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Thread: Center of the Hood vibration..

  1. #1
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    Center of the Hood vibration..

    Drove over 100xxx and it is scary! I have noticed lots of vibration at center of the hood where it is close to windshield, it this normal at speed?

    Mostafa

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    Nope. Are your tires properly balanced? Have they been sitting on one spot for a long period of time? Is your alignment proper?
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  3. #3
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    Have no steering vibration at all.

    Car was on stands for most of the build time.

    I visually see it at right where the high area of the hood is for the wipers.

    Have only driven for few second at these speed.

    I also hear some flapping noise may be in the back, not sure where from these are at speed above 60,not effect by engine RPM.

    I am sure others have had these for one reason or another just trying to get a comfortable feel about driving the car and clean these up.

    Thanks,
    Mostafa

  4. #4
    VRaptor SpeedWorks, LLC's Avatar
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    Your "flapping noise".......did you reinforce the front edge of the aluminum "tray" under the radiator? If not, I would bet money that is the cause of your flapping noise...and that it's now kinked/torn in the center.
    Shane Vacek
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  5. #5

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    Quote Originally Posted by VRaptor SpeedWorks, LLC View Post
    Your "flapping noise".......did you reinforce the front edge of the aluminum "tray" under the radiator? If not, I would bet money that is the cause of your flapping noise...and that it's now kinked/torn in the center.
    This.
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    somehow I hear this from the back but could be from the front, my son was in the car and he said he hears it from front so hopefully this is it.

    Now the front tray by the radiator. the car rubbed on ground few time on driveway and other places, so saturday I decided to check under the car and I noticed exactly what you guys are talking about, so bought a 3/4 x1/8 thick L aluminum and placed inside and across the front edge, so that should fix that and it will be really nice if this also was the noise, what do you guys do here? I have not riveted in place yet.

    That also seems to be the lowest part of the car relative to all other aluminum underbody may be by .5 to 3/4 of inch, os this what you guys have also?

  8. #7

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    I have completely redone the front radiator undertray on the FFR PDG GTM. It is all one piece and flat, along with flat bottom of the car. You will not be able to do this because you likely still have the hinged hood(?). The FFR PDG GTM has an attached to the frame front splitter and a lift off hood. The front undertray is a known issue and what you are doing is the known fix.
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  9. #8
    VRaptor SpeedWorks, LLC's Avatar
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    If you sight down the very bottom surface of the chassis, the pan under the radiator is quite a bit higher than the bottom of the chassis, so that radiator pan should not be the lowest part of the car. The 1/8" thick 3/4" aluminum angle is what we normally use here to reinforce that front edge....just tuck the leading edge of the alum angle inside of the existing lip of the pan and rivet in place.

    Are you saying you already did that, or you cut the piece and never installed it?
    Shane Vacek
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    I cut it yesterday but since I just had surgery I left installation for another day.

    Still not sure why it looks lower, but does not look close to ground so weird, this area sort of goes one way any way, rad only mounts one way, I am not there today but will check more carefully and see.

    Thanks,
    Mostafa

  11. #10
    VRaptor SpeedWorks, LLC's Avatar
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    The front part of the chassis under the battery is angled upwards compared to the rest of the chassis....and the pan under the radiator is lower than the front of the chassis tubes, so that is probably why you were thinking the radiator pan was the lowest part.
    Shane Vacek
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  12. #11
    Administrator 65 Cobra Dude's Avatar
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    For the center of the hood vibration, is the bulb seal on the vertical sides of the radiator up to the cowl touching the underside of hood? My aluminum required cutting to get it just right.

    Henry

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    I am sure you are right Shane, I am just comparing to what is right behind it, I also do know is not any closer to ground as center part of the chassis but really never measure it.

    Henry, I have check these but I will check the seals again, the hole hood assembly is not great, the road I was driving on was not the smoothest road and I have seen on some video there is always vibration on any small bump on center of hood, but not as much as mine.

    Debugging one at a time, hopefully will get most of them.

    Mostafa

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    Drove to my other GTM house, so some update.

    The tray in infact higher than the button may be by 3/4 or so, and as always shane was right, it is the angle behind that make it look like it is lower.

    Got some energy and fixed the pan it looks solid now, so now have to wait for a sunny day for a test drive for noise and hope this helped.

    Thanks,
    Mostafa

  15. #14
    Senior Member jamesfr58's Avatar
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    Mostafa,

    I built a light weight 3/4" square tube frame to stiffen up the radiator pan and keep it from moving under changing air pressure under the car. Here is my solution to making the aluminum in the nose stiffer.

    IMG_1548.JPG IMG_1549.JPG IMG_1550.jpg

  16. #15
    Senior Member jamesfr58's Avatar
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    Did not finish typing before hitting post, brain going faster than fingers..... Hoping to make the front strong as possible and keep air moving through radiator without moving the front hood for lifting or moving or flexing with the change in air pressure moving through the front hood and insure the radiator pan in not moving as air enter the nose of the car.

  17. #16
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    I think your looks good, but I am not sure if you have anything all the way at the front edge, if not I would add an 1/8 3/4 L since this front is the weakest point, after I added that it really looked solid, hope fully this was the noise.

    Center of hood, may have to try a better road first.

    Thanks for sharing. Also may be the only, have no welding tools.

    Mostafa

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