Instant center AS and IC ht. numbers
10-06-2009, 04:43 PM
#1
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Instant center AS and IC ht. numbers Current set up after changing ride ht
IC Length 56.25
Ht 5.188
AS 46.572
I can make an adjustment to put it at
IC 45"
Ht 9.25
AS 103.806
Problem is, did a gear swap..... lowered ride ht to get rid of wheelstrand. Previously "AS" was at 130% and it would go on the bumper if you hit the gas.....
Now When you hit the gas it spins about 30-40 ft out but stays moving steady, not blowing the tires off. Barely bring the tire off the ground...maybe half inch
Would my adjustment be more desirable numbers?
IC Length 56.25
Ht 5.188
AS 46.572
I can make an adjustment to put it at
IC 45"
Ht 9.25
AS 103.806
Problem is, did a gear swap..... lowered ride ht to get rid of wheelstrand. Previously "AS" was at 130% and it would go on the bumper if you hit the gas.....
Now When you hit the gas it spins about 30-40 ft out but stays moving steady, not blowing the tires off. Barely bring the tire off the ground...maybe half inch
Would my adjustment be more desirable numbers?
10-06-2009, 11:19 PM
#3
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is there any place i could read about how to measure instant center and what the right instant center is for a given application. and how to adjust the suspension to achieve the best IC?
10-06-2009, 11:46 PM
#4
test different IC vs. power level is the only way to tell what your car likes. heres a pic to describe a torque arm IC.
as you can see, axle CL to torque arm CL is the length. where the LCA horizontal line crosses the torque arm vertical line is your IC height.
as you can see, axle CL to torque arm CL is the length. where the LCA horizontal line crosses the torque arm vertical line is your IC height.
10-07-2009, 09:35 AM
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i think what promod is saying is your IC will remain the same length as long as you have the same length TA under the car... all you can adjust is the height of the IC.
10-07-2009, 09:51 AM
#7
Wouldn't the IC be calculated similar to a 4-link suspension where you draw a line through the center of the T/A and center of the LCA, and where those two points intersect is your IC? I always thought that in a torque arm car, the torque arm represents the upper controll arm like a 4-link. That drawing above doesn't seem to accurately represent that at all?
Mike
Mike
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10-07-2009, 09:53 AM
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im still not real sure... but these TA have a move-able link... they aren't mounted in a fixed position... i know that changes something... treating the TA as a upper link would make sense to me any ways...
Last edited by ty_ty13; 10-07-2009 at 09:58 AM.
10-07-2009, 10:16 AM
#9
Wouldn't the IC be calculated similar to a 4-link suspension where you draw a line through the center of the T/A and center of the LCA, and where those two points intersect is your IC? I always thought that in a torque arm car, the torque arm represents the upper controll arm like a 4-link. That drawing above doesn't seem to accurately represent that at all?
Mike
Mike
A torque arm wont swing up and down without the rear end moving like a 3/4 link bar would if you unbolt it from the chassis side since its fixed at 2 points on the housing.
think about when the rear end tries to drive up. The chassis mount is seing a vertical force, not a rear ward force. its the same exact principle on a ladder bar. It sees an upward force not a rear ward since its a triangle bolted on the rear end. Thats the only simularity on a torque arm car vs. a ladder bar though.
The LCA horizontal line where it crosses this vertical line is going to be your sorce of IC.
The front torque arm mount has a slider or a shackle to remove the bind since the t/a length needs to change with suspension travel.
4 link/3link and a torque arm suspension are two totaly different setups
10-07-2009, 10:19 AM
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That would be true if our cars had a 3-link suspension with just a single bar from the top of the housing to some point on the chassis. from a side view it looks exactly like a 4 link.
A torque arm wont swing up and down without the rear end moving like a 3/4 link bar would if you unbolt it from the chassis side since its fixed at 2 points on the housing.
think about when the rear end tries to drive up. The chassis mount is seing a vertical force, not a rear ward force. its the same exact principle on a ladder bar. It sees an upward force not a rear ward since its a triangle bolted on the rear end. Thats the only simularity on a torque arm car vs. a ladder bar though.
The LCA horizontal line where it crosses this vertical line is going to be your sorce of IC.
The front torque arm mount has a slider or a shackle to remove the bind since the t/a length needs to change with suspension travel.
4 link/3link and a torque arm suspension are two totaly different setups
A torque arm wont swing up and down without the rear end moving like a 3/4 link bar would if you unbolt it from the chassis side since its fixed at 2 points on the housing.
think about when the rear end tries to drive up. The chassis mount is seing a vertical force, not a rear ward force. its the same exact principle on a ladder bar. It sees an upward force not a rear ward since its a triangle bolted on the rear end. Thats the only simularity on a torque arm car vs. a ladder bar though.
The LCA horizontal line where it crosses this vertical line is going to be your sorce of IC.
The front torque arm mount has a slider or a shackle to remove the bind since the t/a length needs to change with suspension travel.
4 link/3link and a torque arm suspension are two totaly different setups
10-07-2009, 10:33 AM
#13
it would hit it harder but it might spin the tires X number of feet out. It may like it pointed up but I would measure it through IC height and not LCA angle. 1 degree difference may be a lot of height change. You can try different holes on your LCA brackets and if your able to change your rear ride height, you can raise or lower the car to put the IC in a different spot that the holes on the bracket wont allow.
I've got to get back to work. I'll be back on around midnight. hopefully this thread doesn't explode with questions. haha.
I've got to get back to work. I'll be back on around midnight. hopefully this thread doesn't explode with questions. haha.
10-07-2009, 10:36 AM
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right i use ride height for fine adjustments... but this just changed everything i thought... of course i cant be a full believer with out measuring how the car sits now and doing some testing.... should make for a very interresting spring...
10-07-2009, 10:42 AM
#15
I can't stress enough how important testing is. Asking for a suspension setup on the internet is a tough one to do since these stock suspension cars are so different. The internet chassis setup is usually going to leave you with a lot left on the table.
Its a lot easier on a tube chassis 4 link car to compare without having the car infront of you. But You still have to be careful. I've seen some pretty scary and dangerous stuff being suggested to people on the internet.
Its a lot easier on a tube chassis 4 link car to compare without having the car infront of you. But You still have to be careful. I've seen some pretty scary and dangerous stuff being suggested to people on the internet.
10-07-2009, 01:53 PM
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alot of misleading information here
Legth of instant center is not fixed with a T/A.
relo brackes make IC shorter, basic stuff...... I know all that
Legth of instant center is not fixed with a T/A.
relo brackes make IC shorter, basic stuff...... I know all that