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-   -   Relocating my lower control arms (https://www.rx7club.com/1st-generation-specific-1979-1985-18/relocating-my-lower-control-arms-556194/)

MosesX605 07-04-06 11:46 AM

Relocating my lower control arms
 
Well I'm too poor for coil-overs and too unsatisfied with the amount of adjustment in my camber plates. Time to change the equation!

Let's move the lower control arm outboard!

If I've figured it right, moving the control arm outboard 3/4 of an inch will result in a gain of -2 deg camber.

My question is this:

Has anyone here done this? Do the tie-rod adjusters and tension rods have enough room for that kind of outboard movement?

Thanks!

rbf41182gt 07-04-06 01:14 PM

racing beat sells adjustable control arms

$375 for the pair, but up to 4.4 degrees of negative camber

custom13B 07-04-06 01:17 PM

I think you have the right idea but moving them that much would create problems with the tie rods for sure. Another option is to cut the end off the stock control arms..weld on a steel plate and then drill and tap it to accept spherical rod ends. But if you do this use heavy duty rod ends and make sure to weld that plate securely. You also loose your rubber bushings entirely so it may ride a bit harsh. But then you have maximum adjustability. Exerything involves comprimise with cars,good luck.

MosesX605 07-04-06 06:18 PM

I know RB sells a set of adjustable arms, but if I'm not willing to shell out for coil overs, what do you think the likelyhood of me plunking $375 on the table for the RB product?

While we're on the subject of the RB adjustable arms, since they can be adjusted more than double the length that I want to move my control arm outboard by, doesn't it stand to reason that there is enough slack in the tie rods/tension rods to compensate?

RXn407 07-04-06 06:25 PM

If not, like the man above stated you could get some from an industrial catalog.the issue is making sure they are strong enough. Also have you thought instead of moving the lower arms out, Since youre inventing have you thought of the possibilities for adjusting the camber from the tower and doing some re working from there? just shooting ideas. good luck!!
Oh yeah, and the lowrider guys w/ hydralics cut and extend control arms all the time so maybe if you have a hydraulic shop in your area they might be able to help.
-erik

NTRX7 07-04-06 07:15 PM

lower control arms
 
i have read on the Ausrotary forum of guys moving the lower control arms out by redrilling the the mounting point on the cross member, i also remember them saying there was a limit due to clearance problems. do a search on WWW.Ausrotary.com and see how ya go.

Cheers Paul

31rx7 07-04-06 08:33 PM

Interestingly, I have a set of offset bushings made of poly urethane for the front control arms that I inherited with my race car. I suspect that they move the mounting point out by 3/8" or so.

Unfortunately, I have never installed them to see the impact on camber, and I have no clue as to who manufactured them.

peejay 07-04-06 08:40 PM


Originally Posted by MosesX605
My question is this:

Has anyone here done this? Do the tie-rod adjusters and tension rods have enough room for that kind of outboard movement?

*BARELY*. Longer adjusters would be recommended.

There's something like an inch of adjuster in each tie rod end with stock geometry. Maybe less, I've forgotten the figures.

MosesX605 07-04-06 09:16 PM


Originally Posted by peejay
*BARELY*. Longer adjusters would be recommended.

There's something like an inch of adjuster in each tie rod end with stock geometry. Maybe less, I've forgotten the figures.

Where would one go to find longer adjusters?

peejay 07-04-06 11:50 PM

That, I dunno. :)

My guess would be, bite the bullet and get some Coleman (?) studs and convert to rod-ends for the steering. But there goes the cheap factor...

MosesX605 07-04-06 11:53 PM

Are the threads reversed on the adjuster, or are they the same on both ends?

If they're the same, I should be able to find myself a long bolt with the right thread pitch somewhere...

Bruceman 07-05-06 09:56 AM


Originally Posted by MosesX605
Let's move the lower control arm outboard!

If I've figured it right, moving the control arm outboard 3/4 of an inch will result in a gain of -2 deg camber.

My question is this:

Has anyone here done this? Do the tie-rod adjusters and tension rods have enough room for that kind of outboard movement?

Thanks!

I have done this. It is very difficult to do it acurately/equal side to side. It is possible and the tie rods and tension rods have plenty of adjustment. It is not legal for SCCA CSP autocross.
I have reverted back to the standard holes after changing to good camber tops.
You will get less than 2 degrees more like 1 degree extra. But how much do you need? Depending on your ride height a good camber top will get 2.5 degrees negative.

MosesX605 07-05-06 12:07 PM


Originally Posted by Bruceman
I have done this. It is very difficult to do it acurately/equal side to side. It is possible and the tie rods and tension rods have plenty of adjustment. It is not legal for SCCA CSP autocross.
I have reverted back to the standard holes after changing to good camber tops.
You will get less than 2 degrees more like 1 degree extra. But how much do you need? Depending on your ride height a good camber top will get 2.5 degrees negative.

It's legal up here in Kaniukistan for CSP so no worries there. I have camber/caster adjusters installed right now but don't have the coin for coil-overs so my adjustment is limited by the large size of the upper coils. Thanks for the input!

aussiesmg 07-05-06 04:33 PM

My RX3 in Australia had this done, I had just enough tie rod to be safe, JUST. I ran 3 1/2 degrees neg usually and had no issues, I used crash bolts so any difference in the sides can be dialled out in the alignment process.

