I am about to do the 'drop the top suspension arm by 1"' mod on my LJ - cross member is out & ready to go, but looking at the location of the existing holes, it looks as though by lowering them by 1", they would be very close to the edges of the cross member....
Does anyone who has done this modification have some photo's?
Were the XU-1's the only Toranas that had this from the factory? My LJ is an Oct '73.... just wondering if it was something that the factory started doing later in the production run, maybe mine already has the mod, which would be why it doesn't look possible?
Lowering top arm on LJ
Started by
_jklumpp_
, Sep 28 2006 01:40 PM
71 replies to this topic
#2
rodomo
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Posted 28 September 2006 - 05:25 PM
From old forum:
Posted: Sat Apr 03, 2004 10:31 am Post subject:
Electra Blue
The suspension on the XU1 differs in that the mounting for the upper control arm is lowered on the crossmember. I don�t have the actual measurement but you are probably correct in calling it an inch.
There are two sets of bolt holes which indicate that the lower one was drilled somewhere along the production line.
The 1970 service bulletin notes as important the the upper control arm is always reinstalled in the lower mounting position.
I would confidently assume that it was for handling purposes.
From what I have read this mod can be carried out on any LC/LJ Torana
but I would check on that before you pull out the old Black and Decker and start drilling a few holes.
This was disccussed sometime ago on this BB with some pretty good and informantive information. Perhaps someone with Search capabilities could locate it and post a link.
Posted: Sun Apr 04, 2004 5:41 pm Post subject:
mounting the upper wishbone 1� lower will also give it a higher roll
center thus giving the car less body roll in the front.
and this i would say is the reasoning behined the revised mounting
position
Hope this helps in some way
Posted: Sat Apr 03, 2004 10:31 am Post subject:
Electra Blue
The suspension on the XU1 differs in that the mounting for the upper control arm is lowered on the crossmember. I don�t have the actual measurement but you are probably correct in calling it an inch.
There are two sets of bolt holes which indicate that the lower one was drilled somewhere along the production line.
The 1970 service bulletin notes as important the the upper control arm is always reinstalled in the lower mounting position.
I would confidently assume that it was for handling purposes.
From what I have read this mod can be carried out on any LC/LJ Torana
but I would check on that before you pull out the old Black and Decker and start drilling a few holes.
This was disccussed sometime ago on this BB with some pretty good and informantive information. Perhaps someone with Search capabilities could locate it and post a link.
Posted: Sun Apr 04, 2004 5:41 pm Post subject:
mounting the upper wishbone 1� lower will also give it a higher roll
center thus giving the car less body roll in the front.
and this i would say is the reasoning behined the revised mounting
position
Hope this helps in some way
Edited by rodomo, 28 September 2006 - 05:26 PM.
#3
_wildsix_
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Posted 30 September 2006 - 09:23 AM
I to want to do this mod, but once looking at where the new hole would be became concerned at how close it would be to edge. Can someone please post some pics.
#4
_82911_
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Posted 30 September 2006 - 11:10 PM
Rodomo, got that round the wrong way 
if you drop the inside of the top arms on an LC/LC Torana you lower the roll centre, not raise it.
As a matter of interest if you lower arms are pointing upwards at the balljoint end(as most are when lowered) your front roll centre is around 6" under the ground!
A lowre roll centre is Ok but in this case I feel that it is starting to get too far away from the centre of gravity, leading to excessive body roll.
You lower the top arm to give you more camber gain in bump/roll.
Yes the hole is 1" lower than the standard hole.
Do you need to lower the arm to make it handle?
Well I used to think so, but now I think there is a better way.At east on a Race car there is, for a road car, I'd still lower the arm.
Cheers Greg..
if you drop the inside of the top arms on an LC/LC Torana you lower the roll centre, not raise it.
As a matter of interest if you lower arms are pointing upwards at the balljoint end(as most are when lowered) your front roll centre is around 6" under the ground!
A lowre roll centre is Ok but in this case I feel that it is starting to get too far away from the centre of gravity, leading to excessive body roll.
You lower the top arm to give you more camber gain in bump/roll.
Yes the hole is 1" lower than the standard hole.
Do you need to lower the arm to make it handle?
Well I used to think so, but now I think there is a better way.At east on a Race car there is, for a road car, I'd still lower the arm.
Cheers Greg..
#5
rodomo
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Posted 01 October 2006 - 08:17 AM
Yep, after reading that again you are correct.
Note: Is copied and pasted from old forum as stated at top of post.
Note: Is copied and pasted from old forum as stated at top of post.
#6
Bazza
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Posted 01 October 2006 - 10:21 AM
HiI am about to do the 'drop the top suspension arm by 1"' mod on my LJ - cross member is out & ready to go, but looking at the location of the existing holes, it looks as though by lowering them by 1", they would be very close to the edges of the cross member....
Don't forget that the 1" is measured from the centre of the existing hole to the centre of the new hole. Not 1" from the bottom of the existing hole to the top of the new hole. The GMH diagram of the mod in the Fiv Antoniou seems to leave plenty of "meat".
Let me know if you need to see the pic and I will post it.
Bazza
#8
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Posted 01 October 2006 - 07:33 PM
Hi
Hope this helps
Bazza
Hope this helps
Bazza
#10
_jklumpp_
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Posted 03 October 2006 - 01:42 PM
Do you need to lower the arm to make it handle?
