So it sounds like those that disagree are saying I need frame connectors for my ‘66 Valiant 273 four door to drive it on the street; I do have radials on it.
I am really surprised this didn't kick up
- Thread starter Princess Valiant
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moparmat2000
Well-Known Member
You are trying the sub frames front and back together, and to the floor. Using thicker steel than the rockers are, which is essentially your framerail. This severely lessens body twist.
Ask anybody building a big block A, B, E body car if their car benefitted from this mod.
Look at pix of my 67 below. You tell me if this doesnt make sense to you from a stiffen it up standpoint. 2x3 box steel 1/8" thick. Front and rear torque boxes made from 1/8" steel plate.
Anybody who thinks that they can update everything to modern suspension and tires and not stiffen up the chassis and it will handle just fine is an ID10T. I like Tony's posts on YouTube, but he is more of a purist. Some of the cars he knocks for not being original this or that. Some of which, i would have no problem with. He was knocking a white 67 fastback cuda for stuff easily fixed or changed. I wouldent kick that out of my garage.
Ask anybody building a big block A, B, E body car if their car benefitted from this mod.
Look at pix of my 67 below. You tell me if this doesnt make sense to you from a stiffen it up standpoint. 2x3 box steel 1/8" thick. Front and rear torque boxes made from 1/8" steel plate.
Anybody who thinks that they can update everything to modern suspension and tires and not stiffen up the chassis and it will handle just fine is an ID10T. I like Tony's posts on YouTube, but he is more of a purist. Some of the cars he knocks for not being original this or that. Some of which, i would have no problem with. He was knocking a white 67 fastback cuda for stuff easily fixed or changed. I wouldent kick that out of my garage.
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451Cuda
Well-Known Member
I've seen a Road Runner that was so twisted up that there's a buckle in the roof and the doors don't shut. This was a violent 4 speed car with no cage and no frame connectors. It was undrivable and basically scrap at that point. The guy ended up getting a different body and transferring all his parts over, and he definitely put connectors and a 6 point rollbar in the replacement.
If ANY car has a good amount of power, put frame connectors in - my .02.
If ANY car has a good amount of power, put frame connectors in - my .02.
moparmat2000
Well-Known Member
You dont have to. A stock 273 more door valiant sedan you wont notice any difference if all you did was radials. Also a more door has a stiffer body than a hardtop since it has posts for the rear door hinges.
However if you put in a hot 360, or a 450HP 408, beefed up automatic, or a stick shift, maybe upgrade the suspension with 1&1/4" front sway bar, poly bushings, boxed LCAs big block torsion bars or bigger, it is something your going to want to do to get stiffness back into it with a better suspension and increased power levels the factory didnt dream of for its design.
ir3333
Well-Known Member
I see your point in continuing the frame front to rear with similar size square tubing and this should almost act as a full frame under the unibody.
Certainly a benefit to a vehicle driven and launched hard.It would seem that the x member forward would need beefing up accordingly?
The smaller 3 sided or 2"x 2" tubing not so much.
Certainly a benefit to a vehicle driven and launched hard.It would seem that the x member forward would need beefing up accordingly?
The smaller 3 sided or 2"x 2" tubing not so much.
Well, I don't know what to tell you. Do you go to the drag strip? If you do, go through the pits. See which cars have connectors and which do not. Pay attention to them as they launch, remembering which have them and which do not. You'll see a huge difference. And I'm not talking about 13 second cars either. I'm talking about the ones that can hang the hoops.
Now, I do agree with Tony on one thing. The frame rails are connected to the rockers.....and that's good. But it's still no substitute for being connected front to rear.
In some cases, yes. Have you looked on the US Car Tool site? Look at their complete chassis stiffening kits and you'll see what all comes in it. It's pretty impressive. Very good stuff for a high horse power car.
TrailBeast
AKA Mopars4us on Youtube
I think you might feel different about that once you felt the difference in how much more solid and stable the car feels.
Of course triangulation is way stronger, but it's a lot more complex to do as well.
moparmat2000
Well-Known Member
If your thinking of the US car tool ones. They get seam welded to the underside of the floor pan boxing them in making them very strong. I didnt have $200 for em, plus I installed a shortened 74 dart floorplan in my 67 barracuda to replace floor rot and repair a previous owners hack butchery. Was not sure all the bumps in the US car tool ones would line up since my floor pan wasnt a 67 barracuda pan.
My connectors are tied in all the way back to where the framerail kicks up, the rear torque boxes overlap the connectors which overlap the rails. I slotted the floorplans in the back to run them thru, and opened up the box steel to overlap the rear rails, as well as adding in 3/4" water drain holes. They stick up only 1/2" thru the floor. Since pix were taken the floor has been welded to the subframe connectors. Additional padding on either side before I put carpet down and you will never know unless you look underneath the car.
