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Discussion Starter #1
Hey All,

I'm working with a CNC shop to make some Roll Center Adjusters for the Mk2 Supra. I have a few prototype models made to test, and think we can work out the kinks such that the units will be quite nice and a good fit.
If there are 9-10 people that would like a set, send me a message or email. Cost should be about $100 a set. Once I am satisfied the units can be made to fit ok, I'll let the group know and ask for not only a head count, but ask for payments.

Check out Technotoytuning.com for a good description of these items. I'm honestly not convinced everyone with a lowered car needs them, but for those members wanting to correct bump steer and roll steer as a result of lowering the car, this is the way to do it.

Don L.
 

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I just ordered a set from TTT for an ae86. Talking with Gabe he is interested in making a set if there is demand. Especially since he should be able to use the blanks from the ae86. Maybe you should check with him first, as his are only $70, and he's willing to make em. I gave him the celicasupra website so he can check it out. I can give him another call if you like.

Either way we go, I'm down for a set. What thickness are you planning to make em Don?

Christian
 

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yeah I may be intersed in a set too. I'm thinking 1 or 3/4 inch would be good as I don't want to lose too much of my new found camber, I'm having too much fun with it :D But it would be nice if they came in a variety of sizes.
 

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Discussion Starter #4
It would be great to get them from TTT as I would certainly trust their work. Thing is, when I contacted them a few weeks ago they said no RCA for our car. Since then another member mentioned they might make some later in summer if strut housing/steering knuckle could be brought in for measuring. As usual, I was working on a faster schedule, and got a few prototypes done. Not completely happy yet, but it looks very obtainable. I working with a 30mm thickness, a bit more than 1 & 1/8".
Thats the thickness of the AE86 models. I figured most people would lower their fronts at least 1", and I've certainly dropped my much more than that. I won't move forward with this until I can test them on my car for fitting and function. This really isn't a very difficult project per se, just getting a AE86 RCA to copy, but change the dimensions and hole spacing accordingly. Problem is getting any CNC shop to work with such small quantities. Thus the price gets crazy. I was quoted $90 each for a short run, I was shooting for $100 a pair shipped with a group of 10 pairs.
Anybody with CNC connections to work on alum 6061 out there ?

Don L.
 

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Discussion Starter #5
BTW, the RCA should not affect any static alignment settings. eg, not affect on camber, caster, toe, at static. The benefit is the lessening of changes to alignment upon spring/susp compression.
I have to reiterate, I believe most owners with Eibachs/ST springs, etc won't feel the need for these. So the demand I understand may be limited, thus my effort to feel out the interest.

Don L
 

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I'll most likely take a set for that price. It would be nice to restore the factory arm geometry. You shouldn't have too hard of a time finding a place that will make small quantities, the only trick is that you will pay for it. You might try Encore Industries, they are a medium sized sheet metal/machining shop in Santa Clara IIRC. Not sure if they are in the phone book, but I have the # at work. They do pretty nice work. They've been doing a lot of the simpler machine and sheet metal parts at work lately. They shouldn't have any problems making a set of RCAs.
 

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Discussion Starter #8
Jim, I bet those guys working on the BBK could do RCAs too. Maybe this pricing that the shop I'm working with is too high. I know their quality is good, but they won't work on just a few. To me, it seems they should cost maybe $40 a pair, but I guess this area is just overpriced.
Let me know if anyone out there wants to arrange better pricing.

Don L.
 

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So these RCAs restore the front lower control arm to the stock position thus restoring the stock geometry. I'm interested. I'm big on suspension mods.

What are the problems associated with not using RCAs and a lowered front end for those who don't know much about racing?
 

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Discussion Starter #10
Well Josh, not using RCA with a lowered front end (like Eibachs or ST) is probably no big deal. Not that I mean to dampen enthusiasm for these things, but heck, I drove a number of years on Eibachs with no apparent problem. The issue is that a lowered front end will be subject to more toe changes upon hitting bumps in the road, cornering hard. This would be apparent with less responsive steering upon corner entry, less ultimate tire grip (front tires) in the turn itself, and if you hit a bump in the middle of a turn, the car would change direction somewhat. The RCAs won't make much difference for driving around town (for most folks), probably no help in drag racing, but if you drive turns hard, autox, or do track events, I think they would be a good mod (if the car is lowered in front).
Even though my car is lowered quite a bit, the springs are very stiff and the sway bar is huge, there is still some susp compression in hard turns, and initial turn in on corners is not as good as I would like.

Don L.
 

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If you can get some made up for a reasonable ammount, I'll buy a set.
 

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Don L. said:
Jim, I bet those guys working on the BBK could do RCAs too. Maybe this pricing that the shop I'm working with is too high. I know their quality is good, but they won't work on just a few. To me, it seems they should cost maybe $40 a pair, but I guess this area is just overpriced.
Let me know if anyone out there wants to arrange better pricing.

Don L.
Send me some preliminary designs with dimensions.

Yes, the material cost is cheap, maybe $5 max for a billet.
Probably less.

It's all setup time, and how many machining operations.
 

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I am in, if the price is reasonable. Something to correct the rear camber for those with ST's or Eibachs would be an even bigger seller!!! I am getting ready to dump $800 on tires and cringe at how they are going to be trashed by my rear camber.
 

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OK forgive my ignorance, but what do the role centre adjusters do? Does it have anything to do with Camber?

-Andrew
 

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Andrew said:
OK forgive my ignorance, but what do the role centre adjusters do? Does it have anything to do with Camber?

-Andrew
:? Im with Andrew :?
 

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Does it have anything to do with Camber?
No. They push the lower control arm back down into the stock postition to minimize bump steer. Bump steer is basically when you hit a bump and the suspension compressing cause one wheel to change its steering angle, so the car darts to one side when you are supposed to be going in a straight line. The more the suspension is compressed the more acute the bump steer is. Basically as the arm goes up the more the wheel toes inward. This is a function of the steering/suspension geometry
 

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Ok, to what I was readign was that if I lower my car with lets say ST springs and if I had some 15" rims it would be recomended to buy these for my car? (BTW I drive regularly through the twisties :wink:)

one more thing, if I bought some of these, would some one be able to provide (me) some kind of write up so that even a blind person can install them. :wink: :lol:
 

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Sure, especially since they are pretty reasonable. They definetly won't hurt the handling. If you can install the spring you should be able to install these spacers. They just go between the strut and the knuckle arm. So it should be two very hard to loosen bolts and slip in the spacer and installation is the reverse of removal type deal.
 
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