GTD chassis mods

[Simon]

As I have posted before, I'm tearing down my GTD to start the build again from scratch. I'm keen on Mick's rear chassis mod (Southern GT), and I'd like to put a bit more strength in the sill area, but is there anything I can do while the chassis is bare to improve the basics?
Any advice appreciated.
Thanks

Simon

ps, I'm keen to avoid the (alleged) harshness of rose jointed suspension for what will primarily be a road car, so will stick with poly bushes.

 

[Brett James-McCall]

Simon,
See the beginning of my build thread, I have more photos at home.

Brett

 

[David Morton]

Hi Simon,
I put in 3 extra braces between the outer and inner upper sill rails so firstly that the sill could accept being stood on (when I first went to Poole to look at and ride in a car Simon [Osborne?] told me not to stand on the sill as I got in the car) and secondly to brace the outer rail from side impact as that is all there is protecting the fuel tank. Additionaly the lower sill area near the front of the fuel tank below the A post had (2?) extra diagonal bracing installed as part of the roll bar installation to form a 'front circle'. If you like to visualise it the roll bar is two complete circles - one in front and one behind the seats with a cruciform connecting the two above inside the roof and the sills connecting the two from below.
I think the right sill will be coming off the car shortly and I'll attempt to get some photos from underneath when it does.
Dave M

 

[Ian K]

Hi Simon,
I put in 3 extra braces between the outer and inner upper sill rails so firstly that the sill could accept being stood on (when I first went to Poole to look at and ride in a car Simon [Osborne?] told me not to stand on the sill as I got in the car) and secondly to brace the outer rail from side impact as that is all there is protecting the fuel tank. Additionaly the lower sill area near the front of the fuel tank below the A post had (2?) extra diagonal bracing installed as part of the roll bar installation to form a 'front circle'. If you like to visualise it the roll bar is two complete circles - one in front and one behind the seats with a cruciform connecting the two above inside the roof and the sills connecting the two from below.
I think the right sill will be coming off the car shortly and I'll attempt to get some photos from underneath when it does.
Dave M

Dave,

I would be interested in seeing some pics when you get a chance. I have
been thinking the same thing WRT the sills and extra bracing. I also wonder
about any extra bracing for the floor pan? Anyone else consider this?

Ian

 

[Brett James-McCall]

Here's my Roy Smart GTD chassis and the mods Roy and myself did to the sills.

 

[Howard Jones]

Simon, Have a look at Derek Bells website and pay special attention to the suspension geometry section. The GTD will really respond to the improvements he speaks about. Especially at the rear.

I will leave it to you to do some preliminary study. As a start as you put the car back together you should plot the suspension travel/camber change, both front and rear, caster adjustment range, and bump steer.

All this stuff should be done before you start putting the panels back on so that you can weld on any new mounting points etc.

I am trying to get you to come to your own conclusions because there's just to much to put into writing here. At the minimum you need to fix the excessive camber gain at the rear and the bad bump steer at the front.

By the way, there's really a lot of potential improvement for very little money. Just a little sweat equity and some time with a welder.

Let me know when you are ready to start making things I have some ideas that don't cost much to do if you make them yourself.

 

[Simon]

Thanks Howard, I had a look....VERY informative!

 

[Keith]

I thought the section on his Lola set-up was the clearest suspension explanation I've seen in a while.

I did post the link to Derek Bell on the bump steer thread some time ago but they were all so engrossed in the "competition" that they missed it!

Good site....

 

[Brett James-McCall]

Have I missed what Derek did in the end in his articles? I have been trying to scan read them in between meetings this morning, but can't actually see what the final results delivered. Can anyone point me at the piece that explains what he finally did?

Brett

 

[Brett James-McCall]

In case you want to see Howard putting Derek'd work into action its here: http://www.gt40s.com/forum/gt40-tech-chassis-fuel-brakes-wheels-electrics/16176-gtd-rear-suspention-mod.html