If price is your biggestissue check these out they are well priced. www.racersareme.com

Oh, and the threads are opposite on the tie rod adjuster this is how they are lengthened or shortened as required

Steve

MosesX605 07-05-06 06:03 PM


Originally Posted by aussiesmg
My RX3 in Australia had this done, I had just enough tie rod to be safe, JUST. I ran 3 1/2 degrees neg usually and had no issues, I used crash bolts so any difference in the sides can be dialled out in the alignment process.

If price is your biggestissue check these out they are well priced. www.racersareme.com

Oh, and the threads are opposite on the tie rod adjuster this is how they are lengthened or shortened as required

Steve

Thanks!

I'll be sure and report back with pictures.

peejay 07-09-06 09:52 AM

OK.

I recall that the adjusters are 4 1/2" long end to end.

My car as it sits has exactly 3" from tie-rod end to tie-rod end. That makes 3/4" in each end.

You want to have at LEAST the root diameter threaded into something, and root diameter IIRC is 14mm, or 9/16". This means the control arm can be relocated a maximum of 3/8" before things start to get iffy. Hrmm.

wallyrx7 09-09-12 09:06 AM

I'm bringing this thread back to life!

so I want to move my control arms outward on the cross member. Everyone seems to be talking about this like you can move it 1 1/2 inches but when I took everything apart... the engine mounting brackets are in the way!

So the mounts are just a box so I could go inside but then I would be raising the hole...

Anyone who has done this can you provide some help?

https://www.rx7club.com/members/rty-...&mode=gnr_rand

wallyrx7 09-09-12 09:21 AM

https://www.rx7club.com/members/wall...smember-48367/

j9fd3s 09-09-12 02:40 PM


Originally Posted by wallyrx7 (Post 11215610)
I'm bringing this thread back to life!

so I want to move my control arms outward on the cross member. Everyone seems to be talking about this like you can move it 1 1/2 inches but when I took everything apart... the engine mounting brackets are in the way!

So the mounts are just a box so I could go inside but then I would be raising the hole...

Anyone who has done this can you provide some help?

https://www.rx7club.com/members/rty-...&mode=gnr_rand

this is an advanced move, because you're fundamentally changing the geometry of the front suspension, in three directions!

moving the hole UP. this might be good. ideally you want the inner pivot point to be about 5/8" higher than the outer pivot point, this keeps roll center in a good place. so if you move the inner pivot UP, the car can be lower, while still keeping the 5/8" number.

moving the hole OUT. this does two things. it adds negative camber, and increases front track width. negative camber is good, however HOW MUCH really depends on what you're using the car for. a street car is totally fine with -.5 to -1 degree, which you can almost do with just stock parts. race cars need more, but how much more depends on tires. a big fat radial slick might only want -1 to -2, but the 195/60/13 Ra1's they used to run in pro7 want like -6!

the third thing is track width. this matters. especially if you make one end wider than the other. on a car with sticky tires, 10mm of track width can be a big change.

so moving the hole might be good, but you really should know what you're after, and its probably not needed on a street car at all.

84stock 09-09-12 06:34 PM

Did the negative camber make steering tougher (harder to turn the wheel)?

wallyrx7 09-10-12 08:29 AM


Originally Posted by j9fd3s (Post 11215883)
this is an advanced move, because you're fundamentally changing the geometry of the front suspension, in three directions!

moving the hole UP. this might be good. ideally you want the inner pivot point to be about 5/8" higher than the outer pivot point, this keeps roll center in a good place. so if you move the inner pivot UP, the car can be lower, while still keeping the 5/8" number.

moving the hole OUT. this does two things. it adds negative camber, and increases front track width. negative camber is good, however HOW MUCH really depends on what you're using the car for. a street car is totally fine with -.5 to -1 degree, which you can almost do with just stock parts. race cars need more, but how much more depends on tires. a big fat radial slick might only want -1 to -2, but the 195/60/13 Ra1's they used to run in pro7 want like -6!

the third thing is track width. this matters. especially if you make one end wider than the other. on a car with sticky tires, 10mm of track width can be a big change.

so moving the hole might be good, but you really should know what you're after, and its probably not needed on a street car at all.

Great, thanks for the advice. This is a full race car (read as Lemons car) so this is why I am not buying camber plates and doing things correctly :)

I have a pic of the cross member and hole but am forum illiterate and so can't figure out how to post it.

I will plan on moving the hole upwards then. This makes sense to me because we are at the same time putting springs on the car to lower it, so if we lowered the car by 5/8 inch and raised the mounting point by the same, we would end up even as far as suspension geometry! (please don't call me out on my logic...)

j9fd3s 09-10-12 09:51 AM


Originally Posted by wallyrx7 (Post 11216629)
Great, thanks for the advice. This is a full race car (read as Lemons car) so this is why I am not buying camber plates and doing things correctly :)

I have a pic of the cross member and hole but am forum illiterate and so can't figure out how to post it.

I will plan on moving the hole upwards then. This makes sense to me because we are at the same time putting springs on the car to lower it, so if we lowered the car by 5/8 inch and raised the mounting point by the same, we would end up even as far as suspension geometry! (please don't call me out on my logic...)

yeah seems like that should work


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