Frame Ties 101

[XfbodyX]

Duke im not questioning your method, im asking questions because of the title of the post "Frame Ties 101" which I take as an educational discussion vs a title of "Frame Ties My Way" So I dont think anyone is questioning what your doing, I thought this was more of a informational conversational type post. I apologize if I am incorrect and wont post further on it.


For many years through the floor was not even hardly considered due to the fact class rules would dictate a roll bar/cage setup at a certain ET level. Other avenues leaned towards the cutting the floor pan but yet so many theories have went unproven on the actual requirements to stop the flex, they just know the flex has stopped.

Here is an interesting article about simple bolt on units in a race car.

Bolt On Subframe Frame Connectors

Some in this article are caged, some or not.

Even though a 4 door car has a longer span is a 4 door car more rigid then a 2 door coupe prior to install? Looking at a stripped 4 door it might seem so but ive never had hands on a 4 door in real life.

 

[Duke5A]

Sorry, reading my previous post it comes off pretty snarky. That wasn't my intention. Please, continue posting.

The whole 101 aspect to the thread title is just to convey a basic method for installing ties.

I've never done a through the floor installation. Just talked to guys in the local car club while they showed my their cars and went over the various modifications and reasons for doing so. The idea is to continue the frame rail running the length of the car like the factory would from a rigidity point. To make it like a factory rail though that conforms to the bottom of the pan would involve a huge amount of labor. Cutting the floor and running the tube through is an easy way to get that floor contact with the least amount of effort.

How much of a difference does this equate in the real world? I don't know. My own experience that I can draw on though is limited to the install that doesn't touch the floor in between and I've never pushed a chassis to its limits like these guys with 10 second cars do. What I do have is I can visibly observe the reduced amount of flex in the body when jacking it up and the increased responsiveness from the suspension.

One of those club guys did show me what his connector and cage combo did though. Jacked the car up, put stands under all four corners and then kicked one of the stands out from under it. Scared the crap out of me, but the car didn't budge and leaning on it didn't do anything. Was very impressed, but this was with a cage though in addition to the through-the-floor ties.

 

[Hayzoos]

The end result is similar to what my 93 Jeep Grand Cherokee had from the factory. It was referred to by some as a uniframe construction. It had U-channel rails spot welded to the floorpan tying the front and back frame sections.

Definitely something I'll add to the wish list.

 

[kkritsilas]

OK, more dumb questions. Thanks for helping answer the previous dumb questions.

When you say through the floor, do you mean into the interior of the floor? Or are you talking about frame ties that go from frame rail to frame rail and are welded to the floor pan on the underiside of the car?

 

[Hayzoos]

Not a dumb question. I'm not sure myself. I thought through the floor did mean cutting slots in the floor pan and welding taller rectangular tubes into the floor pan and to the sub-frame sections for frame ties for nearly a full body on frame stiffness. You may need to engineer in some cross bars to achieve full frame equivalence.

I was under the impression the frame ties featured were to be welded to the floor pan in addition to the sub frame sections. It can be tricky welding sheet metal to stock metal due to the differences in thickness and heat travel. Problems are burning through the sheet metal and/or warping the sheet metal. A decent welder knows how to avoid these issues.

I may be wrong, so I'd like to hear from somebody knowledgeable in the through the floor method as opposed to these frame ties.

 

[80mirada]

Thought the floor means to cut the floor so the ties come up through. For ones that are under floor you would weld any points where they are close enough. The ties keep the bottom of the front structure from moving which eliminates cowl movement.

 

[Aspen500]

I went "through the floor" on mine (30 years ago) mainly just to keep the connectors higher up and make a straight shot front to rear. They don't really intrude all that much inside the car and with the carpet in, you'd never know they're present.

One thing I would do different is make provisions for the parking brake cable to go THROUGH the connector and not over it, if I did it all again.

 

[LSM360]

I'm not the most knowledgeable by any stretch of the imagination, but I think Duke5A has the right idea on all accounts. Going to the track to run 10's? Run it through the floor. Street car, no slicks, etc. His method of tying the frames and not cutting up the car is perfect. You've added rigidity, without excess labor and really going a bit overboard for a street car, and not hacked up your non-race car.

 

[LSM360]

That was an interesting article xfbodyx. As far as them showing, I have dual exhausts from Jegs, the A body 2.5" one, with minor mods to fit M body, and I don't think the ties will hang any lower than the exhaust does, which isn't bad at all!

