Frame building, where to start?

[driveit]

I know nothing about this other than the fact that my car is very heavy at nearly 4000 lbs. It seems to have a lot of flex in the corners and the frame hangs down low so that you can see it below the side of the body. This is my daily driver and will be autocrossed down the road if possible. This may be in the wrong section, if so just let me know.

My plan is to lighten the car as much as possible, to make it more rigid and more fuel efficient:

Light weight frame.
Stronger than factory.
Increased ground clearance.

Where do I start? What material? I am assuming 2x4 steel boxed tubing. Would this be lighter?

[raustinss]

Please don't take this wrong, it might be best time buy one already fabricated for you. Reasons are they (manufacturer) will have everything. Engineered for you. Thus making it easier for yourself with piece of mind knowing that yours and possibly your families lives are safe

[astroracer]

With no knowledge in frame design, fab experience or the tools to do the job, this is a HUGE undertaking.
Lighter and stronger are usually oximorons when it comes to frame design. Making it stronger usually means making it heavier with added tubes and material for roll cages and chassis stiffeners. If I were you I would do some serious research into the design side and also think about the cost and time involved. Materials, tools, shop space and the time to build a complete chassis (that works) let alone the knowledge to correctly use the tools you need to have are the major show stoppers here.
After all is said and done, taking Ryan's advice to look into an aftermarket frame may be the most time and cost effective way for you to tackle this project.
Of course there are other ways to look at this. Adding solid body mounts and rebuilding the suspensions with performance components is a step in the right direction. These are fairly easy to do and will tighten up the car. For street driving this may be all you need. Poly bushings, good shocks and a set of big sway bars will make a huge improvement that will surprise you.
If you want some insight on what it takes to design and build a frame from scratch, look through my BadAst build thread. Lots of info in there, from concept and design to the actual building of the frame and suspensions.
Mark

[driveit]

Thanks to both of you for the reply. I do want the car to be very safe. My main goal for the car is to be driven. I want it to be a sporty daily driver. I am not worried about being the fastest guy at the track, however it would be awesome to claim those bragging rights. It sounds to me that it would be best to Upgrade my suspension as planned then move on to lightening other areas where possible.

Here is my setup as of right now.

355 ci. around 350hp or so maybe a few more with the headers and such.
273 rear gear and Jegs 450hp rated 350 turbo and custom ProTorq Stall Converter.

Everything replaced under front end excluding what needed to be pressed out or pressed in. All HD factory replacement parts.

New Idler arm
New Inner/Outter tie rod ends
New Centerlink
Belltec HD front springs stock height
Gabriel Ultra HD shocks.
CPP 74 Camaro 2" drop spindle.
New Cardone Stock replacement caliper.
New rubber lines.
Assuming original rotors, steering box, rag joint.
Stock sway bay.

In rear everything is stock excluding:
Belltec 1" lowering springs.
Gabriel Ultra HD shocks.
No sway bar.

Don't get me wrong it handles 10 times better than it used to, but its not where I want it to be. The plan for the future as money and time allows:
Get a rear sway bar
Upgrade to coil overs on all four corners.
Do a disc conversion on the rear.
Upgrade to drilled and slotted rotors on all four corners.
Get adjustable upper and boxed rear lower control arms.
Get wide 18" tires and wheels with a lower profile tire for less tire roll in the corners.

I think I will be much happier when I get to this point. I have also been corresponding with Ron Sutton who is a member here about this same issue. I have taken some information from the thread he has. His thread was greared more toward traction, downforce and shaving time. I have kind of re-purposed it and turned it around for fuel savings and making the car more aerodynamic. I am thinking of doing a full lightweight belly pan. Adding an adjustable front splitter, rear diffuser and nascar style adjustable rear spoiler. All of this in the name of fuel economy. I am planning all of this out now and learning as much as I can. My budget is null currently so learning and sourcing parts as well as those people that I will need for help when the time comes is now.

Mark, I will definitely be checking out your build thread. I want to learn as much as I can even if I decide to stay where I am with the stock chassis. Any other tips or suggestions are always welcome. God bless!

[driveit]

Mark, Wow. You absolutely amaze me with your skills... I just went over your thread and found out that there if definitely a lot more to it than I thought.

[driveit]

Well it looks like after doing some research and talking with a few of the experts on here I will not be doing the custom chassis. At least not for weight savings and not in the near future. My skills or my budget will not allow it. But I have gained a lot of knowledge on the subject and will continue to learn more. The plan for now is to still with the stock frame and strengthen it. I will be adding some aerodynamic components to it which will hopefully help me on quest for 25+ mpg 4000lb daily driven muscle car. For now I guess this is the end of this thread and I will continue posting related info in my build thread.

https://www.pro-touring.com/threads/108244-Prject-quot-Vision-quot-74-Chevelle-Build