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Body Flex.........................

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Old 12-13-2002 | 01:45 PM
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From: F.H,Waterford,Port Huron, MI
Default Body Flex.........................

I have the BMR boxed SFC and they made a huge differance, but and I jack up the rear of the car and put a jack stand under the SFC rearest point the car flexes. If I look at the door gap at the top by the lock and handle the gap is over 1/4". I am hoping to tie the car in with the 6point cage. Any ideas on this?
Old 12-13-2002 | 04:24 PM
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Default Re: Body Flex.........................

SFC's DO help with 'body flex', but won't eliminate it. A triangulated set will be a big improvement, though, over a set of bars that just run under the rocker panels.

Now if you add a full rollcage, one that extends all the way up to the top of the strut tower from the front of the floorboards in the passenger compartment, then you will have rid the car of any noticable flex.

I have the SLP SFC's that are a 3 pt design and I use then as my jack point so I can get one side of the car up at one time for tire changes at the track without any problem.
Old 12-14-2002 | 04:05 PM
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From: mass
Default Re: Body Flex.........................

Take a look on this site under handling and braking KBDD SFC or BMR SFC.The pictures show an intermediate stage of a car that with a floor jack in just the right place can pick up three wheels and open and close both doors without binding.
Old 12-14-2002 | 04:57 PM
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Default Re: Body Flex.........................

The KB SFC will not fit on my car. There is no room with the 3" exhaust I was going to weld 1" square tubing on the interor of the car on the floor. But not that much tubing.
Old 12-15-2002 | 08:30 AM
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Default Re: Body Flex.........................

You can accomplish a lot by grinding off the undercoat on the outside of the pinch welds under the doors and welding 1 inch galv. steel about 51/2 feet long to the bottom of the chassis and to the pinch welds. Then use the same 1 inch box to make attachment points from the now rigid pinch welds to the sub frames, closest to the wheel wells.Will act like a home made SFC and would still leave room to fabricate a similar rail on the inside of the pinch weld that could directly connect the sub frames.One inch pieces of flat stock welds the inside rail to the outside rail and you'll have something super strong that's added maybe 12 lbs. Use black silicone to seal the ends and spray with undercoat and they'll be invisible.
Old 12-15-2002 | 09:51 AM
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Default Re: Body Flex.........................

Thanks SCOT I will keep this in mind after the cage install. And what are you building your car for that you are doing all that reinforcement?
Old 12-17-2002 | 12:52 AM
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Default Re: Body Flex.........................

I wanted a car that was precise and capable.Like driving something telepathic.A metaphore for a quality thats hard to define. Immediacy. To get it I knew I'd have to build it myself if I didn't want to spend a fortune.A former Florida police car bought and modified for less than $11,000.Looks like an aging 6 cylinder camaro.Is a rigid platform,6 speed, 2 seat, high power to weight ratio, neutral handling equal in solidity and performance to a car that cost many times as much.
Old 12-17-2002 | 07:14 PM
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Default Re: Body Flex.........................

I have the BMR boxed SFC's welded in, BMR STB, and a Wolfecraft 6pt bolt-in cage. The car feels like one piece now. If I jack in the middle of the SFC on the driver side, the passenger side actually lifts somewhat too. I jacked under the front of the driver side SFC the other day, and if I kept going, it looked like 3 wheels were going to come off the ground.
Old 12-18-2002 | 06:54 AM
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Default Re: Body Flex.........................

Teutonic,I found I needed to do a lot of rear chassis work including rear shock tower and wheel well bracing and that once I got the chassis stiff I needed to soften the rear suspension to get the handling neutral.19mm bar, 3rd gen Bilsteins,stock springs in the rear compared to 35mm bar, 1LE springs, Strano revalves front.How about you?
Old 12-18-2002 | 11:50 AM
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Default Re: Body Flex.........................

scot,

i feel the handling has been getting better and better, but i have not had it to the track yet, so i can't really tell you. Bilstein HD's are my next mod, are you telling me they will be too much?
Old 12-19-2002 | 04:24 PM
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Default Re: Body Flex.........................

Teutonic, What I found was that the 4th gen Bilstein HD actually has less rebound and comp. control than the 3rd gen Bilstein HD. As I use stock 114 lbs. linear rear springs the 3rd gens were a better choice for damping. Soft spring and 19mm bar keeps the rear tires following the roads irregularities and the aggressive damping keeps them planted.Once the chassis is rigid enough, the rear suspension can leaverage against it and take a set while being soft enough not to generate skittish oversteer because of a rough road surface.My front suspension, 360 lbs. linear springs and 35mm bar, can then be appropriately stiffer with Bilstein's revalved for even more damping than either 3rd or 4th HD, and the difference between front and rear suspensions balance out a nose heavy car.



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