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Discussion Starter #1
Back in 95 I box welded the open sections of 94 SS frame to no apparent benefit. Has anyone explored a more sophisticated frame strenthening, especially around the front and rear suspension attachment points?
 
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Discussion Starter #2
While this is not renforcing the frame it may help you. Are you familiar with the body bushing mod? Did you know GM left out many of the lower body bushings between the wheelbase? Adding these bushings and making sure they actually contact the frame can make the car feel much tighter.
 
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Discussion Starter #3
96capriceMGR, That was one of the best improvements ever made to the car. I used the lowers from Dal and the 9c1 uppers. Total cost about $135. Vastly better steering perception, less body roll, less understeer, faster turn in and the car felt stronger and heavier at the same time more tossable as if it was lighter. Sounds contradictory but isn't. It's that direction I'm hoping a stiffer chassis will take the car.Question really is how to make the suspension attachment points more rigid because less flex there will have a similar effect on perception even it doesn't make the car one bit faster in terms of a lap time.
 
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Discussion Starter #4
I have not seen anything aimed at legitamately stiffening the frame, since we started with a full steel frame our cars are already ahead of many in this department. There is at least one engine bay brace available which is purely cosmetic for us, for unibody car a strut tower brace can help a lot. What are your other mods? I wonder if it is time for you to look at things like Global West Delalum(SP?) "bushings" they replace different bushings and are more like a Heim joint(best comparison I could think of) in that it is solid pieces that slide against eachother so you have the twisting like a bushing but without deflection. Another MUST do is the rear lower control arms lots of choices all much better than stock, if you have not done this yet it will make a huge improvement.
 
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Discussion Starter #5
Put Del-A-Lum bushings in the front end...made my car feel WAY lighter, and MUCH snappier/responsive/tossable. I can't wait to get a set of global west LCA's for out back as well...the zero deflection bushings are AWESOME. No bind suspension is the best kind of suspension. I honestly don't think reinforcing the frame mounting points will seem like a big deal at all when you get into things like that. Also bigger swaybars that keep the body level and more controlled make the car turn in faster and feel much more responsive.

Being a 9C1, my car already has full body bushings, and I plan on at the very least replacing them at some point, undecided if I'm going to upgrade. The Del-A-Lum bushings in the front end made a VERY VERY noticeable difference the very first time I pulled out of the driveway with them installed. I pulled out and yanked the wheel like I am used to doing to make a hard right when starting out...and the car reacted MUCH quicker than I had thought it would...much lighter feel, much more responsive to what I was doing with the wheel...they were expensive, but VERY VERY worth it.
 
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Discussion Starter #6
96capriceMGR, Having done a lot of suspension experiments, I was looking to focus on the chassis for a while. Every generation of the Corvette for instance has been engineered with a more rigid platform than the last.C5 was much stiffer than the C4 and I've been reading about how the C6 chassis will be by far the most rigid yet.It's the reason the Z06 is only built as a hardtop. Makes sense when you see the trend in supercars and racecars using carbon fiber and structural adhesives. On my now two seat 98 B4C Camaro I used a structural adhesive called Dynaplate to reinforce the sub frames on the inside of the car,built a full frame underneath, triangulating shock tower brace front and two point rear, wheel well and floor braces, hoop and arms where the back seat used to be. Hoop welded to the frame. Put a jack in just the right place and you can pick up three wheels and still open and close the doors without binding. Steers like no F-body I've ever seen, but the ride and handling are both vastly better, because the suspension can do it's job without flexing the chassis or torqueing the body.On northern New England's frost damaged roads it's tighter than a friends Testarossa, which is a testament to what modern materials can accomplish. So I've ignored the Impala's chassis while learning how far I could take the Camaro's, but now I want to see just how much a B-body frame can be improved. I'm convinced that it's real easy and a mistake to have too stiff a suspension, but there is no such thing as too stiff a chassis.
 
