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    Senior Member fatbillybob's Avatar
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    Default Ballast

    How are you guys safely securing ballast in your racecars? Remember a simple crash with 35mph delta is 20g's. My solution...
    ammocan.jpgammocan2.jpg

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    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    I the NASA and SCCA regs call for minimum grade 5 but we always use 8.8's. I get special extra thick fender washers and taller, larger od nuts from mcmaster to back them up.
    We run up to 150# and yeah, I'd sorta like for it to stay put if I hit something.
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    Administrator ucfbrett's Avatar
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    I would think steel plate is also worth considering. You can buy it in varying thicknesses and it keeps the CofG lower inside the car.

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    LongWinded National Champ Bueller's Avatar
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    What kind of ballast container is that?
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    Senior Member fatbillybob's Avatar
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    I use lead in the ammo box. I can ballast zero to 75lbs in there maybe 100lbs. In my case I welded the box to the lower rollcage support then bolted the frame to the OEM seat anchors to further hold the box and its contents. I figure the seat anchor is engineered for a big fat guy at 20g's. I already have a 40lb steel plate in the car too and it is big. Steel is not as dense and heavy per volume of it once you start playing with lead. Besides I can always make bullets out of the lead later. Yes I always hear lower is better when it comes to weight in the car but what is the real value of say taking a battery 50lbs out of the engine compartment and putting it in the passenger floor and even gutting out the A/C that is relatively high in the car and moving that weight as ballast on the floor? That could be 100lbs of things you could get low. Is the effort worth it? What does that mean??? a 10th? a second?

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    Administrator ucfbrett's Avatar
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    I don't know what it translates to on a lap timer.

    I race a Spec Miata and every gain is a minimally incremental improvement.

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    Senior Member bellwilliam's Avatar
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    It is. I've tracked a Prius, it feels really strange with all the weight down low.
    Also for Volt and Tesla (batteries not only low but between both axles, makes it effectively a mid engine car), handling really does feel great. Strange feeling first few times taking a corner at speed
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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by fatbillybob View Post
    I use lead in the ammo box. I can ballast zero to 75lbs in there maybe 100lbs. In my case I welded the box to the lower rollcage support then bolted the frame to the OEM seat anchors to further hold the box and its contents. I figure the seat anchor is engineered for a big fat guy at 20g's. I already have a 40lb steel plate in the car too and it is big. Steel is not as dense and heavy per volume of it once you start playing with lead. Besides I can always make bullets out of the lead later. Yes I always hear lower is better when it comes to weight in the car but what is the real value of say taking a battery 50lbs out of the engine compartment and putting it in the passenger floor and even gutting out the A/C that is relatively high in the car and moving that weight as ballast on the floor? That could be 100lbs of things you could get low. Is the effort worth it? What does that mean??? a 10th? a second?
    Have someone fast drive your car, find out how much time you're missing due to driver, then decide to keep the A/C after all

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    I use lead in the ammo box.
    So you are using live ammo as ballast? Don't want to be near you when you crash . . .

    P.S. The NRA sticker is still on the Suburban.
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    Chest hair required Olitho's Avatar
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    Quote Originally Posted by Richard EVO View Post
    So you are using live ammo as ballast? Don't want to be near you when you crash . . .

    P.S. The NRA sticker is still on the Suburban.
    I always travel with about 1500 rounds. I don't want to be on track and come in to pit just to find out the Zombie Apocalypse has struck while I was racing.
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Quote Originally Posted by emilio700 View Post
    I the NASA and SCCA regs call for minimum grade 5 but we always use 8.8's.
    FYI, you're using basically the same since grade 5 SAE is roughly the equal of Metric 8.8.
    Grade 8 SAE is roughly the equal of 10.9 and ASTM A579 is roughly 12.9.

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    Quote Originally Posted by Blackbird View Post
    FYI, you're using basically the same since grade 5 SAE is roughly the equal of Metric 8.8.
    Grade 8 SAE is roughly the equal of 10.9 and ASTM A579 is roughly 12.9.
    I could swear NASA specifically wanted Grade 5. I use grade 5 but typically larger sizes than specified in the NASA CCR.
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    Quote Originally Posted by Blackbird View Post
    FYI, you're using basically the same since grade 5 SAE is roughly the equal of Metric 8.8.
    Grade 8 SAE is roughly the equal of 10.9 and ASTM A579 is roughly 12.9.
    We have been using 3/8-24 8.8 SAE fasteners but in greater qty than required per lb. My napkin math shows our ballast is a bit more secure than SCCA/NASA regs require.
    I think having the fastener pull through the tub is a greater risk than than the fastener actually yielding.

    These are the washers I used most recently, stacked. They're stainless so that helps resist corrosion on the outside.

