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GTM Coupe Special
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Author:  dodo_z [ Sat Jun 21, 2014 3:48 pm ]
Post subject:  GTM Coupe Special
Everything startet with a 1985 GTM Coupe without engine.
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The car had to be converted to left hand drive and needed more than just a new engine. The interior was in a bad state, exept the seats. It was equipped with sunroof and a bit or rust at the sills.

I startet with the roof and thought a slightly more curved roof would suit the GTM. Therefor I used a mould I had made a long time ago, using the rear half of a Mini roof panel. After laminating the roof segment I had to cut it into two parts and fixed it with some glue. At a later stage I will have to glass it in correctly.
After the roof I started modifying the rear end to accept Ford Cortina MK-I rear lights.
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On the last picture you can see the BF-Torino "Silverstone" seat I will like to use and a first attempt for positioning the steering.
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dietmar
Author:  West [ Sat Jun 21, 2014 5:21 pm ]
Post subject:  Re: GTM Coupe Special
Welcome to the forum, I see we have GTM in Germany now! interesting mod making the roof more curved.

Neil
Author:  dodo_z [ Sat Jun 21, 2014 7:25 pm ]
Post subject:  Re: GTM Coupe Special
There is at least one GTM Coupe road registered in Germany:

Image

There is also a Rossa MK-I Road registered.
Author:  West [ Sat Jun 21, 2014 8:55 pm ]
Post subject:  Re: GTM Coupe Special
I had forgotten about that one I knew it was in Europe somewhere.

Neil
Author:  Midas [ Sat Jun 21, 2014 10:05 pm ]
Post subject:  Re: GTM Coupe Special
That roof looks perfect, the standard flat roof has always looked odd to me.
Author:  dodo_z [ Mon Jun 23, 2014 12:18 pm ]
Post subject:  Re: GTM Coupe Special
I didn't like the use of the Mini bumper, so I tried to use a Lotus Elan front bumper. After fitting the mid section of the Elan bumper and bending the bonnet to fit properly, I thought why not using the front skirt of the elan, too. It still needs a lot of work, but I like it.
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The steering is in position, and the pedal box is getting modified to suit this special usage. You can also see a very early design stage of what my dashboard should look like.
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Author:  dodo_z [ Fri Feb 03, 2017 8:57 pm ]
Post subject:  Re: GTM Coupe Special
After some other work, I recently started working on my Coupe again.

At some point I decided to try something completely new. Making a lightweight chassis using honeycomb and carbon fiber. To be honest I have never build a chassis for a car, but making a more lightweight and stiffer one compared to the original chassis shouldn't be that difficult.
That's one reason why I called it Special, there are some more special things to come.

I also had some thoughts about the engine...

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File comment: Carbon/Honeycomb front bulkhead
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File comment: trial fitting the first panels
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File comment: some minor changes to the front subframe
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File comment: Carbon fiber window frame and glass reinforcement for the door skin. Changed to Mini door lock.
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File comment: altering and reinforcing the door cards
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Author:  West [ Fri Feb 03, 2017 9:04 pm ]
Post subject:  Re: GTM Coupe Special
:mrgreen: :mrgreen: :mrgreen: :mrgreen:

I am Jealous

I have been wanting to do a Honeycomb chassis for ages, I was looking at doing an aluminium version. I have it roughly drawn out!

Looks good. Be interesting to see how the elan front turns out.

Neil
Author:  techead [ Fri Feb 03, 2017 9:33 pm ]
Post subject:  Re: GTM Coupe Special
Love the look and idea of the honeycomb chassis. Your other ideas are also looking like modernising a great we car.
I am looking at doing something similar with a K3, see the post in the K3 section, and would love more details on how you did yours.
How light did it end up?
How stiff do you recon it is compared to the steel?
I am planning on replacing the front and rear sub frames with separate box sub frames, I recon I can loose a substantial amount of weight.
Author:  dodo_z [ Fri Feb 03, 2017 9:58 pm ]
Post subject:  Re: GTM Coupe Special
techead wrote:
Love the look and idea of the honeycomb chassis. Your other ideas are also looking like modernising a great we car.

Well in the end you won't be able to tell if the car has a steel or carbon fiber chassis, as it will be painted completely. Here in Germany we have the so called "H" number plates, which are for historic cars (that are in a good and original state).
So everything I change has to be more ore less invisible or period style tuning including the frontend, rear lights, dashboard, engine, wheels, ...

Quote:
How light did it end up?

My main goal is to prove that it can be done and getting experience for doing the same thing for other car projects. I think it will be less than 30Kg, but at least 3 times stiffer than the steel one.

Quote:
I am planning on replacing the front and rear sub frames with separate box sub frames, I recon I can loose a substantial amount of weight.

Why not using the titanium ones made by Carl Austin (Force-Racing)? I would love to use them but I can't as they are not period style.
Author:  flapjck1 [ Fri Feb 03, 2017 10:22 pm ]
Post subject:  Re: GTM Coupe Special
Yuppie, next LHD coupe :)
Author:  dodo_z [ Fri Feb 03, 2017 10:36 pm ]
Post subject:  Re: GTM Coupe Special
There was another mod I did. I did't like the look of the headlamp rim, so I completely redesigned the Headlamp area to use standard 7" Mini headlamp rims. I'll post a picture soon.
Author:  techead [ Sat Feb 04, 2017 10:47 am ]
Post subject:  Re: GTM Coupe Special
Force racing sub-fame looks amazing, but way to expensive for the car. I would need 2.
I am also looking at possible changes to drive and suspension as well and they may force compromises to be made.
Going back to your carbon honeycomb. Did you buy the sheets pre-made then join them to make the floor and bulk heads or did you lay them up yourself?
I can get my design to be almost flat panelled and a pre-made sheet would speed up the production. What spec of materials did you use? I am at present designing a mould and thinking of using grp honeycomb and other high tech materials to make the suspension tubs as I like to call them.
Author:  dodo_z [ Sat Feb 04, 2017 4:20 pm ]
Post subject:  Re: GTM Coupe Special
If I try to sum up the material and time I need to make the chassis, the Force Racing parts are quite cheap.

All sheets are made by myself with different layup and honeycomb thickness. The next parts I'm going to make need moulds to be made. So it's even getting more expensive.

All Carbon sheets are made using vakuum infusion to get the best quality possible.
Author:  dodo_z [ Sat Jul 15, 2017 7:11 pm ]
Post subject:  Re: GTM Coupe Special
Finally I managed to make the mould for the sills. I took some pictures while making the first of my carbon fibre honeycomb sills.

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The outer carbon fibre structure which was made using vacuum infusion.

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Preparing the honeycomb.

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Glueing in the honeycomb using vakuum.

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The honeycomb is in its desired place, now it's time to prepare the inner carbon layup.

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Everything is done, now the resin will cure under vacuum pressure. Tomorrow the first sill is ready to be trial fit to the other chassis parts. I'm curious about the weight.

I also did some measurements where to put the seats, gear lever and handbrake to make the reinforcements needed. Getting the desired stainless steel tube (35x1mm) for the water rail inside the tunnel isn't that easy.
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