unibody question?

hey max ur info is great i appreciate everything uve helped people with...my question is about putting an axel and back half on a unibody car...do i just weld the rails coming off the front of the notch to the unibody floor? because that is what it looks like but that doesnt seem like it would be strong enough?also how would i go about scouting out the right straight axel for a car? just measure from hub to hub, find one close,and extend or shorten it?thanks man

Uni-body cars are tricky. Where to mount the rear frame section and how to hang the rearend is going to be very different from car to car. Plus it would probaply be a good idea to tie the frame into the body at several key points, where these key points are is tought to say. If you could post a pic of the car with the rear area cut out I can give you my best oppinion.

And with the straight axle, you can build one or buy one. Again it totaly depends on the car and how you are planning to set it all up.

thanks...got another one for u..that is my othe option..a cantilever rear set up..what is the best advice for a starting point...i know thats very vague..but i just dont know how to get started.i mean designing/sketching is a good start, but what if any is the simpliest way of achieving this? without making it crazy over the top?

Figure out the leverage ratio you want, and or how much lift you want are good places to start..then draw it up and I always build a quick mock up to make sure that it works the way it is intended...

Here is one I did, and it works great, gets good lift and has the shock and bag all integrated into one arm, Oh and the shock is hidden under the bag so you never see it.

how do u figure out the leverage ratio? and do only true cantilevers with IRS give good NC? so there is no sense in using a straight axle if i intend to do the cantilever mount...work looks good...sick fab work BTW THE WORK IS GOING TO BE DONE ON AN 01 VW GTI. thanks for th pic

Hmmm... That sounds like "What end of the sword to I hold on to?"

This might be a bit over your head right now if you don't know how to calculate leverage ratios. That is the easy part compare to what else is involved. Take no offense, but I think that you should do a LOT more home work before diving into this one. I do understand that is why you started this thread, but you are missing some imoprtant steps before you even get to the point of asking how to do it. Dig up an old highschool geometry book and take a refresher look at it. Once leverage ratios start making sense, a lot more of this will become clear.

none taken.im humble.thanks

here is a point I'd like to make...a unibody car has the same principal in the structure as a regular truck frame. if you look at the bottom of a unibody or cut one in half (i have alot) you'll see a unibody is just a bunch of SHEET METAL bent and folded and tack welded and glued in a manner that closely resembles the frame rails and crossmembers of a truck frame. When creating a transition (step notch for a straight axle) I would remove as little as possible of the existing unibody rails and what parts you do remove brace the crap out of it like max said. I suggest you jack up the car and like max said start finding points that look like they are integral part of the chassis and use those as your transition points where your notch and bracing will go. I think even the floor pan and other thin sheet metal areas of the bottom of the car are necessary to the structure hence the funny contours rather than perfectly flat floors.............
hope this made sense and helped you in anyway