    92303a105l.gif

    nylon insert flange head lock nuts

    93298a130p1s.png
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    Señor Member b3d3g1's Avatar
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    I used grade 8 hardware and made a backing plate out of a 3/16" sheet of steal with the same hole pattern in it. Then used oversized washers with the backing plates and weight. My weight straddles a frame rail so I have 2 backing plates.
    I'm thinking about making something that bolts into the factory passenger side seat mounts since I won't be using ballast and a passenger seat at the same time. The only problem is I have absolutely no idea what load the seat mounts can handle in a crash.
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Quote Originally Posted by emilio700 View Post
    We have been using 3/8-24 8.8 SAE fasteners
    What does the marking on the head of the bolt look like?

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    Quote Originally Posted by Richard EVO View Post
    So you are using live ammo as ballast? Don't want to be near you when you crash . . .

    P.S. The NRA sticker is still on the Suburban.
    No silly...I have lead in the ammobox not bullets. The ammobox was just a convenient way to contain varying amounts of lead. But I always have bullets nearby...

    Good on the sticker. I think I'll get you a subscription for the NRA then ,monthly, you will have "The American Rifleman" for your coffee table and more stickers for your Jag and FM. What is your address?
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    Senior Member fatbillybob's Avatar
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    Quote Originally Posted by b3d3g1 View Post
    I'm thinking about making something that bolts into the factory passenger side seat mounts since I won't be using ballast and a passenger seat at the same time. The only problem is I have absolutely no idea what load the seat mounts can handle in a crash.
    I think more thought needs to go into unengineered attachment of ballast. The meager rules of NASA/SCCA make sure the attaching bolt won't fail but says little about what the bolt is attached to. I run over 120lbs of ballast. Just one 25LB block of lead in a 20G 35mph delta is 500lbs. My 120lbs is 2400lbs. If one sticks a floorjack under their floor pan which is the typical place to bolt ballast to the pan will surely deform. That is not good. So your idea of using extra support is a good one. On the seat anchors my wag would be 1000lbs per anchor. I figure the seat anchors are designed for a 200lb guy, 20g crash=4000lbs with 4 anchors =1000lbs. I think that is pretty conservative. That is why I also brought my seat anchors into play on the ammobox.

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    Señor Member b3d3g1's Avatar
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    Quote Originally Posted by fatbillybob View Post
    I think more thought needs to go into unengineered attachment of ballast. The meager rules of NASA/SCCA make sure the attaching bolt won't fail but says little about what the bolt is attached to. I run over 120lbs of ballast. Just one 25LB block of lead in a 20G 35mph delta is 500lbs. My 120lbs is 2400lbs. If one sticks a floorjack under their floor pan which is the typical place to bolt ballast to the pan will surely deform. That is not good. So your idea of using extra support is a good one. On the seat anchors my wag would be 1000lbs per anchor. I figure the seat anchors are designed for a 200lb guy, 20g crash=4000lbs with 4 anchors =1000lbs. I think that is pretty conservative. That is why I also brought my seat anchors into play on the ammobox.
    My thinking is that the seat anchors don't actually see that much load in a crash. The stock belt would take the load of the passenger and the mounts are just holding the seat in place. Probably not a lot of sports car oem seats are anywhere near 100 lbs which is why I have 2nd thoughts. I'm pretty sure the mounts are just spot welded to the floor anyways which isn't that comforting to begin with.
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    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    Quote Originally Posted by Blackbird View Post
    What does the marking on the head of the bolt look like?
    Dunno. SAE grade 8 8 from mcmaster.
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    Senior Member fatbillybob's Avatar
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    Quote Originally Posted by b3d3g1 View Post
    My thinking is that the seat anchors don't actually see that much load in a crash. The stock belt would take the load of the passenger and the mounts are just holding the seat in place. Probably not a lot of sports car oem seats are anywhere near 100 lbs which is why I have 2nd thoughts. I'm pretty sure the mounts are just spot welded to the floor anyways which isn't that comforting to begin with.
    Ahhh...you are right my brain fade. In some cars you are 100% correct. The trend these days is to integrate the seatbelt into the seat. So in those cars that have a belt anchor on the seat I assume that the chassis anchors will take the load of a 200lb guy. My vette is that way but even so I still welded the ammobox to my lower cage support. I think future seats with have all seatbelts integral with the seat. There are good structural reasons to do this. That of course will mean the chassis anchors need to take the load of the average 200lb guy + seat + some level of over engineering or some factor like the 95th percentile weight. In your case a light oem seat is 30lbs and at 20gs that's 150lb/anchor. So in the space of say 14" between anchors it would be pretty easy to bolt down a 25lb ingots of lead to those anchors and feel pretty good about it. 4 anchors gives you 50lbs.

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