bump spacers or bump stops?

[kully 560]

I have a early 1974 260z new front end new stock springs and tokico hp shocks. everything is new. alignment is perfect camber and caster. I have tt tunning lower adjustable control arms and tt tunning adjustable tension control rods . very happy so far except for the bump steer when I hit a bump the steering wheel jerks. no experience in bump steer or bump stop parts . so which one do I change or add ?thanks kully

[EuroDat]

If your using new stock (standard ride height) springs you shouldn't need bump steer spacers. They correct the geomentry with the car is lowered.

It could be in your alignment settings since the camber and caster settings are now adjustable. Do you now wat the settings are?

Here is a thread from Blue you can read about his settings compared with recommendations from John Coffey?

Chas

Edited August 21, 2013 by EuroDat

[kully 560]

front left camber is-0.3 degrees and right is -0.4 degrees , caster is front left 3.0 degrees and right is 3.1 degrees. toe is front left 0.16 degrees and right is 0.15 degrees SAI front left is 12.6degrees front right is 13.0 degrees , including angle is front left 12.4 degrees and front right is 12.6 degrees . tires @ 32 psi thanks kully

[EuroDat]

Here are some threads with settings. Your settings are pretty close to them.

http://www.classiczcars.com/forums/wheels-tires-brakes-s30/47764-alignment-shops-arghhhh.html

http://www.classiczcars.com/forums/suspension-steering-s30/49235-toe.html

I had some problems with bump steer which was caused by the solid PU bushes on the tension rods. I changed them to the TC kit and that reduced it to an aceptable level for me. Then again, Im not racing it or anything like that.

Chas

[jfa.series1]

Per EuroDat's comment, if you've gone to poly bushings on the control arms, T/C rods and steering rack, you have eliminated all compliance in the suspension and steering. Everything is going to get transmitted directly back to the steering wheel - great for racers and A/X'ers; not so good for the average street car.

[kully 560]

I have stock rubber bushings all around except for the ttt lower control arms and tension control arms, these all have the hiem joints which will help in feed back. but the bump steer I would like to cure if possible . do you think this could be fixed or just have to live with it ?

[jfa.series1]

I have stock rubber bushings all around except for the ttt lower control arms and tension control arms, these all have the hiem joints which will help in feed back. but the bump steer I would like to cure if possible . do you think this could be fixed or just have to live with it ?

With two of the three I listed as hiem joints - solid metal and even harder than poly bushings, your dealing with a compliance issue. There is nothing flexible to absorb road shocks so they have to be transmitted back to the wheel. Technically this is not a bump steer issue as you are running stock geometry and a perfect alignment. I think your choice of suspension parts has you well on down the path of "living with it".

[kully 560]

I think you are right. just as usual we never stop improving our z cars . it is not bad at all, just looking for a little better performance .did not know much about these bump steer spacers thought it might help. thanks for you help kully

[EuroDat]

I have never used them, but MSA sell them in two sizes, one thins set for 14" wheels and a thicker set for 15" and larger. Check their performance section under steering upgrades.

These things only help if you lowered the ride height. If the ride height is using "stock springs" they will make little difference.

Their purpose is to lower the end of the control arm close to horisontal and bring it back towards its original position.

Chas