Bump Steer kit for FB?
05-24-10, 04:11 PM
#1
Scott Howard
Thread Starter
Bump Steer kit for FB?
Does anyone know of a bump steer adjustment kit for the 1st Gen? I know Mazdatrix has one for the second gen. Thanks for any help.
05-24-10, 04:49 PM
#2
the only correction for bump-steer that i know of is by using "bump steer correctors," turn in spacers, ackerman correctors, roll center correctors, etc. etc. etc. you can get them at respeed, gforceengineering.net, or ISC might still have some. I have the 1.5" ISC ones and that made an amazing improvement for the turn-in on my car.
05-24-10, 05:41 PM
#5
yes. between the strut and steering arm on the lower control arm. Does anyone know if respeed's actually add more Ackerman like the gforce ones do? or are they like the ISC ones and just correct bump-steer issues from lowering? Well the blocks do add a tiny but of ackerman, but the gforce ones supposedly add much more as well as adding in camber gain and inside tire wall clearance. I got my ISC ones for $50 I'm trying to figure out if the gforce ones are actually worth the $150
05-24-10, 05:53 PM
#6
yes. between the strut and steering arm on the lower control arm. Does anyone know if respeed's actually add more Ackerman like the gforce ones do? or are they like the ISC ones and just correct bump-steer issues from lowering? Well the blocks do add a tiny but of ackerman, but the gforce ones supposedly add much more as well as adding in camber gain and inside tire wall clearance. I got my ISC ones for $50 I'm trying to figure out if the gforce ones are actually worth the $150
need Billy to chime in.
05-24-10, 06:39 PM
#7
Scott Howard
Thread Starter
I currently have 1" turn in spacers on the lower strut. So maybe I just need to add more if I lower my car more. 7's only sells ackerman arms. I think that I probably need 1.5" turn in spacers then. Has anyone measured the bump steer or ackerman with there setups?
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05-25-10, 07:38 AM
#8
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The G Force spacers also correct a VERY important issue: front roll center height for cars that have been lowered.
If your roll centers are not correct, you will have all sorts of handling problems. I have been road racing mine for 15 years now, and I have had the G-Force parts for maybe 10 years now, and I was amazed at how much better the car behaved when the roll center heights were corrected front and rear.
After getting the roll center height corrected, then you can move your tie rod locations around to get the bump steer minimized. Sorry, I do not know of a bolt on kit for sale to fix bump steer.
If your roll centers are not correct, you will have all sorts of handling problems. I have been road racing mine for 15 years now, and I have had the G-Force parts for maybe 10 years now, and I was amazed at how much better the car behaved when the roll center heights were corrected front and rear.
After getting the roll center height corrected, then you can move your tie rod locations around to get the bump steer minimized. Sorry, I do not know of a bolt on kit for sale to fix bump steer.
05-25-10, 08:02 AM
#9
The blocks that go between the strut and the steering arm are often called bump steer blocks but that is not 100% accurate. They are used to correct the roll center. Bump steer associated with lowering the car *may* be fixed with the blocks but not all the time since they are not designed to do so.
To accurately fix any bump steer issues you need the ability to put spacers between the steering arm and the outer tie rod. Since the stock outer tie rods are tapered to fit this is not possible. There are two ways to handle this. First is to drill out the steering arm for a bolt and use a rod end rather than a tie rod. You put spacers between the arm and the rod end and adjust the amount of spacers to remove the bump steer. Second is to have a part made the has a taper on one end to match the steering arm and a male protrusion that fits the ID of the rod end. Either way you go you will need an adapter from the LH thread metric tie rod to a imperial size rod end.
First picture is the bolt method:
Second picture is of the tapered part direction:
Bump steer is measured with a device like this:
Used like this:
Given enough demand we could work up a group buy on this.
-billy
To accurately fix any bump steer issues you need the ability to put spacers between the steering arm and the outer tie rod. Since the stock outer tie rods are tapered to fit this is not possible. There are two ways to handle this. First is to drill out the steering arm for a bolt and use a rod end rather than a tie rod. You put spacers between the arm and the rod end and adjust the amount of spacers to remove the bump steer. Second is to have a part made the has a taper on one end to match the steering arm and a male protrusion that fits the ID of the rod end. Either way you go you will need an adapter from the LH thread metric tie rod to a imperial size rod end.
First picture is the bolt method:
Second picture is of the tapered part direction:
Bump steer is measured with a device like this:
Used like this:
Given enough demand we could work up a group buy on this.
-billy
05-25-10, 11:38 AM
#11
Scott Howard
Thread Starter
That is exactly what I was originally talking about. Everything I read on bump steer had indicated that it was a matter of being able to adjust the tie rod/steering arm up or down at the mounting point. The turn in spacers are mainly for changing the roll center after lowering the car.
They say that it is best to have a little toe out under compression (for stability at turn in), then have some ackerman effect to negate the toe out at mid corner. This is what I'm trying to achieve.
They say that it is best to have a little toe out under compression (for stability at turn in), then have some ackerman effect to negate the toe out at mid corner. This is what I'm trying to achieve.
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