They are welded to 1/8" lap transition plates that are then welded to the torsion bar crossmember. This transitions the load better than welding an 1/7" thick 2x3 box member directly to a thin trans crossmember. My pic, they are temp installed with clecos prior to welding. You can see how adding the transition plates will allow the load to go into the crossmember without cracking once welded up.
Since this is a street car I relocated my parking brake cable routing to lay inboard of the LH subframe connector. It now runs straight to the rear, and not having to have it cross over or under or through the connector is a better way of doing this.
My steel tube cost me $40 for a 12' stick, and was able to do them and the rad support. I did it on the cheap, looks good IMHO, head on down the road. If I was restoring this car stock I wouldent have bothered with any of this. Change the hacked up torsion bar member, and floor pan, and done. However it was a slant six 3 on the tree bench seat no option barracuda sports coupe. I bought it because it was cool looking, inexpensive to get back into the hobby after 20 years, and it had 3 pedals needed for a 4 speed conversion. All I wanted out of it was the body some suspension bits like the LCAs and clear title. All the slanty **** went right on the scrap trailer.
moparmat2000
Well-Known Member
My sons 69 cuda is an ex drag car from the late 80s early 90s. They used 2x2 box steel. I am not too happy about the way it was done, so we will be redoing it the way my 67 is done using 2x3 box steel and installing them before the new floorpan goes in. I made cardstock templates for every mod I have done on my 67. Easy enough to make copies of all of it for his car.
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A guy on the internet makes a video, uses some technical jargon, and appeals to your common sense. He must be right, right?
Well, no. He isn’t educated or trained on the topic of his video. He doesn’t have the knowledge to back up the claims he’s passing off as fact. Sure, there is in fact some truth to some of the things he’s saying, but sometimes the details are REALLY important.
Engineering doesn’t always follow common sense. It’s damn complicated. And some of that is knowing when certain principles apply. There are 100% legitimate engineering principles and equations the simply DO NOT apply in certain situations. Knowing a few basic principles is good, but it doesn’t mean you’re an engineer.
This is like all the arguments about which kind of subframe connectors are best too. Until someone runs a finite element analysis, no one here can actually know.
Well, no. He isn’t educated or trained on the topic of his video. He doesn’t have the knowledge to back up the claims he’s passing off as fact. Sure, there is in fact some truth to some of the things he’s saying, but sometimes the details are REALLY important.
Engineering doesn’t always follow common sense. It’s damn complicated. And some of that is knowing when certain principles apply. There are 100% legitimate engineering principles and equations the simply DO NOT apply in certain situations. Knowing a few basic principles is good, but it doesn’t mean you’re an engineer.
This is like all the arguments about which kind of subframe connectors are best too. Until someone runs a finite element analysis, no one here can actually know.
Back in the 80's, 90;s I restored more than a few 440 B and E bodies 4 speed cars, usually 3:55 geared. All had been run hard, I remember especially the B body ones have some pretty good body flx, not so much with the E bodies.
Some run with slicks, cheater slicks and all street tire back in the day were different than today .
The ridigity of these cars comes from the roof, floors, and rockers. The subframe is a platform to hold the drivetrain and suspension, We are also talking of cars now that are what around 50 yrs old, Even the cars that have not lived in the rust belt have thinner metal, everywhere!!!!
Torque boxes were a must for a vert. Hemi and 6pa E bodies had torque boxes. I understand Tony's argument, and maybe he s correct. I am no engineer.
I bet the engineers made thee cars as cost effecient as possible, and the cars had a life of what 6 years on average, then they became a wore out car, a half used up second car, or junker. Time for Joe to buy the new latest model!!
moparmat2000
Well-Known Member
I copied their 1/8" plate torque boxes with some minor changes for my application. I like some of their stuff, but think their lower road support stiffener is cheesy compared to what I built.
ir3333
Well-Known Member
Is that kind of stiffening a benefit on overpowered street driven cars that just break the tires loose, unlike a purpose built drag car with slicks that hooks on launch and stresses everything to the 9's?
As for handling, I've seen cars just add stiff t bars, springs and shocks driven on 21570's that will understeer right off the road when pushed if your not careful.Drastically increasing the chassis stiffness on these cars requires some thought and maybe further modifications to keep it safe.
As for handling, I've seen cars just add stiff t bars, springs and shocks driven on 21570's that will understeer right off the road when pushed if your not careful.Drastically increasing the chassis stiffness on these cars requires some thought and maybe further modifications to keep it safe.
DrEamer
I suffer from cars on the brain!
Great discussion here, I'll just throw a few more thoughts out there. Fifty years ago, every American car manufacture that I know of built unibodies the same way, without frame connectors. I'm guessing that was just the engineering school of thought of the day. Subframe connectors most likely came about because problems, or perceived problems, that people were having caused the the factors mentioned above. So much has changed over the last 50 years, that it is hard to keep track of it all. First, engineering has been able to increase the strength of modern vehicle both metallurgically, and structurally. Todays metal is both lighter and stronger. Also, the modern unibody is strong enough use on SUV's which weighs a lot, and have higher centers of gravity which puts a lot more load on them.
