Beefy's Midlana Build

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Midlana1
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Re: Beefy's Midlana Build

Postby Midlana1 » 04 Aug 2014, 13:12

There are two rules of thumb when it comes to rack length and position.

1. A line drawn through the outboard and inboard steering ball joints points at the suspension instant centers.
2. The inboard steering balljoints should be on a line connecting the upper and lower inboard suspension points.

FWIW, the entire front suspension was designed around using an unmodified (neither lengthened nor shortened) Miata rack. I worry about what you'll end up with... With the chassis 4" wider the rack needs to be 4" longer than a Miata rack. I've seen ways of doing that, basically building a U-shaped adaptor that the existing rack fits inside of, which extends the inboard pivots outboard to where they need to go. I'm pretty sure you'll have to do something like that.

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Re: Beefy's Midlana Build

Postby b33fy » 04 Aug 2014, 14:05

Thanks Kurt, I get point 1, though I have found a differing view on point 2 I understood the tie rod could be offset as long as it points to the centre. Linkage here probably explains it better than I can.. http://www.circletrack.com/chassistech/ctrp_1001_bump_steer_explained/viewall.html I don't want to open a can of worms and start a long debate on this as I've seen on other forums, though any thoughts and comments and a relatively straight forward solution would be most welcome :)

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Re: Beefy's Midlana Build

Postby Midlana1 » 04 Aug 2014, 14:25

That first picture matches what I was trying to say:

http://www.circletrack.com/chassistech/ctrp_1001_bump_steer_explained/photo_02.html

They also said much the same: "In order for your car to have near zero bumpsteer, two conditions need to exist. The tie rod needs to point at the instant center and its length needs to be specific to the inner mounts and the ball joints."

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Re: Beefy's Midlana Build

Postby b33fy » 04 Aug 2014, 14:46

Midlana1 wrote:That first picture matches what I was trying to say:

http://www.circletrack.com/chassistech/ctrp_1001_bump_steer_explained/photo_02.html

They also said much the same: "In order for your car to have near zero bumpsteer, two conditions need to exist. The tie rod needs to point at the instant center and its length needs to be specific to the inner mounts and the ball joints."


Yep fully understand Kurt, the tie rod needs to be a set length which is set by the distance between the inner and outer suspension pivot point centre lines, if it is offset from those lines it still needs to be the same lenght. Thanks for helping me to understand this a bit more.

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Re: Beefy's Midlana Build

Postby Midlana1 » 04 Aug 2014, 15:24

Like I said, you may well be able to use the rack you have if an adaptor is added to move the pivots outward to where they need to be.

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Re: Beefy's Midlana Build

Postby b33fy » 05 Aug 2014, 09:34

Midlana1 wrote:Like I said, you may well be able to use the rack you have if an adaptor is added to move the pivots outward to where they need to be.


Thanks Kurt, currently I'm looking to extend the rack with 3" extensions/adapters which will then accept a new pair of MX5 drumsticks/ball joint. I think its been thought through a little more thoroughly now :)

Seats have arrived so I'll mess about with those for now (after all, what could go wrong?.... :D .)

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Re: Beefy's Midlana Build

Postby b33fy » 07 Aug 2014, 12:42

Seats have gone wrong...some more new ones now being made, might get them in six weeks time, meanwhile here's an image of one of the new (old) seats to remind me what I had for a fleeting moment... :roll:

Image

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Re: Beefy's Midlana Build

Postby Midlana1 » 07 Aug 2014, 13:16

What was wrong with them?

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Re: Beefy's Midlana Build

Postby b33fy » 07 Aug 2014, 14:19

The fixings were in the wrong place which meant they didn't fit the runners unless you elongated a hole and fitted them upside down. This mean't when you operated the seat the handle slid under the seat jammimng it and making it inoperable. The runners were bought on the recommendation of the seat company as the seats were specifically designed for them. Unfortunately the company chose to design the seat so the runners would only fit the wrong way up..thinking it was the correct way. The two halfs of each runner are different lengths needless to say the shorter one (the right one) is too short to cover the fixings in the seat. I was offered some weld on extensions for the runners, which I politely declined on safety grounds, so new seats are being made. Credit to the company for putting their hands up and sorting so quickly. Very frustrating from my perspective as I've got a bit of a window with my studies which enables me to get a bit done with the car if I can. I know seats are a very personal thing, I do particularly like these seats and the integral bases mean they are at the correct angle etc

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Re: Beefy's Midlana Build

Postby Langan » 08 Aug 2014, 10:13

Are those for sale? If price is rite worth fixing.


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