard. Towing is a different story.

    BUT as with anything, if the cooling system is marginal for your rig, you MIGHT have problems once removed. There are so many alternatives/cooling system modifications we can do (huge radiators, big fans, better water pumps, etc) that the air dam can easily be removed, as long as the cooling system is more than adequate for the truck.

    I suspect a lifted rig would see even less of a difference, since the distance to the ground is greater, there is no way you are generating much airflow through the radiator since the air can just as easily flow under the rig. Along with the radiator, the tapered factory fan shroud is going to increase pressure in front of the radiator at speed, which further limits flow through the radiator. But again, that's theory. In reality these trucks have a massive radiator, massive frontal area, and massive cutouts for airflow over the radiator.
     
  18. Blue85

    Blue85 Troll Premium Member

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    It's clearly a highly effective and perfectly optimized piece. I removed mine to increase the air flow under the vehicle and thereby generate lift. Once I reach highway speed, the K5 only weighs about 3lbs, giving me over 100MPG and almost no tire wear.
     
  19. B.N.Z.MTNS

    B.N.Z.MTNS 1/2 ton status

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    I haven't noticed anything since I removed mine, but....I live very near the mountains at 5,795 elevation and usually only drive at higher altitudes from there, up to 13,000.

    Secondly, I usually only see my temps climb when I'm chugging up long offroad trails at slow speeds. The air dam is pointless in those slow speed situations. I put a larger radiator in my rig and it hardly ever runs hot now.

    Lastly, I have my old one that you can have for free, it just has the outside corners nipped off. Just send the shipping $$ (or maybe a Rigs of CK5 calender :whistle:) and it's all yours. LOL
     
  20. 4xcrazy

    4xcrazy 3/4 ton status

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    Mothers truck broke down out of town once, it's a '94 Silverado pick up. I pulled it home with a large tow strap, broke lower spoiler into several pieces.

    When I removed it, I didn't have a replacement just yet, we drove that ting around for a few months and I personally did notice it seemed to float more on the highway, wind turbulence was more of a factor while driving without that thing.

    I'm not just saying this to be different, I honestly didn't think they were THAT big of a deal, but after losing the one on her truck and realizing how the handling changed at highway speeds mainly, I bought another one shortly after.

    That truck, by the way, is a standard 2wd at stock height, it's a bit closer to the ground.
     

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