I think it interesting how the aftermarket has tried to improve our cars. A company like Hotchkis uses connectors, but QA1 does not. QA1 sells a tubular K member, but Hotchkis does not. Neither of them sell torque boxes, core supports, or under fender supports, but US Car tools and XV racing does. Everyone of these companies have some sort of engineering behind their product. Whether or not one is better then the other is hard to tell. The one solid case for connectors the David Rea brought up in one of his recent videos is when a k frame is that uses coil over shocks that do not connect to the factory shock towers. His point was by doing so, that style of K member put more stress on the car because it no longer connects to the factory engineered strength of the shock tower and torsion box. It seemed to make sense to me, but who knows. That said, I know some of the aftermarket bolt on front members used in it the early Mustangs and Falcons broke off at the mounting points because they did not connect to the towers. Anyway, food for thought.
I think it interesting how the aftermarket has tried to improve our cars. A company like Hotchkis uses connectors, but QA1 does not. QA1 sells a tubular K member, but Hotchkis does not. Neither of them sell torque boxes, core supports, or under fender supports, but US Car tools and XV racing does. Everyone of these companies have some sort of engineering behind their product. Whether or not one is better then the other is hard to tell. The one solid case for connectors the David Rea brought up in one of his recent videos is when a k frame is that uses coil over shocks that do not connect to the factory shock towers. His point was by doing so, that style of K member put more stress on the car because it no longer connects to the factory engineered strength of the shock tower and torsion box. It seemed to make sense to me, but who knows. That said, I know some of the aftermarket bolt on front members used in it the early Mustangs and Falcons broke off at the mounting points because they did not connect to the towers. Anyway, food for thought.
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moparmat2000
Well-Known Member
Agreed barbee6043. They were made with a life expectancy of 10 years and 100k tops. At 5 years old they were half worn out, now second hand used cars. Stuff back then wasnt built to any quality standards like today. Heck I have an 11 year old 2008 Chevy HHR 5 speed daily driver with 119k on it. No rust holes. Paint still shiny and I dont wax it. Still runs like brand new. A/C still blows ice cold. I run the snot out of it daily, load the *** end full of stuff all the time. Only things I have done to it this whole time since I bought it new was change the oil, the filters, front brakes, tires, thermostat, spark plugs, various light bulbs, 1 battery, and one set of front wheel bearings. Normal wear and mtx ****.
I havent made a car payment in years. I will keep running it till something major goes that's too costly to fix. Currently the flex pipe to the converter developed a crack at the flex joint. A new pipe w joint and new converter was $109 gaskets at both ends, an hours time to change out.
Point I am trying to make is cars are engineered to last longer these days. With Japanese quality upping the bar, now customers rightfully demand it from any make they buy. If I get another 5-7 years out of this thing and hit 200k before its junk, I will be really happy.
I havent made a car payment in years. I will keep running it till something major goes that's too costly to fix. Currently the flex pipe to the converter developed a crack at the flex joint. A new pipe w joint and new converter was $109 gaskets at both ends, an hours time to change out.
Point I am trying to make is cars are engineered to last longer these days. With Japanese quality upping the bar, now customers rightfully demand it from any make they buy. If I get another 5-7 years out of this thing and hit 200k before its junk, I will be really happy.
I guess one clue to this, is what is done to Nascar and the big time drag cars? Rigidity, safety, performance...
Yes, that kind of stiffening is a benefit on street driven cars. Again, you're dramatically underestimating the difference between the skinny bias ply's these cars came with and the radials that most people with these cars run. Almost no one runs tires as skinny as what came from the factory. I would say that most people are probably doubling the amount of grip compared to the factory set up.
But how many of them double the wheel rates with larger torsion bars to deal with that grip? How many of them consider what doubling the suspension loads does to the chassis? Instead we get guys running radials that are way bigger than the factory ever designed for arguing that the factory knew best. Well
As for the second part of your post, yes, you can go overboard with suspension and chassis stiffness if you just run 215/70/15 BFG's on there. And that can put you into oversteer, sure. The suspension and chassis has to be considered as a system, and that starts at the tires. You build the suspension for the grip that you have.
But even those 215/70's have twice as much grip as the factory stuff did. When I ran my Duster with 1" torsion bars, no frame connectors and 225/60/15's I was still body-rolling and flexing it all over the place. Even with those tires chassis stiffening and torsion bars larger than 1" would have been beneficial.
moparmat2000
Well-Known Member
Hey Blu,
You know you can lead a horse to water, but you cant make him drink it.
I'm out. Some people you just cant reach.
