Front - Rear track width and transition while cornering..?

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killaz
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Re: Front - Rear track width and transition while cornering.

Post by killaz » Wed Nov 02, 2016 1:31 pm

This is position of my rear coilover atm, left wheel from behind. Once when I replace fuel tank with fuel cell, I plan to move them a bit closer to factory spring perch. Upper side of coilovers would enter just a bit in the boot...
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Duk
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Re: Front - Rear track width and transition while cornering.

Post by Duk » Wed Nov 02, 2016 6:05 pm

Nice!
With the springs being out there they'll definitely resist body roll more than springs in the standard positions. Remove 1 of the antiroll bar's links and see what the car is like then. If that's too soft in rear roll resistance, then you could modify the rear antiroll bar so that you can soften it. Or use a thinner bar.

You should have those mounting points fully welded onto the Dedion tube. The vertical welds will be much better at resisting the bump forces.

Thanks for sharing your custom work. 8)
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killaz
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Re: Front - Rear track width and transition while cornering.

Post by killaz » Sat Nov 05, 2016 1:58 am

Thanks! This is provisional position, I tend to do some aditional mods and welding. I'll post pictures when finished.

First things first, front end higher rate springs and bump steer correction.
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Re: Front - Rear track width and transition while cornering.

Post by killaz » Fri Nov 11, 2016 9:30 am

One question; bump steer can be corrected with additional positive caster? Idea is to reduce camber from -3,0 to -2,0 and add more caster.

My long shank upper ball joints are 20mm longer than those from factory... Heres photo of some additional custom work :)
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Control arm & upper ball joint
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Duk
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Re: Front - Rear track width and transition while cornering.

Post by Duk » Fri Nov 11, 2016 9:10 pm

killaz wrote:One question; bump steer can be corrected with additional positive caster? Idea is to reduce camber from -3,0 to -2,0 and add more caster.

My long shank upper ball joints are 20mm longer than those from factory... Heres photo of some additional custom work :)
Unfortunately not.
I thought that becuase the front suspension toed in with bump, I had to lower the outer tie rod end, which more caster would have helped to do. But becuase the top ball joint is now higher, I finally realised that I had to raise the outer tie rod end.
And that's the reason for the spherical rod end, it's attachment point is central to the body of the rod end, so the pivot point is raised.
You would have to reduce the caster angle to try and get bump steer lower.
And from some simple modeling that I did of the front suspension shows a steering axis inclination angle of about 5 degrees. Ideally you want your caster angle higher than the steering axis inclination angle. At 4.5* standard, it's not even enough.
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killaz
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Re: Front - Rear track width and transition while cornering.

Post by killaz » Tue Dec 27, 2016 8:58 am

I've inspected bump steer and it was close to zero. Then, I checked caster and it was waaaay off (arround 3 degree in total) thanks to local alignment shop. I'll go for more aggressive caster and recheck for bump steer, starting from spring 2017...
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