 

[Milezero]

Awesome information here, thank you all! I'd like to expand the conversation a little. Subframe connectors are something I want to do regardless, just for the integrity of the car. But I have a 79 Lebaron 2 dr with T-Tops. I'm entertaining building a 360 stroker with a beefed 904 trans and swapping to an 8.75 rear axle with 323 gears. Will the subframe connectors offer enough rigidity to handle the build, or do you think I'll need to do something on the roofline the stiffen the top side as well?

 

[M_Body_Coupe]

Awesome information here, thank you all! I'd like to expand the conversation a little. Subframe connectors are something I want to do regardless, just for the integrity of the car. But I have a 79 Lebaron 2 dr with T-Tops. I'm entertaining building a 360 stroker with a beefed 904 trans and swapping to an 8.75 rear axle with 323 gears. Will the subframe connectors offer enough rigidity to handle the build, or do you think I'll need to do something on the roofline the stiffen the top side as well?

Look, if multiple hits at launch from my 4k stall converter haven't caused my frame-ties (DIY sub-frame only welding job, no floor pan intersection like in Aspen500's install) to come apart or other parts of car's body to start developing cracks, I would guess you will be just fine.

Seriously, I would not worry about that kind of stuff unless/until you start building a ProStreet ride where you are sporting massive meats out back with barely enough room for the gear-set pumpking to fit in there! LOL

 

[Milezero]

Look, if multiple hits at launch from my 4k stall converter haven't caused my frame-ties (DIY sub-frame only welding job, no floor pan intersection like in Aspen500's install) to come apart or other parts of car's body to start developing cracks, I would guess you will be just fine.

Seriously, I would not worry about that kind of stuff unless/until you start building a ProStreet ride where you are sporting massive meats out back with barely enough room for the gear-set pumpking to fit in there! LOL

Well, I have no intent on going that crazy! Just don't want to launch the car from a dead stop and wave goodbye to an impossible to replace glass T-Top! I had a 78 Chevy Monza that developed a pretty bad body crease just above the hatchback from the torque, so I'm a little nervous about it.

 

[M_Body_Coupe]

Well, I have no intent on going that crazy! Just don't want to launch the car from a dead stop and wave goodbye to an impossible to replace glass T-Top! I had a 78 Chevy Monza that developed a pretty bad body crease just above the hatchback from the torque, so I'm a little nervous about it.

Yeah, that makese sense, and I can certainly appreciate the worry about the T-tops!

How good are the factory frame-rails in your ride? My coupe had the regular problems, so the front sections where bubbled through. I ended up putting Auto-Rust caps on these, fully welded in. So that certainly added extra strength.

Even so, when jacking the front of the car up I could still see the tell-tale sign of body flex. In comparison, once I installed the frame-ties any visible flex completely went away. To the point that I could lift up the whole side of the car just by putting my jack under the front or rear section and lifting.

Now I have to admit, I went a little ape-shit on these because the Auto-Rust ties had butt ugly ends to them. So I spent a little time making new replacement ends for the REAR section which travelled up the factory frame-rail as it turns up and starts making the wheel arch. Don't get me wrong, I didn't run stuff way up there, but I did put in a section that was about 6" long that capped the factory rail. That required a few tweaks here and there to just pretty it all up and close everything up.

Heck, I still should have these cardboard templates somewhere because that's how I traced the contour of the factory rail first so I could then put that on a nice metal plate and get it cut.

 

[Duke5A]

My father's car is a t-top ride with a stroked 360, 518 and 9.25 with 3.90 gears. Has frame ties that don't go through the floor and it's just fine. Suspension is beefed too with heavy springs/bars. You'll be just fine with only the ties.

 

[Aspen500]

Regardless if the car is modified or not, connecting the front and rear subframe rails makes a noticeable difference in the feeling of the car, in ride, handling and noise (such as squeaks and rattles). The whole car just feels more solid.

 

[Oldiron440]

The truth is that unless your car is making 500 + hp and torque and dead hooking a 4500 rpm launches at a dragstrip you probably don't need them. But like 500 says they will make the vehicle feel better when driving it. It's not how much power you have it's how much your hooking, this includes road course with sticky tires. If your goal is long smoking burnouts on the street there not needed.
I ran my Volare into the mid 11s with out them pulling the front wheels every pass. I did start noticing movements in the unibody at that point, so I installed the frame connectors and cage at the same time.

 

[Bill Park]

I have frame ties in my 79 Roadrunner . It has a mild 440 in it and I do use it and I have been at a dragstrip. I also had them in my 10 second 68 dart. The difference that it makes to the solid feel of the car is beyond huge . I would never go without them