I think Chris has already replied to this question but, just to save his time, it is not a roll cage as is required for racing but just stiffening for the roof panel. The Z3 already has rollover protection behind the seats (if they are fitted).

Thanks for the answer 275, but what I really want to know is, is it essential to fit the cage to support the roof panel or could you build a car without it?

Mr T. I think if you don't use the cage the joint of the roofpanel/windscreensurround will crack or at least move/flex a bit as the stock body is a convertible.
As i remember well you have a slk convertable is'nt it?
If you tie a piece of string between the windscreentop and the rear of the car very tight and drive one wheel on a high curb you can see the string hang down a bit,just try..........
Usually the roof structure is the strongest part of a unibody car.
The cage Chris has made will stiffen up the body a lot and stop it flexing.
René

Towed, Rene and 275 are correct, the GRP roof section would come under a lot of stresses if some sort of bracing is not fitted. If you don't want to fit the supplied "cage" maybe forming a close fitting framework of 25mm steel box section glassed to the inside of the roof linking into windscreen frame, behind door shuts and down the rear pillars to the Z3 boot structure might do the job. This is a MAYBE, I know from production MX250's and the SWB prototype that the cage system works, a smaller section frame may not have the same torsional strength.

Rene is spot on with the curb/string comment, I am currently driving a targa roofed Mk2 MR2 and park on the pavement outside my house overnight, on frosty mornings you can hear the roof panel joints crack as you drive off the curb. The BMW Z3 is very rigid structurally for a convertible but they do still flex.

Thanks for the replies, I guess I'll just go for the roll cage/brace then. :)

Not sure where you got the idea that I drive an SLK Rene, I actually have a Nissan Micra. Oh, and this -

http://i1301.photobucket.com/albums/...psd3163218.jpg

http://i1301.photobucket.com/albums/...psc62a9dac.jpg

http://i1301.photobucket.com/albums/...psa26d49bb.jpg

http://i1301.photobucket.com/albums/...psfe20db4f.jpg

[QUOTE=Mister Towed;63727]Thanks for the replies, I guess I'll just go for the roll cage/brace then. :)

Not sure where you got the idea that I drive an SLK Rene, I actually have a Nissan Micra. Oh, and this -

Sorry,i must have you mixed up with another guy..........WCA perhaps?
The silver car looks good,is this a new build?.............i can't remember seeing any pictures of it before..........:violin::eusa_boohoo:
Forgive me as i am new here..........and a bloody foreigner too:icon_frown:

[QUOTE=reneanglia;63731]Not a new build Rene, it took me two years to build and I've had it on the road since summer 2013.

If you go to the Ribble and Sammio thread, then click the 'views' tab on the right hand side of the page, my original build thread should pop up. I also have an 'on the road' thread which covers my experiences with the car since finishing it.

The SWB won't be replacing my Spyder: earlier this evening I told my wife that I was thinking of selling it to fund a new project but she's put her foot down, forbidden me from selling it and instructed me to build a 250 to go next to it in the garage. Result. :)

If you hadn't seen my car before then you won't have seen the three West Norfolk Spyders together -

http://i1301.photobucket.com/albums/...ps29222155.jpg

http://i1301.photobucket.com/albums/...ps81409e13.jpg

http://i1301.photobucket.com/albums/...ps311af8e0.jpg

Good luck with your SWB project, and don't worry about the foreigner thing, we're all foreigners somewhere.

SLK is mine - correct. It does have flex with the roof down but a bit less than the Z3. Either would need bracing if you fitted a glass fibre roof though.

So how does the factory fitted hard top cope?

On the Merc it isn't too bad as it is integrated into the car but there is still creaks and squeaks at the back when 'pressing on'

On the BMW I have only driven with the canvas roof

Almost full set of panels hung on your workshop jig Z3. Inner structures of boot. bonnet and front end section to follow shortly:

http://i1046.photobucket.com/albums/...psahztii1t.jpg

http://i1046.photobucket.com/albums/...pspuk5lsat.jpg

This is the Z3 windscreen surround minus is rubber infill trim.......

http://i1046.photobucket.com/albums/...psmzidkjrc.jpg

.......and with the kit roof in place. A false period windscreen rubber with chrome insert can be stuck to the windscreen to reduce the glass area further.

http://i1046.photobucket.com/albums/...ps28oslxju.jpg

Replacement sill covers bolt on using the standard Z3 fixings:

http://i1046.photobucket.com/albums/...psqtufio6a.jpg

Kit door skins have return edge which allows them to be bonded over the existing Z3 doors once glass and trim have been removed and an area in the centre of the door skin "pushed" in:

http://i1046.photobucket.com/albums/...psn61fyfp6.jpg

http://i1046.photobucket.com/albums/...psjqi9y8yf.jpg

http://i1046.photobucket.com/albums/...psr0avasym.jpg

New side window installation and door handle mods would normally be completed before GRP skins are installed.

That looks so much more professional and finished the the MX250 kit. The finish looks to be very good, well done that man!
As you are putting this one together it might be an idea to take as many photos as possible and highlight the build process.
You could then E-mail the build manual to anyone who enquires about a kit.

Thanks.

When the kit is installed on Geoff's car we will be producing a build manual.

Is the rubber infill piece on the stock z3 needed to keep the water out?....or is the glass itself bonded in the frame?
René

Chris - Given how good this looks now (if you ignore the flash lines), I can imagine it will look fantastic painted. :cool:

The way it all fits to / around various points on the original BMW is very clever too.

Good luck, Paul. :)

Looking good guys.
Nice detail work and the inner panels should really make for a well finished result.

See you soon.

Cheers, Bob.

The Z3 windscreen is bonded, the rubber trim is just a decorative cover.

Thanks Paul. The development has been a huge amount of work, but well worth it in the end.

Wow! Just wow.

+1

Just trying to work out finances. as I said, been a long time since a kit got me this interested. brilliant.