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Discussion Starter #7
Guess what we really need is a structural engineer, to look at where frame flex is occuring and what the most effecient means possible is to reduce the flex.
 
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Discussion Starter #8
scot, I've had some thoughts along this line as well-you said fully boxing the frame has no real benefits? There goes one idea! I was also wondering if the rear braces that fit between the rear upper and lower c.a's forward mounts for a Chevelle would fit/help. (I'll find a link in a bit). Another idea-and I am REALLY not sure about this-wouuld be solid body mounts. The only reason I think about this is I have a '71 Camaro that has GW solid subframe mounts, and they are great! Tightens up the whole front end, and dosen't affect the ride at all. I looked and GW does NOT offer solid mounts for Chevelles, so I had assumed it was a bad idea for a full frame car. But tying the body to the frame directly would sure seem to stiffen things up. I know what you're saying, new car manufacturers are making a lot of fuss over how stiff their chassis are.

Oh and I can also vouch for the Del-a-lums, they are THE BEST!!
 
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Discussion Starter #10
I almost wonder if it is just time for a well engineered rollbar or bepending on usage and your tolerance level maybe even a cage.
 
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Discussion Starter #11
protour4ever: a while back there were some posts talking about solid body mounts. Defiant tried it in his car, using some aluminum bushings made up by Navy Lifer, but there was no follow-up that I'm aware of. There was some concern that this would transfer too much stress to the body leading to things like broken windshields, but there was no data or real world experience to back that up. See here. If Navy Lifer still has this in the works, maybe he can let us know. Also, stiffening up the body panels the way scot describes would probably help address this concern.

scot: Is the Dynaplate you're talking about the stuff that Dynamat makes for sound dampening? I'd be interested in learning more about what you did to that Camaro if you have a website or something. Sounds cool.
 
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Discussion Starter #12
The Dynaplate is made by the same company that makes Dynamat sound deading, but is a very different product.Dynaplate is a light weight panel of aluminum with a pressure sensitive viscous adhesive backing.When applied to metal it creates a structural reinforcemnt by creating a sandwich that can be covered over with a product like Dynamat extreme.The net effect in the F-body is where the sub frames are welded to the floor becomes more resistant to twisting under load. This is subtle effect, but that project is an ongoing experiment in chassis rigidity. It's more effective to use one inch square floor and wheel well braces. The solid, or even poly body mounts do have some disadvantages but along with the bracing potentials, they are on the table for consideration. Roll bars and cages for a street car are a disaster looking for a place to happen. It's why the Camaro has a deleted rear seat. You NEVER want to be in caged car without a helmet if your head could get even close to the bars. Fatal for back seat passengers. Period. Even tagging a curb at low speed has lead to fatal head injury. Talk to any trauma surgeon. Immovable objects and small contact points and low velocity is why large caliber bullets going real slow = corpse. So tha Camaro has the hoop so far back there is no way a belted front seater can make contact.And roll bar padding is a joke when you look at the force curves involved at even low speed.But all this brain storming is great, so lets keep it up.
 
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Discussion Starter #13
scot, after reading some of your posts from the last day or so I see you are already know a lot and your car is well modded. So my answers were aimed at someone who is more of a beginer than you are. We have alot of guys come here completely green and start asking questions about things they are far from ready for like guys with stock cars wanting to throw big cams in without any of the necessary stuff. At least they ask before doing, my answer to you were geared more that way since I have not seen you active before, a sig that includes a good list of your mods can help signifigantly in getting good answers to questions.

On to the chassis stuff, what about front and rear braces to better tie the sides of the car together. For that you could just cough up some spare tire clearance and run a bar from spring pocket to spring pocket in back, this of course would mean cutting the trunk floor to get through. You would also need to make the hole large enough to allow some independant body/chassis movement, I think something like a shifter boot could be used to keep the elements out of the trunk yet allow movement. A strut tower brace(I know we do not have struts or towers) sort of thing in front would be much easier you would have to again build it since the only one offered comercially is cosmetic. It would be interesting to first figure out a way to measure the chassis flex in front before and after. Might be as easy as driving the car through the same curves with zipties on the shock shafts to see how hard the suspension had to work before and again after????? Heck even a trailer hitch could help stiffen the rear.
 
