Chassis Bracing

[turboedsloth]

Hi all,

I am currently building up a 32 4 door to do some motokhana, hill sprints and general track racing work. Am looking at getting a 4 point cage put in it, but am just curious as to whether i will need any other bracing for the underbody at all. I have been looking at http://www.ultraracingaustralia.com/page18.htm this gear but am unsure if it will be benfical at the end of the day.

Cheers

[badhairdave]

There's a lot of useless bracing out there.

The ones worth looking at in my opinion:

Caster rod brace (similar to the nismo ones) as there is a small inward force (maybe around 10-15% depending on angle of the caster rod) applied to the bracket under load so this brace actually does something! Not triangulated so no resistance to twisting

Front and rear strut braces, same deal, the struts aren't vertical so you are preventing them pushing inwards, unfortunately they are not triangulated so no resistance to twisting and the bulk of the force from the struts is vertical, so twisting.

The A pillar brace triangulates the front strut top to the base of the a pillar. It's a good thing, but consider that that part of the chassis is built like a brick shit house so how effective can it really be?

Everything else, under floor bracing in particular, is all in the same plane. In the middle of the chassis you are mainly looking at twisting forces and a ladder brace has bugger all resistance. Some of the cross braces for hatchbacks can be effective. B pillar brace, don't get me started...

Your cage, if it has a cross brace on the main hoop and a bar between the rear legs at the back, will do more to increase chassis rigidity than any bolt on bracing.

[Beer Baron]

yeah agreed. all those little bolt on brackets that various companies make mostly do bugger all but add weight and restrict access to various bits. castor rod brace as above is good (i run one), strut braces (even better if you have one that triangulates to the firewall), but as above the cage will help stiffen things up a lot. forget the mickey mouse under floor bits.

[BOZ22N]

In my R33 gtst I just ran the gtr strut braces and it was not too bad but you could hear and feel the car twist. Since then I have had a full roll cage welded in with a cross in both the main hoop and rear legs and the car feels sooooooo much better I love it. I would just stick with a good cage and some strut braces. I have been looking into the caster rod brace for a while now and am yet to find a good one I like. Good luck.