|
Re: Balljoint swap with front rack?
[Re: SLOW67]
#954130
03/20/11 06:16 PM
03/20/11 06:16 PM
|
Joined: Jan 2003
Posts: 6,138
Melbourne , Australia
LA360
master
|
master
Joined: Jan 2003
Posts: 6,138
Melbourne , Australia
|
Your ackerman angle will be incorrect if you swap ball joints over from one side to the other. Put simply, there should be a straight line between the steering arm, ball joint and the centre of the rear axle on both sides. If you are having trouble visualizing that, I suggest a search on Google, as there are many articles online available. On top of that you then have Bump steer to worry about, but that is more concerned with the tie rod length, position of the steering rack etc.
Alan Jones
|
|
|
Re: Balljoint swap with front rack?
[Re: SLOW67]
#954135
03/20/11 07:32 PM
03/20/11 07:32 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
So what happens?  Every body I've asked says it causes "problems" but is never specific about what it does 
Part of your issue will be the rack itself... you need
the inner tie rod end(end of the rack) to be AT the
same place as the lower control arm inner pivot point
(where the T bar is)... that way the tie rod will end
up being the same length as the lower control arm
BUT your K-member is in the way and you need to get
full travel on the spindle... you could change(build)
a new upper A-arm the same length as the lower BUT
look where that point would be... not good
|
|
|
Re: Balljoint swap with front rack?
[Re: SLOW67]
#954137
03/20/11 08:19 PM
03/20/11 08:19 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
So using this theory my custom steering arms should sit outward closer to the wheel and tire to maintain the relationship with the rear axle/balljoint centerline correct? How much of a deviation from this line would be acceptable? On the rack mounting, rule of thumb is 3in from the rack centerline to the steering arm centerline correct?
The end of the steering are(outer tie rod end) you
will have in line with the centerline of the lower
ball joint.... that 3" on the tie rod end will work
in a drag car(but it will still scuff on the turns)
but you would like it straight
|
|
|
Re: Balljoint swap with front rack?
[Re: SLOW67]
#954139
03/20/11 08:54 PM
03/20/11 08:54 PM
|
Joined: Sep 2009
Posts: 928
NC
SLOW67
OP
super stock
|
OP
super stock
Joined: Sep 2009
Posts: 928
NC
|
|
|
|
Re: Balljoint swap with front rack?
[Re: SLOW67]
#954140
03/20/11 09:04 PM
03/20/11 09:04 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
So this will owrk then? (see attachment) the cardboard is a mock up of the steering arm. The first pic is just general to show the setup the second is a view from the top of the spindle with both balljoint holes lined up...
I assume its in line with the ball joint.... you
can raise that point IF needed so its on the same
plane as the rack
|
|
|
Re: Balljoint swap with front rack?
[Re: MR_P_BODY]
#954142
03/20/11 09:19 PM
03/20/11 09:19 PM
|
Joined: Jan 2003
Posts: 9,996
Frostbitefalls MN (Rocky&Bullw...
gregsdart
master
|
master
Joined: Jan 2003
Posts: 9,996
Frostbitefalls MN (Rocky&Bullw...
|
The best thing you can do is take measurements of the locations of the inner an d outer tie rod ends from the stock setup. This will provide you with a very good base point for properly locating the position of the new ends. Also you need to look at the length of the steering arms that were used with the rack in its original configuration. I had to shorten mine considerably. They are now half as long as before. Ignore the bad ackerman in my deal, it works OK on the track only.
To learn all about setting this deal up properly, there is a chapter in the chassis manual (or was) that describes bump steer and how to corect it, along with other info.
Last edited by gregsdart; 03/20/11 09:22 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
|
|
|
Re: Balljoint swap with front rack?
[Re: SLOW67]
#954143
03/20/11 09:30 PM
03/20/11 09:30 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
When its all held up its inline with the balljoint...carboard is hard to work with lol. I just want my angles to be right because this is mostly a street car  Thanks for all the help guys  oh btw MR_P_BODY I've been following your front suspension build and its giving me all these bad ideas lol keep up the great work 
I got mine all squared away... I have about 1" of off set,
I can live with that... not perfect but Ok.
You MAIN issue will be using a upper control arm...
being that its shorter than the lower... as the spindle
drops down the upper edge will swing in quicker and
cause your toe to go out... NOT GOOD.... unless you
can some how get the rack and tie rod at the same
point as the lower ball joint(both height and length)
so they pivot on the same arc as the lower arm does...
what I'm trying to say is the rack needs to be at the
lower control arm inner pivot point and the outter
tie rod needs to be at the ball joint height and be
on that same center line.... pretty much impossible
with the wheel and tire in the way
|
|
|
Re: Balljoint swap with front rack?
[Re: SLOW67]
#954146
03/20/11 10:15 PM
03/20/11 10:15 PM
|
Joined: Mar 2006
Posts: 9,835
MI, usa
dvw
master
|
master
Joined: Mar 2006
Posts: 9,835
MI, usa
|
Quote:
So what happens? Every body I've asked says it causes "problems" but is never specific about what it does
There are 2 issues. First is Ackerman. The purpose of Ackerman is to allow the inner wheel to turn in a tighter radius than the outer wheel. Think about a tight turn. The turning radius of the inner wheel could be half of the outer. By swapping the ball joints/steering arms the inner tire will turn in a larger radius than the outer causing tire scrub. It will cause toe in when turning,not good. The second issue is bump steer. Simple to figure out. Looking from the front of the car 4 points need to form a parallelogram. The inner tie rod,outer tie rod,lower control arm pivot,lower ball joint. Move the steering arm in the correct location and all will be OK. If not it'll drive like crap.
Doug
|
|
|
|
|
