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Front bumper carrier foam insert?

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  • basketcase
    replied
    Originally posted by fronton View Post
    Might be easier and less risky to leave the rear foam in place and set a depth on the tool to cut it out, or take your time with an scalpel. If only a couple pounds can be saved it doesn't seem worth it for the rear. Running a lightweight AGM battery will shed at least 20lb there but how much lighter do you really want the rear to be? I've seen dead weight added to the rear in some instances.
    So the foam doesn't come out easy like the front? I see your point about leaving weight in the rear but I would like to lose weight everywhere. It's free horsepower.

    A lightweight battery is a good idea, a Li battery would be good.

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  • fronton
    replied
    Might be easier and less risky to leave the rear foam in place and set a depth on the tool to cut it out, or take your time with an scalpel. If only a couple pounds can be saved it doesn't seem worth it for the rear. Running a lightweight AGM battery will shed at least 20lb there but how much lighter do you really want the rear to be? I've seen dead weight added to the rear in some instances.

    Leave a comment:


  • Ludwig
    replied
    It's the same for the rear, only getting out may be a bit trickier as you have to bend the lip a bit that holds the rivets in the skin, i don't know how flexible this is on a 30-year old car, i haven't tried it. But the core is similar to the front, as in: you can shed quite some weight by cutting out sections.

    First image shows the lip, second image shows the core in place.

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  • basketcase
    replied
    Originally posted by Ludwig View Post
    it's only held in place by those plastic rivets where you have a pin in the middle that locks the rivet in place when pushed in. Or the other way round, you push out the pin and then pop out the plastic rivet. BMW part number 51111908077, but it's a standard 6mm car-part. If you take these rivets out you can slide the core right out of the skin.
    Thanks for the info. I will do this to mine. Is the rear the same?

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  • Ludwig
    replied
    it's only held in place by those plastic rivets where you have a pin in the middle that locks the rivet in place when pushed in. Or the other way round, you push out the pin and then pop out the plastic rivet. BMW part number 51111908077, but it's a standard 6mm car-part. If you take these rivets out you can slide the core right out of the skin.

    Leave a comment:


  • fronton
    replied
    Nice work, thanks for posting results. Does it come out of the bumper skin easily or are they glued? This mod and fog delete takes a quick 10lb off one of the best places to lose weight. Probably not going to notice that difference but swap a lightweight hood on at the same time and you'll definitely feel the nearly 50lb reduction plus you'd be getting really close to 50/50 weight distribution from 52/48.

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  • Ludwig
    replied
    I think it’s solely for the purpose of cushioning. The skin cracks very easy, i don‘t think a styrofoam backing changes that.

    from 13 to 8,5lbs


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  • bbsrs
    replied
    Originally posted by Ludwig View Post

    There are two cores, one that weighs nearly 12pounds and one that weighs 8 pounds.

    I'm currently in the process of deciding what to do with my core and just found out that i have no foam insert, one of the previous owners must have removed it. I won't cut the core in two pieces as the rest of the bumper hangs off it, but i will cut generous holes, we'll see how much i can remove.
    Anyone know what the purpose of the foam inset is for? Is it purely just to adsorb light impacts of the bumper to avoid cracking of the gfrp skin?

    Leave a comment:


  • Ludwig
    replied
    There is only one core present, but there are two versions of them weighing different. The standard one is the 12lb version, Evo2 and Sportevo had the 8lbs version. I have to admit i have never seen the lighter version, but i guess it's just thinner glassfiber material. It's still availible from BMW #51112230691

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  • fronton
    replied
    Originally posted by Ludwig View Post

    There are two cores, one that weighs nearly 12pounds and one that weighs 8 pounds.

    I'm currently in the process of deciding what to do with my core and just found out that i have no foam insert, one of the previous owners must have removed it. I won't cut the core in two pieces as the rest of the bumper hangs off it, but i will cut generous holes, we'll see how much i can remove.
    Are you saying there were two core options with different weights depending on model year, or each bumper has two cores weighing over 20+ lb? Please do update how much you take out and pics would be helpful as well. I'd love to lose as much weight as possible here but thought my only real option was aftermarket CF bumper.

    Leave a comment:


  • Ludwig
    replied
    Originally posted by fronton View Post

    How much weight could actually be cut out by doing this? I didn't think the core was that heavy, maybe 10 pounds?
    There are two cores, one that weighs nearly 12pounds and one that weighs 8 pounds.

    I'm currently in the process of deciding what to do with my core and just found out that i have no foam insert, one of the previous owners must have removed it. I won't cut the core in two pieces as the rest of the bumper hangs off it, but i will cut generous holes, we'll see how much i can remove.

    Leave a comment:


  • basketcase
    replied
    Originally posted by Mick View Post
    Saving weight in your bumper can be significant. Because it hangs out in front of the axel, it has a lot of inertial effect on turn-in. Not sure it's worth doing uless it's a highly modified car though.
    I'm wondering if it is better to leave the stock bumpers the way they are and buy aftermarket carbon bumpers? Put the stock ones in storage and use the aftermarket ones? I want to do swap most of the bolt on body panels with good carbon repros to save weight.

    Leave a comment:


  • Mick
    replied
    Saving weight in your bumper can be significant. Because it hangs out in front of the axel, it has a lot of inertial effect on turn-in. Not sure it's worth doing uless it's a highly modified car though.
    Last edited by Mick; 01-05-2020, 09:15 AM.

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  • fronton
    replied
    Originally posted by HANDBLT View Post
    and if you want to shed a good bit of weight, cut the plastic holder into two small pieces only where the carrier bolts are. throw the rest away.

    T
    How much weight could actually be cut out by doing this? I didn't think the core was that heavy, maybe 10 pounds?

    Leave a comment:


  • HANDBLT
    replied
    and if you want to shed a good bit of weight, cut the plastic holder into two small pieces only where the carrier bolts are. throw the rest away.

    T

    Leave a comment:

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