I have a question for the suspension experts of the board

[Big Bald]

When i go over bumps the car jerks to the side. HOW DO I STOP THIS? It feels like i am losing control of the car or like it is slipping on some ice. My mods are 2" Dropzone springs, KYB GR2s, Front and Rear Upper strut Towers braces....tell me what i am missing or need to replace. Thanks.......

 

[nowayout]

Have you check everything over to make sure nothing is loose.

There not much you can do in adjustment wise. As long as it installed correctly.

 

[Big Bald]

Yes everything is tightened. I am not sure what could be causing this.

 

[Turbo Guru]

Have your alignment checked and also check to see if any of the main suspension bushings have failed /worn out.

Joe

 

[2-0turbo]

If your camber is way off, it can do some funny things. What kind of bump? When both front wheels hit it at the same time, like a bridge expansion strip? Or when just one wheel hits something like a pothole. If you hit a bump with your passenger side, front wheel, does it "jerk" to the passenger side?

 

[TaLoNBLiNGBLiNG]

It's called "Bumpsteer"

Check for any looseness in the suspension parts (tie-rods, control-arm bushings, ball-joints).

 

[Big Bald]

Originally posted by 2-0turbo
If your camber is way off, it can do some funny things. What kind of bump? When both front wheels hit it at the same time, like a bridge expansion strip? Or when just one wheel hits something like a pothole. If you hit a bump with your passenger side, front wheel, does it "jerk" to the passenger side?

That is exactly what is does. It jerks mainly on the passenger side. Once in a while on the driver side. Bumps = potholes, highway bridges, etc. Would this energy suspension kit help this? Don't know much about it but it was recommended.

 

[2-0turbo]

Originally posted by TaLoNBLiNGBLiNG
It's called "Bumpsteer"

Check for any looseness in the suspension parts (tie-rods, control-arm bushings, ball-joints).

I know what bumpsteer is--not a big concern on a rack and pinion setup. Our suspensions are not terribly prone to it (1G's anyway). I know less about the 2G suspensions, but know they use a upper/lower control arm on the front. They do not control the camber with the front strut like our 1G's do. He states he has a 2" drop. That will cause excessive negative camber unless he has corrected it.

He didn't really answer my question (I'll rephrase it), but if he is running a lot of negative camber, that creates a side load. I was hypothesizing that, he was running so much, when he hit a bump, the load on the other wheel would tend to push the front of the car around--this would feel like a "jerk".

I totally agree with you though, he needs to make sure everything is tight and nothing loose. This is certainly easy to check and could solve the problem very quickly.

BTW, your car is looking pretty nice in that shot! I really like the whole setup you have going on.

 

[2-0turbo]

Originally posted by Big Bald


That is exactly what is does. It jerks mainly on the passenger side. Once in a while on the driver side. Bumps = potholes, highway bridges, etc. Would this energy suspension kit help this? Don't know much about it but it was recommended.

I was kind of looking for one or the other--not both. It really sounds like you have something loose. Have you checked your rack to make sure it is secured? What about your tie-rod ends? Lower ball joints? As others have stated, it could be your alignment. What settings are your running? Are the tops of your front tires visibly leaned in towards your engine?

 

[TaLoNBLiNGBLiNG]

Acutally, now that I think about it... Check your inner tie-rod ends, housed withing the bellows boots on your Rack and Pinion. If one of the boots is cracked or ripped, the steering will be affected, that's for sure. I get madd bump steer because the inner tie-rod end on the driver's side of my car is ripped and there is a lot of play in the steering. While you're under there checking the suspension components, you might as well check the steering linkages too.

BTW 2-0turbo: Thanks for the compliment

 

[Big Bald]

Thanks for all the replies i will recheck and check alot of what was suggested and go from there.

 

[New_Talon1998]

hey bro get an alignment it sounds like your toe is off and that will cause the front or rear which ever you are having a problem with to jerk out of control when you hit a bump

Debbie

 

[Velo7825]

Well I'm in the same boat, when I hit bumps my car will tend to steer toward the side of the road the bump was on. I've searched for bumpsteer on this forum and only came up with this thread. Here's my Theory and a possible fix. Also I'm absolutly sure my alignment is correct, and I have a 1.75 inch drop in front. here is an article about it.
http://www.modularpower.com/bumpsteer.html

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First As you see here when the ride hieght is at atock levels the tie rod arm is level with the steering rack, also note that on a 2g the tie rod ball joint is located on top of the knuckle mounting point.

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As we lower the car the steering rack lowers and the tie rod goes up at an angle to where it connects on the knuckle.

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If you look at the arc of the arm as a circle you can see that when the arm is at zero degrees the movement is mostly up and down. you only get slight variences in the horizontal direction. but as the arm is angled the movement starts to get more and more horizontal.

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Another adverse effect is that the stroke of the steering is reduced because you are at an angle, and we all know that these cars have an awfull turning radius to begin with, especially the awd's

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So could we just take the ball joint and flip it over so it mounts on the underside of the knuckle mounting point. this would lower the end of the arm about 1.5 inches. The only problem i could think of is that the whole for the ball joint might be tappered so it wouldn't seat properly.

Does anyone know anything about this? do they already make a kit like in the above link for our applications? Can anyone come up with a fix for the tappered whole if that does indeed cause a problem?

 

[jtmcinder]

I know what bumpsteer is--not a big concern on a rack and pinion setup.

GMFB!

Bumpsteer is a huge issue on 2Gs.

- Jtoby

 

[Denji]

my friends lowered eclipse 2g does the same thing.. he let me drive it and sure enough sounds like the same thing..we are working on figuring that out tomorrow, i will update if we find anything out.

 

[jtmcinder]

Does anyone know anything about this? do they already make a kit like in the above link for our applications? Can anyone come up with a fix for the tappered whole if that does indeed cause a problem?

There are tons of kits that do exactly as you drew for cars like F-bodies and Mustangs. I've never seen one for a DSM. Unfortunately, you are correct about a taper to the ball-joint mount on the knuckle, so a simple flip is out.

Toeing out under compression is a serious problem and it gets much worse when a 2G, for example, is lowered, putting the car in a steeper section of the front bump-toe curve. It causes the nose to become darty under hard braking, which can only be dealt with (in the absence of a bump-steer kit) by dialing in some static toe-in. But static toe-in kills turn-in and makes the car hard to transition at near-constant speed (read: slalom).

The "standard" solution under these conditions is to raise the rack. But that's not a day-with-basic-tools sort of job. And it's not legal in most classes.

All of this makes me more jealous of WRX drivers. Their rack is in front of the axle, which gives all sorts of benefits, most notably that they gain toe-out when they slap over their camber plates in the paddock. If you want to adjust camber and toe on a 2G after driving the car to the event, you need a portable alignment set-up or a good memory for how many turns such-and-such needs.

- Jtoby <- runs front toe-out all the time and doesn't let others drive his car on the street

 

[2-0turbo]

GMFB!

Bumpsteer is a huge issue on 2Gs.

- Jtoby

My original post was "I know what bumpsteer is--not a big concern on a rack and pinion setup. Our suspensions are not terribly prone to it (1G's anyway). I know less about the 2G suspensions, but know they use a upper/lower control arm on the front.

What I meant by that is that rack/pinion setups are less prone to bumpsteer problems, then say something with a steering gear with Pittman arms, or a Ford twin-traction beam setup. Velo with the graphics illustrated best. I'm not saying it doesn't happen, but the bump/toe changes with a rack setup are much reduced over previous steering geometry designs.