I know what I did was the way to go. Hell any boxed steel welded in as a subframe connector is better than nothing even thin wall steel. If the phoo phooers and naysayers want to debate this they can go ahead and drive their wet noodle handling cars with big tires and super suspensions with flexi flyer bodies.
You know you can lead a horse to water, but you cant make him drink it.
I'm out. Some people you just cant reach.
I know what I did was the way to go. Hell any boxed steel welded in as a subframe connector is better than nothing even thin wall steel. If the phoo phooers and naysayers want to debate this they can go ahead and drive their wet noodle handling cars with big tires and super suspensions with flexi flyer bodies.
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So what happens to all the spot welds in the flexing areas? hmmmm Those flexing areas would have the same "work hardening" problems as well, would they not?
No full frame.... think bean counters and cost. That is another reason they were not full frame. Use the other structures that are required to carry load instead of a full frame. Lighter body means less material.
I've seen NON HP cars have door closing and alignment issues, no broken windshields either. Jack up the right front and see how long it takes to lift the left front... no twisting there. These cars are flex monsters.
Everything is a trade off. Show me a lo-po car that has the spot welds torn out of it from a set of connectors. Connectors make everything a bit more solid.
No full frame.... think bean counters and cost. That is another reason they were not full frame. Use the other structures that are required to carry load instead of a full frame. Lighter body means less material.
I've seen NON HP cars have door closing and alignment issues, no broken windshields either. Jack up the right front and see how long it takes to lift the left front... no twisting there. These cars are flex monsters.
Everything is a trade off. Show me a lo-po car that has the spot welds torn out of it from a set of connectors. Connectors make everything a bit more solid.
Princess Valiant
A.K.A. Rainy Day Auto
I have wondered this about my wagon. It seems more rigid because of the door post and the top.
And why were the early "post" 2 door much more popular among racers.... Yep, that's why... the post created structural rigidity.
Torque boxes are like tits on a boar.... band aid on a cut artery.A cheap, minimally effective, easy to install on the assembly line improvement of the original design. Nothing more. They do the EXACT same thing that a connector does except over a smaller area. They apply load to a greater contact patch.
Even 13-15 second cars can benefit from frame connectors. Just because Mopar didn't do it doesn't discount the benefits of connectors. Drive a car before and after, close the doors before and after (especially if the front rear are on opposing slopes), the cars feel more solid and responsive when driven.
Any potential drawbacks are killed in spades by the benefits. End of story.
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Nice job on installing your frame connectors, looks factory . . .
Exactly!!!
That's what I was talking about earlier too. Yes, you can get fatigue hardening if you make the chassis too stiff. But you can also get work hardening if it's flexing too much. Both can lead to cracks and failures, and the untrained observer won't know the difference between cracks caused by the chassis being too stiff and cracks caused by the chassis being too flexible for the materials it's made out of. That's the problem with Tony's video, he never even considers the increased loads or what that means for increased chassis flex.
And without a finite element analysis based on the loads being applied, no one is going to be able to say with 100% certainty what is right. I know for a fact the factory engineers never considered suspension loads like what I'm putting into my car with my 275/35/18's. Not even close. And I know from my own engineering background that the chassis must be stiffened to handle that load. Have I done the "right" amount of stiffening? Again, even I couldn't say with 100% certainty because I haven't done the structural analysis needed. But I DO know that leaving it stock was not the appropriate answer, even on a car that primarily sees street use. So I'm left with making an educated guess, using torque boxes like the factory did to tie the frame to the rockers. Using subframe connectors to stiffen the body and distribute some of that increased load away from the rockers, so they see loads closer to what was originally intended. Adding a tubular radiator support to tie the ends of the frame rails together, and using forward braces (J-bars) to tie the firewall to the shock towers and the ends of the frame rails, triangulating that entire section. Is that too much? Is it not enough? I can't tell you 100%. I know it was far better than doing nothing, because the increased suspension and torque loads were well above and beyond what the car was originally designed for.
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adriver
Blazing Apostle
An A body is built the same way as a B body.
So stretching the B body car doesn't allow "too much" flex in a B body between the front and rear then?
If a car has frame connectors there is more holding the front and rear together than just the rocker panels.
Would I go to the trouble of adding them to my daily A body?
Probably not just because of down time and work.
But if I've already got them in a B body, I'm leaving them in.
The car is almost 50 years old.
It's flexed enough over the years already.
That's the way I'm going to look at it.
So stretching the B body car doesn't allow "too much" flex in a B body between the front and rear then?
If a car has frame connectors there is more holding the front and rear together than just the rocker panels.
Would I go to the trouble of adding them to my daily A body?
Probably not just because of down time and work.
But if I've already got them in a B body, I'm leaving them in.
The car is almost 50 years old.
It's flexed enough over the years already.
That's the way I'm going to look at it.
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