Sounds interesting! Just remember if there is a feature there on the chassis then an engineer has designed it for a purpose. Out of interest what are you building this for? track days, racing, hills?

Dave.

it needs to be road legal and safe to drive on road.   Ive had a stripped and caged car before and a heated windscreen isnt good enough really as the rest of the car steams up and everything drips with water. A small heater box is worth the extra weight for a touch of practicality. Its staying cosworth YB turbo.

Neil i reckoned without considerable bracing, thin carbon panels and roof like that would be too flexible.

i have had thoughts along the lines of what your thinking, mine were to to mould the complete side panel (with door removed) then replace the whole side. mould the roof skin. then the hang on panels. big project though, i'm only doing a pair of wings and a bumper and the moulds do take up space...

IS it track only Warren? If so a front heated screen (might already have one, as some fords do) would be a better option over having the standard matrix in which weights a ton, also if track only carbon light blanks could be an idea, unless regs say the car must have working lights. i love the idea of this project! what engine are you going to be running?

you want it like like this?

http://passionford.com/forum/restorations-rebuilds-and-projects/213573-ag-motorsport-carbon-focus-cosworth-800-bhp-new-season-2011-a.html

Is that a Puma Warren? Some of the things to think about, cutting the rear flloor plan ( where the spare wheel and such goes) as this sometimes is the lowest point on the car, and replacing with flat metal sheet and a tubular brace underside to increase rigidity abit more. Also as your putting the cage in i am assuming you are going to do a full seam weld too? Just the seam weld alone can give massive rigidity benefits, i was reading a thread about a crx that was so rigid he used to crack windscreens 

Hopefully next year i will be stripping out my car and fitting a weld in cage as part of a weight loss programme.

once the cage is in, i want to get drastic on cutting out metal and saving weight on the non-structural elements of the shell.

Obviously i will replace as many cosmetic body panels with carbon ones - plenty to save there.

However my slightly insane plans include replacing some of the now redundant monococque. 

In a handling sense, the roll cage will be far stiffer than the original bodywork, so ive nothing to loose there.  In a safety sense, the roll cage alone is strong enough as defined by FIA/MSA standards.

So all the bodywork needs to do is keep the weather out. 

In an ideal world, i would cut off all the metal work above the suspension top mounts and secure the cosmetic panels to the cage. However you still need a form of support framework for the panels, roof and boot to stop the carbon panels flexing too much.

So what i intend to do is cut out the steel framework within the upper part of the car and remould it in carbon kevlar. A major panel is the quarter framework spanning the B and C pillars and roof line.

from the inside:


Outside:


As you can see it is a double skinned inner frame. It is made of approx 1mm thick pressed steel.

Relatively easy shape to mould and i reckon considerable weight savings to be had over steel.  Some of my mates reckon the car would crumble, but im not convinced. The suspension points are all tied into the roll cage so the basic floor pan monococque has a steel frame supporting it of the roll cage which is significantly stiffer than oem pressed steel so IMO no structural weakness compared to a standard car if those inner panels are replaced. 

Plus of course a carbon/kevlar replacement will be stiff in itself in handling terms. Sure in heavy roll over type crashes it fails differently and more catastrophicly compared to pressed steel, but thats what the roll cage is for.

I intend to do the same to the roof rails above boot lid and each door as well as the roof central brace. I intend to leave the A pillar and windscreen bracing in steel as welded to the cage they will be useful for extra strength.

If i can get extra spaceframing tubing welded in along the sills and gearbox tunnel and across the floors, i may even cut out the steel floorpans each side of the car and replace with carbon kevlar too.

Possible or just plain insanity?? Some of my firends just think im insane.