Well I used to think so, but now I think there is a better way.At east on a Race car there is, for a road car, I'd still lower the arm.
Cheers Greg..
OK, Greg...now you have me confused, as it was you that had originally told me to do this mod
!!Thanks for the pic Bazza - if the pic is accurate, it looks like it should work.....I'll have to look at it properly and check.
#11
gtrboyy
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Posted 03 October 2006 - 11:18 PM
Do you drill it where the two little dents are under bolt holes or do you have to measure it?
I think someone had once mentioned that they were marked from the factory,is that correct?
I think someone had once mentioned that they were marked from the factory,is that correct?
#12
_82911_
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Posted 05 October 2006 - 10:48 PM
Jason,
what I mean is that lowering the top arm is not always the best solution... But this depends on the result you are looking for.
I said " I used to think this was the best way... now I'm not so sure" a lot of this depends on the tyre being used as well as the length and severity of the use(abuse) the tyre will recieve.
For your application (hillclimb and sprints) as well as road use, I stick by my original comments... Lower the top arm by 1"
Cheers Greg..
what I mean is that lowering the top arm is not always the best solution... But this depends on the result you are looking for.
I said " I used to think this was the best way... now I'm not so sure" a lot of this depends on the tyre being used as well as the length and severity of the use(abuse) the tyre will recieve.
For your application (hillclimb and sprints) as well as road use, I stick by my original comments... Lower the top arm by 1"
Cheers Greg..
#13
makka
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Posted 05 October 2006 - 10:51 PM
so what do you do on yours then Greg?
thats if you dont mind sharing your secrets.
thats if you dont mind sharing your secrets.
#14
_82911_
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Posted 06 October 2006 - 12:22 AM
For the moment i would rather not say exactly what has been changed. Not at least untill the theory proves to be correct.
But as anyone who knows me will tell you, that you are all free to come have a look over/under the car at any meeting the car is racing at. I have nothing to hide or secret weapons in there...
Let's just say at this stage i am treating the problems and not the symptoms. If you are familiar with Torana suspension geometry you can work it out, they only really have 1 big problem.
Cheers Greg..
But as anyone who knows me will tell you, that you are all free to come have a look over/under the car at any meeting the car is racing at. I have nothing to hide or secret weapons in there...
Let's just say at this stage i am treating the problems and not the symptoms. If you are familiar with Torana suspension geometry you can work it out, they only really have 1 big problem.
Cheers Greg..
#15
makka
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Posted 06 October 2006 - 12:37 AM
I wasnt suggesting that you were gonna hide secrets
I have been thinkin what you have done, and I think I have got an idea....
I have been thinkin what you have done, and I think I have got an idea....
#16
_82911_
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Posted 06 October 2006 - 07:07 AM
Any of you guys can always PM me if you want to discuss?
Gotta remember that this car is a COMPETITION car and you never know who is luking
Otherwise always willing to help out.
Cheers Greg..
Gotta remember that this car is a COMPETITION car and you never know who is luking
Otherwise always willing to help
out.Cheers Greg..
#17
_LoneOranger_
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Posted 06 October 2006 - 08:02 AM
Excuse my ignorance Greg,
Where are you located and which car is yours?
I never got around to the Grp Nc cars at the Muscle car masters.
John.
Where are you located and which car is yours?
I never got around to the Grp Nc cars at the Muscle car masters.
John.
#18
_82911_
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Posted 06 October 2006 - 10:54 AM
Hi John,
Southern Highlands.
This is mine..
Cheers Greg..
Southern Highlands.
This is mine..
Cheers Greg..
#19
_jklumpp_
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Posted 06 October 2006 - 01:33 PM
Cheers for clearing that up Greg.
....now just have to have another look at how this 1" drop will work....
....now just have to have another look at how this 1" drop will work....
#20
_LoneOranger_
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Posted 06 October 2006 - 10:37 PM
I Know this car.
And a top looking car it is too.
Next time I'll meet and greet.
Regards, John.
And a top looking car it is too.
Next time I'll meet and greet.
Regards, John.
#21
_wildsix_
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Posted 13 October 2006 - 02:50 PM
In doing this mod, do you actually lower the car awell
#22
_JBird_
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Posted 22 October 2006 - 03:28 PM
Anyone know what the longer bolt length is or where you can get them from?
#23
_jklumpp_
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Posted 23 October 2006 - 01:38 PM
bolts should just be High tensile, available from a bolt supplier/ engineering supplies shop.
Lenght - I think i got 75mm, but not 100% certain. I basically just measured, an allowed additional for more shims.
Lenght - I think i got 75mm, but not 100% certain. I basically just measured, an allowed additional for more shims.
#25
_73LJWhiteSL_
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Posted 20 November 2006 - 11:23 PM
Ahhh... Finally i understand.
I been pooring over the LC Workshop trying to get a better understand of the LC/J Front suspension and have not understood how this mod works. Now i see.
Understanding the mounting bolts for the upper control arm run across the car instead of front to back like the lower control arm helps lots.
Now when i get around to rebushing my front suspension i will do this mod as well.
Steve
I been pooring over the LC Workshop trying to get a better understand of the LC/J Front suspension and have not understood how this mod works. Now i see.
Understanding the mounting bolts for the upper control arm run across the car instead of front to back like the lower control arm helps lots.
Now when i get around to rebushing my front suspension i will do this mod as well.
Steve
Edited by 73LJWhiteSL, 20 November 2006 - 11:29 PM.
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