Best way of stiffening up the chassis?

[24OZ]

Hi guys,

looking to ideas for stiffening up the body/chassis on my Z,i've noticed that there are stress points above the 1/4 windows in the section between the hatch,i beleive this can be caused through age as well as "abuse" :roll:

i spoke to a guy recently who builds roll cages,he said that a 1/2 cage would help but not much(more for safety &/or CAMS purposes),that i really needed a full weld in cage(not bolt in front half)which is not road registerable in WA unless it's on a concessionary lic(mines a daily driver)

has anyone stiffened up the frame rails,added a cage,added strut braces,made a ladder frame,made a torquetube,braced the shock towers to the firewall ,etc,etc......looking for feedback on how much it helped

anyone consulted an engineer in this department?

cheers

paul

[PZG302]

Paul,

 

There is plenty you can do to stiffen a car up, but most of it is only of benefit on the track and will cost a fair bit to do properly.

 

The other down side is that in stiffeneing the car up in one area you may put more stress in other areas and cause more long term damage.

 

Personally my 240 which is a pure track car has had the following done to it:

:arrow: Seam welded chassis rails and inner guards as well as shock towers plus firewall and anything else under the bonnet that was not bolted in :lol:

:arrow: Mixture of nolathane and rubber bushes for the suspension, you do need some give for the suspension to work properly.

:arrow: Removable strut brace, only removed when access to motor is needed, eg remove, or to get rocker cover or head off.

:arrow: Full roll cage welded in, including tags to tie the a pillars to the cage. Cage also incorporates rear strut brace with the rear legs from the main hoop finishing on the strut towers and a brace across the car welded to these legs. This brace is also used for the harness shoulder pads for safety, as the angle is spot on.

:arrow: Rear suspension bushes are agian a mixture of nolathane and rubber.

 

We do see areas of the body that fatigue quicker than would be expected as forces are moved to areas where they normally wouldn't act, and then we have to look at how we can strengthen those areas of the body.

 

The car would be unlivable on the street with the set up, plus the 420-450lb springs and the locked diff.

 

We have also stripped pretty much what we can in regards weight out of the car, though the next step would be to replace the hatch with a fibreglass one and redo the wiring to save a couple of kilos hear and there. I run metal guards that are lighter than fibreglass, but you don't want to lean on them :lol: .

 

The car comes in at a race weight of 980kg with 2/3 tank of fuel ready to hit the track. I believe there maybe another 20kg we cab get out, but too much more then I believe we would be sacrificing structural integrity and safety in the car.

[620Z]

Pual I too welded a cage into my care and it made a big difference to it's andling even on the road. Mine is an 8 point cage but you could get away with a 6 point cage and just not put in the "Cross's over the doors so that it is still legal. Not the best scenario but would go a long way to fixing your problem. then you have the option to later weld in the "Cross's into the door sections later if you wanted to.

I have the Cross's on my doors and it is road registered. Probably not if I go pinned for a road worthy. But Lifes full of risks and I have been pulled over in the car a few times but the cops haven't said anything, yet! Anyway ther are a few shots of it on this site I think. If not let me know and I can send some. But anything short of a welded in cage is just a band aid. But it depends on cash, how serious you are about getting your car right and how concerned you are about safety. Good luck.

[Scando]

Before I put a cage in mine it used to lift the inside front wheel up to 20cm on the ground on some corners on the race track. It also used to lift one front wheel an inch or two on hard launches. Now it sits perfectly flat and I picked up over a second around our local race track. So they work VERY well, it just sucks about your registration issue. You can get away with just about anything here in tassie if you get an engineers certificate

[620Z]

Yeah I also noticed a difference in the cars driving on the road. It didn't wonder as much since the body didn't flex anymore. Minor because it was a combination of about 3 things but that certainly was one of them.