bump steer and roll center correction (work inn progress) - Suspension and Brake Forum

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bump steer and roll center correction (work inn progress)
Wednesday, August 18, 2010 3:30 PM
I want to correct this



with this



and the semi fail result



the spacer is not tall enough, but you can see the tie rod end is perfect



Location: Montreal, Quebec

Re: bump steer and roll center correction (work inn progress)
Wednesday, August 18, 2010 4:01 PM
Interesting....


Boost > N/A

180hp in 1989 or 260hp in 2008, you decide. Quad < Ecotec

Re: bump steer and roll center correction (work inn progress)
Wednesday, August 18, 2010 5:00 PM
Indeed it is. So youre spacing the ball joint from the CA?



Re: bump steer and roll center correction (work inn progress)
Wednesday, August 18, 2010 6:10 PM
TheSundownFire (GME Chat) wrote:Indeed it is. So youre spacing the ball joint from the CA?


yes and I have bolted the tie rod end from under on the knuckle I will post more soon



Location: Montreal, Quebec
Re: bump steer and roll center correction (work inn progress)
Wednesday, August 18, 2010 6:21 PM
Where is the pivot between the tie rod end and the rack in relation to the subframe? Roughly the same distance from the centerline of the car?

.



Re: bump steer and roll center correction (work inn progress)
Thursday, August 19, 2010 9:03 AM
Spacing the balljoint like that might change the angle of the arm, but it hasn't changed the relative pivot points, so roll center hasn't changed. The spacer needs to go on the knuckle side of the balljoint, not the arm side...

The tie rod end is interesting. Do you have any clearance issues with wheel extension (jacking the car up)?




fortune cookie say: better a delay than a disaster
Re: bump steer and roll center correction (work inn progress)
Thursday, August 19, 2010 9:30 AM
TheSundownFire (GME Chat) wrote:Indeed it is. So youre spacing the ball joint from the CA?


Yes, in doing so he will be correcting the roll center of the suspension. Personally I think it would be more beneficial to make a set of new arms that would be stronger and lighter, and also correct the roll center. The only problem I see with your fix is, #1 it will only be good for one drop. There is play in that style of fixing, but if someone is running CO or springs the spacer will have to be different thicknesses.#2 the pivot angle as someone mentioned will need to be determined so that there is no binding of the knuckle to CA when compressed and so on.

On a side noteI thinking your machining is superb by the way


http://www.overkillengineeringmotorsports.com/
Re: bump steer and roll center correction (work inn progress)
Thursday, August 19, 2010 10:07 AM
James Cahill wrote:Where is the pivot between the tie rod end and the rack in relation to the subframe? Roughly the same distance from the centerline of the car?

.


maybe a bite lower with the stock rod end


OHV notec wrote:Spacing the balljoint like that might change the angle of the arm, but it hasn't changed the relative pivot points, so roll center hasn't changed. The spacer needs to go on the knuckle side of the balljoint, not the arm side...

The tie rod end is interesting. Do you have any clearance issues with wheel extension (jacking the car up)?


I know the pivot point dont change, but most of the kit that i see on the web are build like that
I have 19" wheels so I have a lot of clearance

OEM wrote:
TheSundownFire (GME Chat) wrote:Indeed it is. So youre spacing the ball joint from the CA?


The only problem I see with your fix is, #1 it will only be good for one drop. There is play in that style of fixing, but if someone is running CO or springs the spacer will have to be different thicknesses

On a side noteI thinking your machining is superb by the way


This is not a problem it's only for my car
And thank you



Location: Montreal, Quebec
Re: bump steer and roll center correction (work inn progress)
Sunday, August 22, 2010 10:53 AM
this is what i do to the knuckle





new bushing in and ready to be welded


job done





wheels on and the ground with the steering turned the left





just need a good alignment and test drive








Location: Montreal, Quebec
Re: bump steer and roll center correction (work inn progress)
Sunday, August 22, 2010 12:53 PM
Listening.


Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: bump steer and roll center correction (work inn progress)
Sunday, August 22, 2010 3:36 PM
Looks good, was contemplating on boring and sleeving the tie rod to flip it.

"Oil Leak ? What oil Leak ? Oh, Thats Just The Sweat From All The HorsePower!!"


Re: bump steer and roll center correction (work inn progress)
Monday, August 23, 2010 4:13 PM
Now, that's interesting.



Re: bump steer and roll center correction (work inn progress)
Monday, August 23, 2010 4:30 PM
Re: bump steer and roll center correction (work inn progress)
Monday, August 23, 2010 8:47 PM
ok so help me get what i am seeing here... this thread reached the limits of my suspension understanding, unfortunately.

you've lowered the car so much that the CA is no longer at the ideal location of parallel to the ground.. right? so to correct that you made a bushing that pushed it back to where the CA was a bit closer... better for handling. i get that part.

but i dont really get moving the tie rod part... same principal im assuming? that the car is so lowered that now the the tie rod is in the wrong position?



Oldsmobile all motor > Saab/Opel boosted
Re: bump steer and roll center correction (work inn progress)
Monday, August 23, 2010 8:58 PM
i need those knuckles for my ssbc brakes ! lol interesting post though.



Re: bump steer and roll center correction (work inn progress)
Tuesday, August 24, 2010 6:50 AM
OEM wrote:
http://www.sr20-forum.com/bolt-bars/30241-bumpsteer-kit.html


This was my first idea but I chose a fancy way

z yaaaa wrote:but i dont really get moving the tie rod part... same principal im assuming? that the car is so lowered that now the the tie rod is in the wrong position?


This video will explain way better then me






Location: Montreal, Quebec
Re: bump steer and roll center correction (work inn progress)
Tuesday, August 24, 2010 1:16 PM
is that the nbody knuckle? i wish it worked with jbody hubs



Re: bump steer and roll center correction (work inn progress)
Tuesday, August 24, 2010 2:57 PM
Interested to see what a bump-steer gauge has to say.

Is that the stock stud on the tie-rod?

Would it not be more beneficial to go with a heim-joint setup, with a longer stud and spacers so you can space the tie rod further from the spindle? (ex. the tie rod will bind if any lower, etc.)



Theres no doubt that what you have done will change the bump-steer 100%, but am just curious if you had taken other things into consideration.

Awesome work! Go get an alignment!!!





Re: bump steer and roll center correction (work inn progress)
Friday, August 27, 2010 8:26 PM
Im interested in the ball joint spacers, my CA bushings hate me when i ride so low and lay out.
Re: bump steer and roll center correction (work inn progress)
Tuesday, August 31, 2010 5:36 AM
I got the car aligned today and now the car is @!#$ dangerous lol
any small bump on the road make the car dance
back to the drawing board



Location: Montreal, Quebec
Re: bump steer and roll center correction (work inn progress)
Tuesday, August 31, 2010 6:59 AM
What are the specs on your alignment? What did they put your TOE to?


http://www.overkillengineeringmotorsports.com/

Re: bump steer and roll center correction (work inn progress)
Tuesday, August 31, 2010 9:26 AM
OEM wrote:What are the specs on your alignment? What did they put your TOE to?


near to zero degree

the guy sat in the car and the toe change to like .5 degree




Location: Montreal, Quebec
Re: bump steer and roll center correction (work inn progress)
Tuesday, August 31, 2010 10:27 AM
That vid helped me understand more










~2014 New Z under the knife, same heart different body~
______________________
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2012 numbers - 4SPD AUTOMATIC!!
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Re: bump steer and roll center correction (work inn progress)
Tuesday, August 31, 2010 2:12 PM
I make this nice bump steer gauge today
I will try to adjust the bump steer the right way this time





Location: Montreal, Quebec
Re: bump steer and roll center correction (work inn progress)
Tuesday, August 31, 2010 3:51 PM
Heyy you forgot the level thingie lol










~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
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