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Discussion Starter #14
How about adding additional lateral cross braces like the one under the transmission. You could get these from the salvage yard and bolt or weld them in. This plus the Edlebrock 'tubular braces' and the HD body cushions should reduce chassis flex.
 
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Discussion Starter #15
What about the Clear Image tubular tranny crossmember it might be stiffer than stock and will drop some weight which is good especially if you other ideas add weight.
 
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Discussion Starter #16
This is a great thread! Everyone wants to know what can be bolted to the frame without thinking about strengthening the foundation. What about a length of square tube bolted to the front and rear frame horns at the bumper shocks, like the well known Buick frame brace except stronger. I like the idea of the tranny crossmember being used, but I don't think the CIA/BTO piece is nearly strong enough. Something more along the lines of what Kyle Tucker did here- http://www.detroitspeed.com/TwisterConstruction.html -and scroll to the trans crossmember description.

scot, great points about the roll cage- I don't want to wear a helmet every time I drive!!

Also, here is just some food for thought about strength and safety. http://www.hotrodstohell.net/chevelle_crash/wreck.htm
 
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Discussion Starter #17
I have some pictures of the full frame and chassis reinforcement that I've done to my Camaro.It's the basis for my experiments with the Impala.Full frame car ought to be easier to get to the same point the Camaro is now. Stock F-body, even the hardtop, is a wet noodle, so weak that you'll often see stress cracks in the paint and sheet metal dimples in the rear quarters because engine torque can twist the unibody so much. What the pictures show has changed the car radically, especially in the perceptions of steering accuracy, linearity of break away and the dynamics of acceleration and braking.Ultimate cornering ability is increased because the suspension now has rigid leaverage points.I do not have the ability to host them however.So if any one is interested and can host them to this site,I will email 3 or 4 pictures to you.
 
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Discussion Starter #18
Frames don't bend front to back nearly as much as they twist.

The body twisting or bending is another matter, and I'm willing to bet that body flex/twist is as bad a source of misinformation to the driver, as frame flex/twist.

I also don't understand why no one has bothered to even come out with a torque arm for us yet. It certainly couldn't hurt.
 
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Discussion Starter #19
This thread is really about two seperate problems. The frame needs to be stronger, reinforced at the suspension attachment points,braced between L+R at both ends of the car,possibly cross braced in the middle.Gussetted as needed.This weekend I will start by removing the ineffectual boxing of 9 years ago.1/8 inch sleel shaped to insert in the F+R pockets before the wheel wells, L shape, extenting as close together as space for inserting will allow,then same material to fill the space, and weld it all together.Make a strong attachment point for additional body mounts. Get that done right before I even attempt any of the other frame stiffening. The second problem is the body. It needs to be stronger and stiffer as well.The Grand National site,www.TurboBuicks.com, has some horror stories of similar problems and metal or poly bushings don't seem to be the answer.Body is too weak for the loads transmitted to it. Squeaks, rattles, vibration tell you it's the wrong choice.Cracks in the roof , above the doors and in the rear quarter, with or without bushing upgrades.Only fixes for a street car has been X-bracing behind the rear seat, trunk and under hood fabrications.Floor bracing on the underside.Race cars get the cages of course.I'm looking at a long winter project.
 
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Discussion Starter #20
Originally posted by Cheavy:
Frames don't bend front to back nearly as much as they twist.
While I won't deny that these cars twist very easily, I would argue that the bending isn't a problem. Toss the front end of my car up on jackstands located behind the front wheels, and it becomes difficult to get the passenger's side door opened. There's a lot of bending going on there.

Anyone explore seam-welding the body?
 
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