-Stitch or Seam Welding
So I have done some searching and looking around, and I still can not find any real documentation of where or how FC owners have accomplished this. I have a very vauge understanding of this concept and how to achive it, but I need some alaboration. Any help on this topic would be great being that I am suffering severe chassis flex and groning whenever I put any sort of stress on the body.

 

The procedure generally goes like this: strip the car to a bare shell, remove all sound deadening, remove paint from seams, weld every seem you can get to, repaint and re-assemble.

This is a hardcore race modification, not something to be done over a weekend on a street car. Beware that everything on BOTH sides of the seam needs to be removed or it will catch on fire.

 

Thanks for the feedback. I was actually going to try and do this to a street car on a weekend, but now that you mention it, it would seem more ethical to strip the whole car. But being that I need to stiffin my chassis very soon and shortly (and on a budget mind you) I was thinking about just maybe starting on the door seams just for starters. Lemme know what you guys think.

 

Another option would be to fill the rocker panels with structural foam. Icemark did a writeup on it some time ago. It's much more of a weekend working on a streetcar sort of project.

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/those-think-i-dont-make-mistakes-those-know-better-foaming-frame-329353/

 

what about getting strut tower braces front and rear?

 

The foam thing, in Icemarks words, was more noticeable than front and rear strut braces. So, both would probably be nice.

 

here is a visual for ya, taken from
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/my-project-596765/

 

^^ Remind me never to do that..... what PITA.

 

Waste of time IMO.

If you're going to that extent - even on a track vehicle - you're going to (or should be) be building a cage which is going to make any chassis flex virtually non-exisitent anyways.

Save your mig wire.

 

Even the best cage won't make the car infinitely stiff and it doesn't brace everywhere. Seam welding will help add stiffness in the areas where the cage isn't tied in and will improve stiffness in those areas where it is tied in as well. All the pro teams do it whenever they're allowed to do so. It's not something I'd dissasemble the car to do, but if you're doing a racecar build from scratch then why not?

For suspension tuning you ideally want an infinitely stiff chassis, and this gets you one step closer.

 

I recall seeing this discussed in another forum. Someone mentioned that seam welding adds quite a bit of weight to the car. Does anyone have experience with that?

 

I can see that it'll add some weight, but unless you go totally crazy then it shouldn't be too bad. It'll depend on your technique, if you just add lots of spot welds not so much, if you do stitch welds it'll be more, if you lay a constant bead it'll be even more. But if you do the whole car it'll add maybe 25lbs? 25bs is a lot of welding. Just think of building up a 25lb gym weight with just welding.

 

Yeah I can see it adding some strength, but to me at the point of doing that and adding 40% stiffness with a cage, the 3% from the welding seems nill - but I suppose you're correct.

And I doubt weldign the entire car you would actually burn an entire roll of MIG wire which for me - is a 10lb roll on our welder. Soooo yeah, some, but not very much.

 

I was actually looking at some videos on YouTube, and I found an old video of the RE-Amemiya FC track test. I am now thinking that I kind of want to mimic or copy this simple cage design. Lemme know what you guys think.

http://youtube.com/watch?v=i7gj1x9xhZM

 

https://www.rx7club.com/race-car-tech-103/show-pics-your-cages-please-395960/

Go there, read through the whole thing, lots of good cages.

One glaring mistake they made in the REA car is that the harness bar is WAY too low, that's not safe and wouldn't pass tech.

 

Yeah I was noticing that. Good point.

 

Yep, the harness should be ancorhed so its level with the shoulders of the driver. If its too low, you can crush your spine in a forward impact.