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Author Topic:   metric upper a-arms
Timmer
Dirt Roller

Total posts: 7
posted November 14, 2005 07:23 PM  
Has anybody found a way to make these work.Are rules require we use oem parts.We can reinforce the a-arm with tubing along the edge.Has anybody looked at turning the a-arms upside down and putting left on right etc.etc.Notching out some of the a-arm for frame clearance is not a problem since we can reinforce.Maybe make a spacer between a-arm and ball joint?

Larry Seals
Dirt Full Roller

Total posts: 50
posted November 29, 2005 06:01 AM  
Are you looking for strength or trying to fix caster camber problem on left front?

Timmer
Dirt Roller

Total posts: 7
posted November 29, 2005 04:21 PM  
Larry what im trying to improve is the roll center.With a oem upper a-arm the pivot point of the ball joint is below the pivot point of were the a-arm is mounted.If you take a left a-arm, turn it upside down and place it on the right a-arm it lines up.The curve of the a-arms match.Now you have the reverse problem with the pivot points.So what i have done is make a spacer out of 2" tubing.I used a old ball joint for my pattern and made a hole in the tubing for the top of the ball joint to fit in.Now i have the two pivot almost in line.The next thing i will do is notch out the a-arm.Are rules allow us to reinforce the a-arm along the edges which are now on top.Can this work and what other problems do i need to look at?
Thank You

istock59
Dirt Forum Champ
Total posts: 508
posted November 29, 2005 07:18 PM  
Maybe I'm missing something here, but unless you change the location of the pivot points by moving the frame mount holes or increasing the spindle height (diff spindles or taller ball joints), then what exactly would turning an OEM a-arm over do? If the distance between the pivot points is the same and the points are in the same location, it doesn't matter what shape the a-arm is.

Or look at it this way. If you draw a straight line from the cross-shaft to the center of the balljoint, this line is the same regardless of whether the a-arm is rightside up or upside-down (and swapped side-to-side).

[This message has been edited by istock59 (edited November 29, 2005).]

Koolaid
Dirt Maniac

Total posts: 104
posted November 30, 2005 02:28 PM  
Timmer - I would have to agree with istock59 - if you required to run an OEM (stock height) spindle you aren't gaining anything. Now if you ran a tall spindle I could see where your plan would be an advantage, but it seems like a ton of work - especially when a-arms are consumables when you whack the wall with a metric car.

Timmer
Dirt Roller

Total posts: 7
posted November 30, 2005 05:49 PM  
Koolaid & istock59 the pivot points on a metric a-arm are not in line.the ball joint is below the mount.This is why you go to a taller spindle.To bring the ball joint in line with the mount.Then this creates another problem by causing the tire to lean way out at the top.So you have to go to a shorter a-arm,cutting it or going to a different a-arm.The rules wont allow this.So by turning the a-arm upside down, the ball joint mount is now on top.This allows you space the ball joint down towards the spindle and brings the pivot points more in line.Plus there is the possiblty to shim between the balljoint and spacer to help in getting caster ackerman etc,etc.Then you will have to cut the a-arm for frame clearance and then reinforce the a-arm.We are allowed to reinforce the a-arms.Look at a tublar a-arm,the ball joint and a-arm mount are in line.This is what im trying to achieve.

istock59
Dirt Forum Champ
Total posts: 508
posted November 30, 2005 06:58 PM  
Timmer, you never said anything before about taller spindle in your previous posts. I still don't think you'll gain much by flipping the arms, even with the taller spindle. But give it a try, maybe you're on to something!

ryan
Dirt Forum Champ
Total posts: 784
posted November 30, 2005 09:40 PM  
If nothing else you'll have a bunch of people looking at your car and saying

What the F**K did you do?

enduro80
Dirt Roller

Total posts: 14
posted December 01, 2005 04:16 AM  
I dunno but maybe i'm missing the whole point here.If you want to change your pivot points why dont't you just cut the upper left mount off of the frame ,lower it to the frame and get a taller upper balljoint?This would level the pivot point and you could also change your Camber curve to what you want.Sounds a lot easier then flipping control arms and notching them out.Maybe I just don't get the point here.

marrs
Dirt Full Roller

Total posts: 30
posted December 01, 2005 08:13 AM  
Really seems like a whole lot of wasted time and engineering, those stock arms are so weak they fold even on a little tire to tire contact, we lost like 8 arms this last season and it wasnt always the wall's fault.

Kool Performance Center
Dirt Roller

Total posts: 10
posted December 01, 2005 07:54 PM  
Not srue I can explain it real well but I will try.
On metric frame put right front upper on the left side.
Use a Nova Left lower on the right side.
Use a stock right Upper on the right side.
Use camaro spindles, they are taller.
There is an adapter bracket so you can still use the small brakes.

I just tell everyone use 2 right side uppers and 2 left side uppers. The response is usually, A puzzled look.

This set up gives you upper a arm angle and also moves the right front out and forward.

Call me and I will try to explain it better.
Also can and I can give you info on tie rods, idler arms, etc

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Kool Performance Center
Dirt Roller

Total posts: 10
posted December 01, 2005 07:56 PM  
Sorry the number is 812-464-5665

Timmer
Dirt Roller

Total posts: 7
posted December 01, 2005 08:17 PM  
Heres the problem are rules wont allow us to touch the a-arm mount or the a-arm.It has to be oem and these a-arms are junk.So my theory is if you look at a tublar a-arm the mounts are on the same line(ball---mount)You also use the oem spindle.Metric a-arm the ball is below the mount(ball/mount).The angle of the line after the weight of the car is placed on these two points determines your roll center.The straight line should angle up toward the ball.With the metric this wont happen.One way to fix this is with taller spindle.But with the oem a-arm it causes the tire to lean way out at the top.So take the left a-arm turn upside and the ball mount is now above the a-arm mount(the left is used on the right side).So you make a spacer to bring the ball down to the line that the a-arm mount is on.So when you put the weight of the car on these two points the line will angle up like a tublar a-arm.This is what im trying to figure out.

