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Custom adjustable upper control arms

Old 05-25-2018, 08:39 AM
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Custom adjustable upper control arms

I'm unable to get as much front negative camber as I would like without excessively low ride height, even with offset front UCA bushings. I found a company that will make custom UCA's for the car and have a set on order. The owner has a set of stock ones I sent him - the new ones will go from stock dimensions to moving the ball joint inboard 3 cm or so.


Michigan Metal Works



They will look similar to this.


http://michiganmetalworks.com/wp-con...2/IMG_8511.jpg


Anyway, there is some cost savings if he makes 3 sets ($600 versus $650 per set). I'm only getting one set so if anyone else is interested please let me know. Powdercoating is $80 more.


Alan
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Old 06-23-2018, 03:27 AM
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Japspeed and I think Megan both make front upper control arms with adjustable ball joints.. and I think it's closer to 300 a set..
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Old 06-23-2018, 06:31 AM
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Megan racing
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Old 06-24-2018, 07:00 PM
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Originally Posted by John V View Post
Megan racing

Megan "Racing"


FTFY!
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Old 06-25-2018, 08:53 PM
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I don't trust their (Megan/Jap) adjuster design to stay put under race conditions.
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Old 06-29-2018, 11:29 AM
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You can also check out Enjuku racing they have a set for 265. The Michigan Metal unit looks like a better overall design allowing you adjust caster.
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Old 07-01-2018, 03:00 PM
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I wish there was a good option out there... and something that would be DSP legal for SCCA stuff.

The Michigan Metal ones have one flaw... by changing the camber you are changing the distance between the inner mounting points. Can't have a triangle with one angle the same and different length legs without affecting the third side length too. Most fully adjustable control arm kits use a ball joint assembly with two double heim jointed arms, on the inside and outside, to solve that issue. I'd be willing to bet either the attachment points on the car or the welds to the ball joint cup will fail eventually in race conditions on those ones.

I agree on the Megan ones not looking robust enough, but I had the idea of either adding a threaded spacer to control inboard slip, or just welding the slider in place once I had it where I wanted it.
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Old 07-01-2018, 04:19 PM
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Originally Posted by roflcopter View Post
I wish there was a good option out there... and something that would be DSP legal for SCCA stuff.

The Michigan Metal ones have one flaw... by changing the camber you are changing the distance between the inner mounting points. Can't have a triangle with one angle the same and different length legs without affecting the third side length too. Most fully adjustable control arm kits use a ball joint assembly with two double heim jointed arms, on the inside and outside, to solve that issue. I'd be willing to bet either the attachment points on the car or the welds to the ball joint cup will fail eventually in race conditions on those ones.

I agree on the Megan ones not looking robust enough, but I had the idea of either adding a threaded spacer to control inboard slip, or just welding the slider in place once I had it where I wanted it.

You are correct of course. We looked at making them with the adjusters parallel but got worried that there was not enough space to make it work so we are just making them non-adjustable (moving the ball joint inboard 2 cm) and using the stock adjustment in the LCA to fine-tune it.


AC
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Old 07-03-2018, 07:08 AM
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even with the whiteline offset camber bushings, i can still use some more camber. the megan doesn't look that bad. can probably add a few more gussets to it and it will be fine.
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Old 07-07-2018, 01:56 PM
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Other than it makes no sense to move it 3 cm inboard (1.2”)

that has to be something crazy, like 20+ degree camber or something, or maybe you meant 3mm (0.12”)

Start reading here instead, unfortunately there’s a lot of back and forth banter for several pages to get the full jist of it. Generally speaking, -4 deg is more than you’ll likely ever need

https://www.rx8club.com/rx-8-racing-...1/#post4824128
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Old 07-08-2018, 07:57 PM
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too much static camber and you'll reduce contact patch for straight line braking.
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Old 07-09-2018, 07:10 AM
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Originally Posted by trackjunkie View Post
too much static camber and you'll reduce contact patch for straight line braking.

To some degree. The question is, how much is too much? The sidewalls flex some, when the weight transfers to the front under heavy braking, which increases the size of the contact patch.


I can tell you -3.5* is not too much in either my RX-8 or Miata. Both run that much front static camber, and both have ample braking performance.
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Old 07-09-2018, 08:05 PM
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Hoosier specifies ~3 degrees for the A7/R7, but that is camber at load though. Has anyone done a plot of the camber curve during stroke on the RX8? I actually plan to do this sometime this week while I have the shocks out... who has suspension position sensors and can provide a realistic range of displacement during racing conditions?
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Old 07-10-2018, 06:15 AM
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-3.5 is without a doubt not too much for a double wishbone car. I run around -4.5 on a car with struts.
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