Notices
RX-8 Racing Want to discuss autocrossing, road-racing and drag racing the RX-8? Bring it here. This is NOT a kills/street racing forum.

Custom adjustable upper control arms

Old 05-25-2018, 08:39 AM
  #1  
Registered
Thread Starter
iTrader: (2)
 
Adax's Avatar
 
Join Date: Nov 2016
Posts: 208
Received 18 Likes on 15 Posts
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
Old 06-23-2018, 03:27 AM
  #2  
New Member
iTrader: (2)
 
Woldy's Avatar
 
Join Date: Sep 2016
Location: Minneapolis, MN
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
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..
Old 06-23-2018, 06:31 AM
  #3  
Not ******
iTrader: (1)
 
John V's Avatar
 
Join Date: Jan 2004
Posts: 987
Received 64 Likes on 59 Posts
Megan racing
Old 06-24-2018, 07:00 PM
  #4  
Water Foul
 
Steve Dallas's Avatar
 
Join Date: May 2013
Location: Republic of Texas
Posts: 2,521
Received 257 Likes on 210 Posts
Originally Posted by John V
Megan racing

Megan "Racing"


FTFY!
Old 06-25-2018, 08:53 PM
  #5  
Registered
Thread Starter
iTrader: (2)
 
Adax's Avatar
 
Join Date: Nov 2016
Posts: 208
Received 18 Likes on 15 Posts
I don't trust their (Megan/Jap) adjuster design to stay put under race conditions.
Old 06-29-2018, 11:29 AM
  #6  
Registered
 
jayh's Avatar
 
Join Date: May 2017
Posts: 48
Likes: 0
Received 2 Likes on 2 Posts
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.
Old 07-01-2018, 03:00 PM
  #7  
Registered
iTrader: (2)
 
roflcopter's Avatar
 
Join Date: Jun 2011
Location: Destin
Posts: 316
Likes: 0
Received 3 Likes on 3 Posts
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.
Old 07-01-2018, 04:19 PM
  #8  
Registered
Thread Starter
iTrader: (2)
 
Adax's Avatar
 
Join Date: Nov 2016
Posts: 208
Received 18 Likes on 15 Posts
Originally Posted by roflcopter
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
Old 07-03-2018, 07:08 AM
  #9  
Registered
 
trackjunkie's Avatar
 
Join Date: Oct 2017
Location: South Central PA
Posts: 611
Received 60 Likes on 45 Posts
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.
Old 07-07-2018, 01:56 PM
  #10  
No respecter of malarkey
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 26,719
Received 2,006 Likes on 1,635 Posts
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
Old 07-08-2018, 07:57 PM
  #11  
Registered
 
trackjunkie's Avatar
 
Join Date: Oct 2017
Location: South Central PA
Posts: 611
Received 60 Likes on 45 Posts
too much static camber and you'll reduce contact patch for straight line braking.
Old 07-09-2018, 07:10 AM
  #12  
Water Foul
 
Steve Dallas's Avatar
 
Join Date: May 2013
Location: Republic of Texas
Posts: 2,521
Received 257 Likes on 210 Posts
Originally Posted by trackjunkie
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.
Old 07-09-2018, 08:05 PM
  #13  
Registered
iTrader: (2)
 
roflcopter's Avatar
 
Join Date: Jun 2011
Location: Destin
Posts: 316
Likes: 0
Received 3 Likes on 3 Posts
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?
Old 07-10-2018, 06:15 AM
  #14  
Not ******
iTrader: (1)
 
John V's Avatar
 
Join Date: Jan 2004
Posts: 987
Received 64 Likes on 59 Posts
-3.5 is without a doubt not too much for a double wishbone car. I run around -4.5 on a car with struts.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Olorin2
Series I Wheels, Tires, Brakes & Suspension
6
04-06-2014 04:04 AM
TeamRX8
RX-8 Parts For Sale/Wanted
26
12-02-2011 04:16 PM
WhiteSnowflake8
Series I Wheels, Tires, Brakes & Suspension
18
09-16-2009 06:11 PM
Xantium
Series I Wheels, Tires, Brakes & Suspension
10
02-22-2007 08:28 PM
SPACE WRANGLER
NW RX-8 Forum
2
01-07-2007 02:54 PM


Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: Custom adjustable upper control arms



All times are GMT -5. The time now is 08:57 PM.