Camber plates?
12-14-2008, 02:37 PM
#1
Elite Member
Thread Starter
iTrader: (12)
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,850
Total Cats: 71
Camber plates?
Sooooo I've decided that I want some adj. camber plates for when I go to the track. But where/what camber plates do I need to get? I have Ohlins DFV coilovers, if that makes any difference.
Reply
0
0
12-14-2008, 03:07 PM
#3
Junior Member
Join Date: Nov 2006
Posts: 158
Total Cats: 0
miata's dont have and cant have camber plates.... we have control arm and with that the only way to adjust camber is with the centric joint on the lower control arm.. or make your own custom control arm or somthing of that matter... sorry
Reply
0
0
12-14-2008, 10:56 PM
#5
Elite Member
Thread Starter
iTrader: (12)
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,850
Total Cats: 71
Eh... I didn't know. I thought i've heard of [miata] people using them, but never really payed attention until having a discussion with a friend of mine. I know what currently controls camber adjustments, but was thinking of something a little easier.
Reply
0
0
12-15-2008, 12:30 AM
#7
Elite Member
Thread Starter
iTrader: (12)
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,850
Total Cats: 71
I would like to be able to adjust the front camber on-the-fly at the track if need be. I was out at TGP last weekend and I couldn't get enough bite out of the front and would liked to have been able to add a touch of front camber to correct the problem...but I couldn't.
Reply
0
0
12-15-2008, 10:00 AM
#9
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,338
Total Cats: 573
and toe
and caster
...
the only way you're going to get camber-only with an easy adjustment is a fancy new control arm with a left-and-right hand thread member and lockscrews. Better get on the horn to TravisR in his "what do you want" thread
and caster
...
the only way you're going to get camber-only with an easy adjustment is a fancy new control arm with a left-and-right hand thread member and lockscrews. Better get on the horn to TravisR in his "what do you want" thread
Reply
0
0
12-15-2008, 05:06 PM
#11
Boost Pope
iTrader: (8)
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,026
Total Cats: 6,592
I think we need to step back for a moment and look at the differences between the double A-arm suspension and the MacPherson strut. Forgive me if this sounds pandering, but there is certainly some confusion on the part of the OP.
In vehicles which use struts, there is only one A-arm per wheel, which is effectively the lower A-arm. The function of the upper A-arm is provided by the strut itself. The wheel hub is rigidly bolted to the lower housing of the strut, and the strut is a functional part of the geometry of the suspension. When the steering wheel is turned, the wheel hub rotates around the strut itself. The camber angle of the wheel is purely a function of the angle at which the strut is oriented, and is adjusted by moving the upper strut mounting point in or out, sideways. Here's a simplified image of a MacPherson suspension:
In most cars, the upper mounting point is fixed, thus the camber angle is non-adjustable. It is dictated by the design of the upper strut mount. Where adjustability is desired, so-called camber plates are employed which permit the upper strut mounting position to be changed.
Now, even though the coil-over-shock design in a Miata resembles a strut, it does not serve the function of one. The camber (and caster) are dictated by the geometry of the upper and lower A-arms, which are adjustable by offset cams at the inboard mounting points of the lower arms. In such a design, the shock does not rotate when the wheel is turned- it is attached to the lower A-arm, not the hub. The shock is basically just along for the ride, so to speak. You can alter the mounting points or even remove the shock altogether, and the geometry of the suspension will be completely unchanged. The hub will continue to move up and down just as before, and retain its camber and caster properties.
From a tuner's standpoint, the double A-arm suspension has some advantages, namely that it provides a considerable amount of adjustability without the need for any aftermarket parts. If even more adjustability is required, you can always install offset bushings in the upper arms, to bias the hub in or out by a certain amount. The downside to this design as that, as Y8s notes, turning one cam affects both camber and caster (and toe, to a certain degree, though the toe adjustment is made at the tie rod ends.) In theory, turning both adjusters by the same amount in the same direction should change camber without altering caster, but I'm sure it's a tricky business.
Somebody one made some very fancy control arms for the Miata, and for the life of me I can't seem to find a link or any further info. Apart from being red and shiny, I don't really recall what performance advantages they were said to offer. Obviously, if one could change the position of the upper or lower balljoints independently, this would be an excellent camber adjusting technique. The upper BJ is captive to the upper arm, but I can see someone potentially coming up with a mechanism that allows some adjustment of the lower BJ, possibly involving offset bushings or shims.
Here's an interesting bit of suspension pr0n: Yaw Power Products / Miata Race Suspension
And some good reading on the subject: http://forum.miata.net/vb/showthread.php?t=171585&
And some extremely hardcore A-arm pr0n, for you fab junkies: http://forums.turbobricks.com/showthread.php?t=63803
In vehicles which use struts, there is only one A-arm per wheel, which is effectively the lower A-arm. The function of the upper A-arm is provided by the strut itself. The wheel hub is rigidly bolted to the lower housing of the strut, and the strut is a functional part of the geometry of the suspension. When the steering wheel is turned, the wheel hub rotates around the strut itself. The camber angle of the wheel is purely a function of the angle at which the strut is oriented, and is adjusted by moving the upper strut mounting point in or out, sideways. Here's a simplified image of a MacPherson suspension:
In most cars, the upper mounting point is fixed, thus the camber angle is non-adjustable. It is dictated by the design of the upper strut mount. Where adjustability is desired, so-called camber plates are employed which permit the upper strut mounting position to be changed.
Now, even though the coil-over-shock design in a Miata resembles a strut, it does not serve the function of one. The camber (and caster) are dictated by the geometry of the upper and lower A-arms, which are adjustable by offset cams at the inboard mounting points of the lower arms. In such a design, the shock does not rotate when the wheel is turned- it is attached to the lower A-arm, not the hub. The shock is basically just along for the ride, so to speak. You can alter the mounting points or even remove the shock altogether, and the geometry of the suspension will be completely unchanged. The hub will continue to move up and down just as before, and retain its camber and caster properties.
From a tuner's standpoint, the double A-arm suspension has some advantages, namely that it provides a considerable amount of adjustability without the need for any aftermarket parts. If even more adjustability is required, you can always install offset bushings in the upper arms, to bias the hub in or out by a certain amount. The downside to this design as that, as Y8s notes, turning one cam affects both camber and caster (and toe, to a certain degree, though the toe adjustment is made at the tie rod ends.) In theory, turning both adjusters by the same amount in the same direction should change camber without altering caster, but I'm sure it's a tricky business.
Somebody one made some very fancy control arms for the Miata, and for the life of me I can't seem to find a link or any further info. Apart from being red and shiny, I don't really recall what performance advantages they were said to offer. Obviously, if one could change the position of the upper or lower balljoints independently, this would be an excellent camber adjusting technique. The upper BJ is captive to the upper arm, but I can see someone potentially coming up with a mechanism that allows some adjustment of the lower BJ, possibly involving offset bushings or shims.
Here's an interesting bit of suspension pr0n: Yaw Power Products / Miata Race Suspension
And some good reading on the subject: http://forum.miata.net/vb/showthread.php?t=171585&
And some extremely hardcore A-arm pr0n, for you fab junkies: http://forums.turbobricks.com/showthread.php?t=63803
Reply
0
0
12-15-2008, 05:20 PM
#13
Boost Pope
iTrader: (8)
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,026
Total Cats: 6,592
Ah, here we are. 'Twas Randy Stocker who made the arms I'm thinking of:
As you can see, even though they use spherical bearings, the basic philosophy of adjustment is the same as stock.
As you can see, even though they use spherical bearings, the basic philosophy of adjustment is the same as stock.
Reply
0
0