3dracer
Dirt Full Roller

Total posts: 34
posted December 02, 2005 02:13 PM  
I see what he is trying to say. It seems to make since to me if you must yuse stock stuff.

hotrodenford
Dirt Full Roller

Total posts: 69
posted December 02, 2005 04:46 PM  
I understand what you are trying to do. but unfortunatly it wont change the "geometry". See the pic below. You state that you upper balljoint is lower than the a-arm mount. thats not good! are your lower arms level? if not you have your ride heights set way too high. A stock metric street car has about as much angle as shown in the pic. If your car is as low as you can get it you are not going to change anything by fliping a-arms side to side or up and down. The ONLY way to change your camber curve is to change the relativeivity between points "A" and "B".
this can be acomplished buy any or all of the folowing: 1. Move point "B" down buy changing the mounts on the frame. 2. Move point "A" up buy geting a taller spindel (dimension "C") or get a dimensonaly taller ball joint(minimal difference). 3. Change the distance between point "A" and "B" buy geting a different a-arm. A shorter arm will net more change in camber angle per travel.

Basicaly you need to get the tallest spindel you can find(impalla?), and the shortest upper arm or longest lower arm. If you use stock car parts how is anyone going to know you have a nova instead of a metric?

You have to phisicaly move the pivot points in relation to each other. If you use the same balljoint attached to the same spindel with the same tire in the same relation to the car, it dosent matter what shape (upsidedown?) the a-arm is, nothing changes.

I hope this clairfies it just a little!

Whatever you do don't let this burst your bubble! Keep thinking about it and you might come up with the latest GREAT idea!
http://www.amwildracing.com/upperarm.jpg

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If it has wheels or a skirt, you can't afford it! But they shure are fun...

Timmer
Dirt Roller

Total posts: 7
posted December 03, 2005 05:20 PM  
hotrodenford thank you for the info.Your picture will help.What im still trying to do is improve the roll center.If you take the arm in your picture and lay it flat on a bench.The pivot points on "A" and "B" are in the same line.This is were you want to start out at.Now take the metric upper a-arm(you will need to clamp the arm at the ball joint mount to the bench)the two pivot points are not in the same line.In your pic.pivot "A"is below "B".This is how the a-arms are made(junk).To fix this we go to a taller spindle"C" but this cause the wheel to lean out ot the top.So you have to go to a different a-arm or start cutting.Rules wont allow this.So my theory is to take the left a-arm,turn upside down and place on the right side(the curves of the a-arm match).Now in your picture i have taken pivot "A" and placed it above pivot"B"(take the upside a-arm and clamp it to the bench at the mount side).To bring pivot "A" in line with "B" i use a spacer(2"square tubing,old ball joint as pattern).Now i have the two almost in line which is were you want to start at(according to what i have read).Yes i will have to notch out the a-arm but we are allowed to reinforce the a-arm along the edges for strength.These edges are now on top.So this is what im trying to figure out and what else i have to do.Maybe some day we will get to use tublars. Thank You

gahainsey
Dirt Maniac

Total posts: 116
posted December 03, 2005 05:56 PM  
Your balljoint pivot is still in the same spot relative to the spindle. The geometry will not change. The 'effective' control arm is still a line from the balljoint pivot to the inner A Arm pivot. The shape of the contol ar connecting these two points is irrelevant.

Koolaid
Dirt Maniac

Total posts: 104
posted December 03, 2005 07:36 PM  
Are you using stock metric spindles or tall spindles?

dirtrace54
Dirt Freak

Total posts: 215
posted December 03, 2005 11:34 PM  
i think i see what hes saying. the ball joint is at an angle in the arm compared to the inner mounting points. so when its upright and you clamp the arm to a bench the moutning points are in the air. with an angle ball joint mounting plate on the a-arm, when you flip it it does actually move the ball in relative to the inner mounting points. if the plate was straight like a tubular or a camaro upper, it wouldnt make a difference.

seems like alot of work for very very little gain. JMO

Timmer
Dirt Roller

Total posts: 7
posted December 05, 2005 05:31 PM  
This project is looking like it will be more work and very little gain.The best thing i can do is hope for tublars.But man these oem upper a-arms are junk.Thanks to all for the info.Keep thinking outside of the box and if you are in IND. stop by KMS Speedway.
Thank You
Timmer

john56h
Dirt Roller

Total posts: 16
posted December 05, 2005 07:04 PM  
This practice of inverting the a-arms and switching side for side used to be very common at the since closed Flemington Speedway (New Jersey). This was a fast 5/8 mile asphalt track and the guys were swapping in the Impala (early 70's) spindles so they could mount Grand National hubs at least on the RF. Impala spindle is so tall they'd have to do what you are describing. They probably figured out how to improve roll centers in the process (but remember this was asphalt). A guy by the name of Rusty Turbush was the master of Flemington's Streeters. If he's still around, he'd be the one to ask. Also, Pride Conner and Clyde Cox.

Timmer
Dirt Roller

Total posts: 7
posted December 06, 2005 06:08 PM  
john56h
Thanks for the info.The track i'll be running on is a 3/8 mile high banked.Gets slick for the features.Trying to find anything that give me a little advantage.
Thank You

  

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