Help with unibody modification...

[gpchris]

I need to cut into the unibody for added clearance.. I need to cut about this much out here:



I will be cutting the lower 90* bend.

I want to make sure it doesnt bent out of shape while cut. Im going to weld a couple days after the cut. I know the car cant be on the ground because the springs will push up on the unibody. Im thinking about putting it on stands that will be placed on the subframe. The subframe should hold it together as long as the strut towers dont have any pressure.

Im probably just being paranoid but I DO NOT want to screw this up.

Any advice?

[gpchris]

Come on guys.. Any suggestions? I already thought to put the strut bar on for added support. I may be cutting tomorrow so HELP ME!!

[3100 MPFI]

I am not a big fan of cutting anything structural on these cars, but I would imagine that if you support the car, and then reweld a new plate in there, it will be fine. Just remember that the new welds will need to be STRONGER so that there is no risk of flexing.

[gpchris]

I am not a big fan of cutting anything structural on these cars, but I would imagine that if you support the car, and then reweld a new plate in there, it will be fine. Just remember that the new welds will need to be STRONGER so that there is no risk of flexing.

Thanks for the reply.. I would not be cutting the unibody if i didnt have to but It must be done for my project. Im not at all worried about my fabrication. Im worried about the unibody bending or warping while its cut open.

This is how I plan on doing it:
Install STB
Tighten interior tiebar
Reinstall factory cross braces
Jack the car up by the subframe
Remove both front wheels (less weight pulling down on the strut tower)
Cut

If you or anybody else has any further tips or advice please let me know. I dont want to screw it up but it has to be done.

[3100 MPFI]

I would think that with the subframe installed, and the top bar in place it would be fine. As an added precaution, I would probably try to level that complete side of the car (both the front and rear off the ground), but then I would put 2 jackstands on the front of the car near the front of the bumper, and near the rear of the subframe to help support the car.

I honestly think that as long as the subframe and strut brace are in it will be fine, but I understand about wanting added precaution.

The only thing I can think of (seeing that I have never done this) is jack up the entire side of the car so it remains level, and you don't have added stress on the body from just 1 CORNER being up. To me, 1 corner being up would have more stress on just that 1 side. I think having the SIDE jacked up instead of just the FRONT will keep from added stress to the front of the car.

You are cutting the SIDE of the car, and not the FRONT, so it seems to me you want the SIDE to be level.

does that make sense?

[gpchris]

Makes sense but Im cutting in between the subframe mounts. So the subframe should hold it together. However when jacked up that could cause extra flex.. Maybe if I put blocks under the main rails after the subframe. Not holding it up but putting a little pressure. Im probably being way too over paranoid but Im willing to take all precautions necessary.



So you think thats the way to go? jacks on subframe and blocks on the rails midcar?

[Alxsmt]

just fyi.. for when you repair a damaged car, you CAN NOT just weld a pannel in, the weld has to be in the same spot and the same size weld as the factory. the factory has the welds where they are and the size they are for crashes and absorbing the impact. if a car is repaired incorrectly and some1 get killed over it, you responsable. thats how serious they take this stuff for just repairing a damaged car and you want to cut it, change the crush zones and redesign the cars construction after designers spent millions of dollars to make it safe

http://www.youtube.com/watch?v=bpuHTZlbVAc

i have 2 years of schooling on automotive refinishing/collision repair... do some research on the subject before you do it, it may change your mind. its amazing what little changed can affect your cars saftey

what exactly are you cutting your car to make room for?

[gpchris]

I understand that but I have a hard time believing this small modification is going to make much of a difference. Yes it will slightly alter how the frame crushes in an accident but it will not lessen the safety of the car.

If you look at the video theres a large section of the frame that was reweled. Also the weld is rusting and they used body filler on the frame itself. Its obvious the guy who repaired it was lazy and still it was only pushed in 3 inches in the cabin.



Anywho I cant cut it today because its raining and I need to do this on my driveway..

[gpchris]

I have it all ready to cut.. Im scared




I ended up putting stands under the subframe and the pinch rails. The back wheels are still on the ground but the suspension is somewhat loose. I think im good to cut.





Ok Ill post in a lil bit when its cut.

[gpchris]

Ok I was being very paranoid. Theres no way my frames gona bend. Heres the photos







I obviously still have to grind it smooth

[gpchris]

Ok heres what I have so far





Still have a little grinding to do as well as cut out metal for those rectangular holes.

Again I DO NOT wana screw this up, any advice or constructive criticism would be appreciated.

[gpchris]

All done.

[3100 MPFI]

looks good

[vorvon22]

looks good to me. all openings into the rail are sealed and painted. I cannot see the welds but as long as they are good then you have no worries.

[gpchris]

Thanks guys

vorvon22, the welds were grinded down. My welder has 55 years of welding experience. Hes built full custom frames and everything, Im very confident that it will hold up no problem.